Have you ever tried cooking fried rice using freshly cooked rice? How was the texture, though? If it turned out soggy, that’s because of its excess moisture. The next time you cook rice, try to let the rice age a little. Nothing beats leftover rice, especially one-day-old rice, when making fried rice. And here’s why.

Rice primarily consists of starch molecules. Starch is a complex carbohydrate composed of amylose and amylopectin polysaccharide. Amylose represents a linear and relatively unbranched glucose chain in starch, connected by alpha-1,4-glycosidic bonds. This contributes to a denser, firmer texture in starchy foods. In contrast, amylopectin forms a highly branched glucose chain with alpha-1,6-glycosidic bonds, resulting in a more porous and granular structure that imparts a sticky, creamy texture to starchy foods.

ONE-DAY-OLD RICE RESISTANT STARCH FRIES BETTER

When the rice is mixed with water and subjected to heat, the starch granules expand as water infiltrates its core. Gradually, the granule absorbs a sufficient amount of water and swells to an extent where it disintegrates into a matrix of starch molecules combined with water.

When the cooked rice is refrigerated, the starch molecules gradually undergo a reformation process called retrogradation. In food chemistry, retrogradation refers to the phenomenon in which starch returns or reverts to a crystalline structure as it cools down. The result of retrogradation is the formation of resistant starch. This is the same reason why bread in the refrigerator hardens over time.

Resistant starch is the type of starch that our body cannot break down. When used in frying, the retrograded crystalline starch can provide a unique texture, resulting in a crisper and a denser finish in certain fried foods.

In one study, the levels of resistant starch in different rice samples, including freshly cooked white rice, rice cooled for 10 hours at room temperature, and rice cooled for 24 hours at 4°C and then reheated. The results indicated that the freshly cooked white rice had the lowest resistant starch content at 0.64 g/100 g. The rice cooled at room temperature for 10 hours showed an increased resistant starch content of 1.30 g/100 g, while the rice cooled at 4°C for 24 hours and reheated had the highest resistant starch content at 1.65 g/100 g.

The results indicate the duration of cooling and reheating can influence the resistant starch content in rice. The longer the rice is in the refrigerator, the more resistant starch is formed. This is the reason why fried rice recipes usually call for leftover (one-day old) rice—its resistant starch makes it fry better than fresh rice.

FRESH COOKED RICE IS THE ONLY OPTION? TRY THESE

If you don’t have any leftover rice available, there are several steps you can take to prevent your fried rice from becoming soggy. The key idea here is to minimize the moisture content in the rice.

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To begin, spread the freshly cooked rice out on a tray or baking sheet. Allow it to cool and air dry for a while. Alternatively, you can speed up this process by briefly storing the rice in the refrigerator. However, it’s important to keep in mind that the longer the rice stays in the refrigerator, the more resistant starch it forms.

Another strategy involves managing the amount of liquid seasonings you add to your dish, such as soy sauce or oyster sauce. Especially when working with fresh rice, it’s wise to be cautious and potentially reduce the quantity of liquid seasonings to avoid introducing excess moisture.

Additionally, when cooking the rice, use a hot pan or wok and continuously stir. This technique not only ensures even cooking, but also promotes the evaporation of any excess moisture. The application of high heat in this process helps rapidly dry out the rice, contributing to the creation of a flavorful fried rice that isn’t soggy.

The post Why One-Day-Old Rice Should Be Used For Fried Rice appeared first on The Food Untold.

Did you ever wonder why bread that’s left over becomes hard and dry, or why rice gets grainy when it’s been in the fridge for a while? Well, it’s because of something interesting called starch retrogradation. This is a natural process that happens in foods with a lot of starch (like bread and rice), and it’s what causes the texture to change and the food to not taste as fresh as before. It’s like the reason why food becomes “stale.”

In this blog post, we will discuss starch retrogradation, exploring its science, effects on food, and how to minimize its impact on our culinary delights.

UNDERSTANDING RETROGRADATION

Starch is the most common carbohydrate in plants. It is made up of two kinds of molecules: amylose and amylopectin. Amylose is arranged in a straight chain, while amylopectin has a more complex, branched structure. I’ve written another article that talks about how these two differ. You can find it here. When we cook or work with starchy foods, the starch molecules soak up water and expand, which is why dishes can become thicker and turn into a gel-like texture.

On the flip side, retrogradation stands as the process wherein starch molecules within cooked foods undergo a reorganization, adopting a more structured and crystalline arrangement. This intricate occurrence takes place when gelatinized starch gradually cools and sheds moisture, compelling the starch chains to bond and reform crystals. Consequently, the once tender and vibrant texture of the food undergoes a shift, losing its initial allure.

High amylose starches are predisposed to undergo retrogradation. This phenomenon becomes evident in baked goods that lose their initial fresh taste and texture, signifying the transition from a gel-like starch state. Similarly, residual long-grain rice experiences this process due to its elevated amylose content, causing it to become rigid and less palatable.

Several factors impact the speed of retrogradation. These include the ratio of amylose to amylopectin molecules, which form the starch; the way these molecules are structured due to the plant source of the starch; temperature; how concentrated the starch is; and the existence and amount of other components, especially surfactants and salts.

THE SCIENCE BEHIND THE PROCESS

Starch retrogradation initiates promptly after the baking phase concludes and the product commences its cooling journey. This phenomenon is particularly pronounced in products containing a high concentration of amylose starch. Amylose, a linear starch molecule, undergoes retrogradation more swiftly than its counterpart, amylopectin. Notably, by the time the baked product reaches room temperature, the process of amylose retrogradation is often nearing completion.

However, the story doesn’t end there. The retrogradation of amylopectin, a branched starch molecule, requires a more extended period compared to amylose retrogradation. This temporal discrepancy between the two starch components imparts a significant impact on the overall quality of baked goods, contributing significantly to the phenomenon known as staling.

Staling, the undesirable transformation of baked goods from their fresh and soft state to a more rigid and less palatable one, is predominantly driven by the retrogradation of amylopectin. Over time, during the staling phase, the once pliable and amorphous amylopectin molecules revert to their original crystalline state, forming rigid granular structures. This process results in the expulsion of moisture from the product’s crumb, causing a loss of moisture content.

As a consequence of the expelled moisture, the texture of the baked product undergoes a noticeable change. The product gradually becomes firmer and less elastic, a stark departure from its desirable characteristics. This loss of moisture and alteration in texture are key attributes of staling, rendering the product less appealing to consumers.

COMMON FOODS THAT UNDERGOES STARCH DEGRADATION

Starch retrogradation is something that happens to many common foods we eat. Let’s take a look at some examples: bread, pasta, rice, potatoes, and crackers.

Think about bread. When it’s fresh out of the oven, it’s soft and chewy. But as it sits for a while, it becomes dry and crumbly. Even the outside part, the crust, turns tough and less yummy.

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Pasta is another example. When you cook pasta and it’s hot, it’s nice and soft with a little bit of chewiness. But as it cools down, it starts getting harder and not as tasty. That’s why leftover pasta isn’t as good – it loses its good texture.

Rice also goes through changes. Right after you cook rice, it’s fluffy and moist. But as it gets cold, it becomes dry and the grains might stick together, making it not so great to eat.

Potatoes, like the ones you might have as fries or mashed, also change. After they’re cooked and then cool, they can turn from creamy and soft to kind of gritty and dry. That’s not as yummy.

And let’s not forget crackers. When they’re fresh, they’re crunchy and easy to break. But if you leave them out, they get softer and chewier over time.

These foods show us how starch retrogradation works. It’s like they’re going through a texture change after they’re cooked and then cool down. So, if your sandwich bread isn’t as soft or your pasta isn’t as good the next day, you can blame starch retrogradation for that!

FIGHTING STALING IN THE FOOD INDUSTRY

Emulsifiers, enzymes, and hydrocolloids emerge as key players in this pursuit, each wielding distinct functions that contribute to the modification of the retrogradation process, ultimately enhancing product quality and extending shelf life.

By dispersing fat molecules within a starch matrix, emulsifiers hinder the reassociation of starch molecules into a crystalline structure. Consider mayonnaise, a classic example of an emulsion. When emulsifiers are introduced, the resulting product showcases reduced starch retrogradation, leading to a smoother, longer-lasting consistency that defies the clumping and firming often associated with retrograded starches.

Another example of emulsier is glycerol monostearate (GMS). GMS is produced by adding glycerol to fat or oil which results in a mixture of monoglyceride and diglyceride. Incorporating GMS at 0.25–0.5% allows amylose to form a helical complex that retards the retrogradation of the starch.

Enzymes catalyze specific reactions, transforming complex molecules with precision. In the context of starch retrogradation, enzymes like amylases can break down starch molecules into smaller fragments, impeding their propensity to form rigid crystalline networks upon cooling. This enzymatic intervention not only enhances the texture but also extends the freshness of products. For instance, the addition of amylase enzymes mitigates the retrogradation-induced staling, resulting in loaves that remain softer and more enjoyable over an extended period.

Glycosyltranferase is another enzyme that adds more branching points to create modified starch. This results in enhanced functional characteristics such as increased solubility, decreased viscosity, and minimized retrogradation.

Hydrocolloids, a diverse group of substances with exceptional water-absorbing capabilities, contribute significantly to the fight against starch retrogradation. They do this by preventing the formation of tight crystalline structures during retrogradation. Imagine a fruit pie filling; the incorporation of hydrocolloids maintains the desired consistency and texture, resisting the undesirable textural changes stemming from starch retrogradation.

PREVENTING STALING OF FOOD AT HOME

An effective approach involves appropriate storage methods. For instance, when it comes to baked goods such as bread, placing them in an airtight container or plastic bag within a cool, dry location can effectively delay moisture loss and limit exposure to air. Although some might suggest refrigerating baked items, this might not be the optimal choice, as it could accelerate retrogradation. In fact, staling of bread happens most rapidly at 32°F (0°C) to 39°F (4°C).

For extended preservation, freezing is very effective at slowing down starch retrogradation and staling. However, it’s important to recognize that certain changes in texture may occur during the thawing process. Thus, it is recommended to take these potential alterations into account when planning the use of frozen starchy items.

When reheating starchy leftovers, it’s wise to choose gentle methods that safeguard the original texture. Employ techniques that minimize exposure to high temperatures, such as microwaving with a small amount of water or utilizing mild oven reheating. By adopting these methods, the risk of overcooking and excessive moisture loss is mitigated, ensuring that the starchy foods maintain their desired texture and overall quality.

References:

A. Chakraverty (2014). Postharvest Technology and Food Process Engineering. CRC Press.

W.Zhou, Y. H. Hui (2014). Bakery Products Science and Technology(2nd Edition). John Wiley & Sons, Ltd.

M. Kuddus (2018). Enzymes in Food Technology. Springer.

V. Vaclavik, E. Christian (2014). Essentials of Food Science (4th edition). Springer.

P. Cheung, B. Mehta (2015). Handbook of Food Chemistry. Springer

The post Starch Retrogradation: Understanding the Science Behind Stale Food appeared first on The Food Untold.

Have you ever been curious about the nature of acrylamide and how it develops in the food we regularly consume? Acrylamide is a naturally occurring compound that emerges when specific foods undergo high-temperature cooking methods like frying, baking, or roasting. The concern surrounding acrylamide stems from its potential impact on our health, particularly its association with cancer risk.

The purpose of this blog is to unravel the chemistry behind acrylamide, its formation process, and the consequences it may have on human well-being. Furthermore, we will explore the latest scientific research on the potential health hazards linked to consuming acrylamide.

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By gaining insight into the chemistry and formation of acrylamide, we can better understand its impact on the human body. We will address common questions regarding the effects of acrylamide and explore strategies for reducing its presence in our diets.

WHAT IS ACRYLAMIDE?

Acrylamide forms through a chemical reaction known as the Maillard reaction. This reaction occurs when certain amino acids and sugars in food react at high temperatures, typically above 248°F (120°C).

Acrylamide forms during frying, broiling, baking, and roasting due to the high temperatures involved, which promote the Maillard reaction and acrylamide formation.

These cooking methods also create a dry heat environment that allows for water evaporation and concentration of sugars and amino acids, further facilitating acrylamide formation.

Boiling and steaming, with their lower temperatures and presence of liquid water, are less conducive to acrylamide formation due to the absence of dry heat and the dilution of sugars and amino acids. In facts, conducted studies did not detect acrylamide in unheated and boiled foods.

Acrylamide, when present in high concentrations, is acknowledged as a neurotoxin. Animal studies conducted with acrylamide concentrations thousands of times higher than those typically found in food did not show an increased risk of cancer, although the applicability of these findings to humans remains uncertain. Ongoing research is exploring the potential connection between acrylamide and certain types of cancer, suggesting a possible increased risk. Despite the inclination to minimize acrylamide intake, a preliminary study revealed its presence in 40% of the American diet.

Mitigating acrylamide consumption can present difficulties due to its formation during everyday cooking practices. Nevertheless, there are approaches that can aid in reducing its presence in our diets. These strategies encompass refraining from overcooking or charring foods, selecting cooking techniques that generate lower levels of acrylamide (such as steaming or boiling), and embracing a diverse diet that emphasizes fruits, vegetables, and whole grains.

THE CHEMISTRY BEHIND ACRYLAMIDE FORMATION

Acrylamide formation requires specific compounds to be present in the food during high-temperature cooking. The main compounds involved in the formation of acrylamide are sugars (particularly glucose and fructose) and the amino acid asparagine. Here’s a breakdown of the compounds required for acrylamide formation:

1. Sugars: Sugars are essential for the Maillard reaction, which is responsible for acrylamide formation. During high-temperature cooking, the sugars undergo a series of complex chemical reactions with other compounds, including amino acids, resulting in the browning, aroma, and flavor development in cooked foods.
2. Asparagine: Asparagine is an amino acid naturally present in many foods, particularly those rich in protein, such as potatoes, grains, and coffee beans. When combined with sugars during cooking, asparagine plays a crucial role in the formation of acrylamide. Under high heat conditions, the Maillard reaction occurs between asparagine and reducing sugars, leading to the production of acrylamide.

While sugars and asparagine are key components for acrylamide formation, it’s worth noting that not all foods that contain these compounds will necessarily produce significant amounts of acrylamide.

It’s important to note that the exact mechanisms and interactions involved in acrylamide formation are complex and not yet fully understood. Studies have shown that reducing sugars containing a free aldehyde group can react with asparagine at temperatures exceeding 212°F (100°C), resulting in the formation of an N-glycoside compound. This N-glycoside is subsequently cleaved at the C-N bond, leading to the production of an intermediate that ultimately yields acrylamide. A study conducted in 2003 proposed a pathway illustrating the transformation of N-glycoside into acrylamide. Moreover, it has been observed that substances such as 2-deoxyglucose, glyoxal, and glycerol can also combine with asparagine to synthesize acrylamide.

FOODS COMMONLY ASSOCIATED WITH ACRYLAMIDE

Acrylamide is found in a range of foods that undergo high-temperature cooking processes. Fried potato chips (16-30%), potato crisps (6-46%), coffee (13-39%), pastry and sweet biscuits (10-20%), bread and crisp bread (10-30%) are the main contributors to the dietary exposure of western populations to acrylamide. Other foods contribute less than 10%.

The proportion of each food item in the total intake of acrylamide varies depending on the composition of the food basket in different countries. For instance, in Sweden, coffee contributes 39% to the total exposure while in the Netherlands it is only 13%. In the United States, fried potato products account for 35% of exposure while coffee accounts for only 7%.

Here are the food items commonly associated with acrylamide formation:

Potatoes

When potatoes are cooked at high temperatures, such as frying or roasting, the naturally occurring sugars and the amino acid asparagine present in the potatoes undergo a chemical reaction known as the Maillard reaction. This reaction leads to the formation of acrylamide, resulting in the characteristic golden-brown color and crispy texture of potato products like French fries and potato chips.

Coffee

Acrylamide is naturally formed during the roasting of coffee beans. The high temperatures involved in the roasting process cause the Maillard reaction to occur, resulting in the formation of acrylamide. The amount of acrylamide in coffee is primarily determined by the duration and temperature of the roasting process. On average, coffee contains between 249 and 253 μg of acrylamide. A study indicated that coffee substitutes have the highest level of acrylamide at 818 μg/kg, followed by instant coffee at 358 μg/kg, and then roasted coffee at 179 μg/kg. I have discussed acrylamide in coffee in a separate post.

Baked Goods

Baked goods, such as cookies, crackers, bread, pastries, and cakes, contain ingredients like flour, sugar, and fats, which are prone to acrylamide formation when exposed to high heat during baking. The Maillard reaction between the sugars and amino acids in these ingredients leads to the production of acrylamide, contributing to the desirable texture and flavor of baked goods.

Snack Foods

Snack foods like pretzels, corn chips, and popcorn are often processed at high temperatures, making them susceptible to acrylamide formation. The combination of starches, sugars, and high-temperature cooking methods during snack food production can lead to the formation of acrylamide.

Potato chips, being the most popular among consumers, often exhibit elevated levels of acrylamide in comparison to other snacks. This disparity can be attributed primarily to the naturally higher concentrations of reducing sugars and asparagine amino acid present in potatoes.

In contrast, vegetable chips and tortilla chips generally contain lower amounts of acrylamide when compared to potato chips. This difference is primarily due to variations in their composition and cooking methods. A study revealed that the levels of acrylamide in potato chips ranged from 117 to 2762 parts per billion (ppb), whereas tortilla chips demonstrated acrylamide levels ranging from 130 to 196 ppb.

Breakfast Cereals

Certain breakfast cereals, especially those made from grains like oats or rice, can contain acrylamide. This is because these cereals often undergo processes such as toasting or extrusion at high temperatures, which can trigger the formation of acrylamide through the Maillard reaction.

HEALTH RISKS

The discovery of acrylamide as a neurotoxin and carcinogen in heated foods has raised concerns about its potential health effects. When ingested, acrylamide is metabolized in the body and can form reactive compounds that may bind to DNA and proteins. This can potentially lead to genetic mutations and cellular damage.

Research has indicated that the consumption of foods high in acrylamide is associated with a higher incidence of certain cancers in humans, including ovarian, endometrial, breast, and kidney cancers. This was confirmed in several studies presented. In a 2010 study conducted by Harvard School of Public Health (HSPH), it revealed a heightened risk of ovarian and endometrial cancer in non-smoking post-menopausal women who regularly consume food and beverages with elevated acrylamide levels.

However, our current knowledge about the comprehensive effects of acrylamide on human health is limited. The available evidence primarily stems from studies conducted on laboratory animals rather than direct investigations into human exposure to acrylamide from food sources. Various organizations, including the US Food and Drug Administration (FDA), European Food Safety Authority (EFSA), and the American Cancer Society acknowledge the necessity for further research to fully comprehend the complete impact of acrylamide on human health.

To date, evaluations of epidemiological studies conducted on diverse populations suggest that there is minimal evidence linking dietary acrylamide to the risk of developing most common types of cancer. However, ongoing research endeavors will provide further insights into the potential correlation between acrylamide levels in foods and an increased risk of cancer.

REDUCING ACRYLAMIDE IN YOUR DIET

Although it is challenging to completely eliminate acrylamide from the diet, there are several measures you can take to reduce its intake. Within the United States, the FDA governs the permissible levels of residual acrylamide in materials that come into contact with food. However, there are presently no specific regulations concerning the presence of acrylamide in food products themselves. In 2016, the FDA released guidelines aimed at assisting the food industry in minimizing acrylamide content in select foods. It’s important to note that these guidelines serve as recommendations rather than enforceable regulations.

At home, you can follow simple steps that can effectively lower your consumption of acrylamide:

Avoid Overcooking or Burning Foods

Acrylamide formation is more likely to occur when foods are overcooked or burned. The darker the food is, the more arcylamide has formed. To minimize acrylamide levels, be mindful of cooking times and temperatures. Cook food only until it turned golden yellow or light brown. (See above illustration as provided by the FDA). Avoid excessive browning or charring foods, as this can increase acrylamide formation. Or better yet, opt for cooking methods that retain moisture, such as steaming or boiling, which tend to produce lower levels of acrylamide.

Opt for Cooking Methods with Lower Acrylamide Production

Certain cooking methods are known to generate less acrylamide compared to others. Steaming, boiling, and microwaving are gentler techniques that can help reduce acrylamide formation. When applicable, choose these methods over frying, baking, or roasting at high temperatures.

For instance, when preparing potatoes, steaming or boiling them instead of frying or baking at high temperatures can significantly reduce acrylamide formation. By opting for gentler cooking methods like steaming or boiling, you can mitigate the risk of excessive acrylamide production while still enjoying delicious and nutritious dishes.

Embrace a Varied Diet

You can reduce your acrylamide exposure by include a variety of foods in your diet. Make sure to include plenty of fruits, veggies, and whole grains in your diet. These foods contain lower levels of acrylamide and have several nutritional benefits..

Instead of relying primarily on processed snacks like potato chips or French fries, include a variety of fruits, vegetables, and complete grains in your meals.

Storage and Preparation

Proper storage and preparation methods can also play a role in reducing acrylamide. Store potatoes and other starch-rich foods in a cool, dark place instead of the refrigerator. The asparagine content of potatoes and similar foods is not significantly affected by storage conditions. However, it is known that long-term storage of potatoes below about 39°F (4°C) increases the level of reducing sugars, which potentially increases acrylamide formation during cooking.

Additionally, soaking raw potato slices in water for 15-30 minutes before frying can help remove some of the starch and lower acrylamide levels. Starch is a precursor to acrylamide formation during cooking. By soaking the potatoes in water for 15-30 minutes prior to frying, some of the starch on the surface of the potato slices can be leached out.

The water acts as a medium for drawing out the excess starch, which may contribute to a reduction in acrylamide formation during the cooking process. It is important to note that this technique may not completely eliminate acrylamide, but it can be a helpful step in minimizing its levels. I have discussed this in a separate post further: Why Soaking Potatoes In Water Is Important.

References:

J. Provost, K. Colabroy, B. Kelly, M. Wallert (2016). The Science of Cooking: Understanding the Biology and Chemistry Behind Food and Cooking. John Wiley & Sons, Inc.

N. A. Michael Eskin, F. Shahidi (2013). Biochemistry of Foods (3rd edition). Academic Press.

P. Cheung, B. Mehta (2015). Handbook of Food Chemistry. Springer.

A. Zeb (2019). Food Frying: Chemistry, Biochemistry, and Safety.John Wiley & Sons Ltd.

S. Damodaran, K. Parkin (2017). Fennema’s Food Chemistry (5th edition). CRC Press.

H. Belitz, W. Grosch, P. Schieberle (2009). Food Chemistry (4th Edition). Springer.

J. Velisek (2014). The Chemistry of Food. John Wiley & Sons Ltd.

The post Acrylamide In Food: Chemistry, Formation, And Health Effects appeared first on The Food Untold.

Starch, an essential part of our food, provides us and many other species with essential energy. It is a type of complex carbohydrate that is widely distributed in plants and serves as the main source of energy storage. Amylose and amylopectin are the two principal polysaccharides that make up starch. Although there are certain similarities between these two, they also have unique qualities that set them apart. This makes them fascinating objects of study.

Starch is classified as a polysaccharide, which is a type of carbohydrate consisting of multiple sugar molecules linked together. In the case of starch, these sugar molecules are primarily glucose units. The individual glucose units in starch are connected by glycosidic bonds, which are chemical bonds formed between the carbon atoms of adjacent glucose molecules. These bonds create long chains known as polysaccharides, mainly amylose and amylopectin.

Starch demonstrates distinctive chemical characteristics like retrogradation and gelatinization. Starch granules get gelatinized when heated in the presence of water, which causes the granules to expand and absorb water. The structured structure of starch gets disrupted during this process, which causes a viscous gel to form. However, retrogradation is the process whereby the gelatinized starch goes through a rearrangement upon chilling, resulting in the creation of insoluble amylose and amylopectin complexes. Retrogradation is the process that causes items made from starch to stiff or stale over time.

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Gelatinization and retrogradation are both processes that can be controlled by understanding the molecular structures and properties of starch, as well as its major components, amylose and amylopectin. The way they interact during cooking, baking, and using other food processing methods has a big impact on the qualities of the finished product, from sensory attributes to stability.

Let’s see the difference between amylose and amylopectin.

AMYLOSE VS AMYLOPECTIN

As already mentioned, amylopectin and amylose are two major components of starch. Amylopectin, a branching polysaccharide, accounts for the majority of starch. It has a linear chain of glucose molecules connected by α-1,4-glycosidic linkages, comparable to amylose. However, amylopectin contains more α-1,6-glycosidic linkages, which provide branching points. These branches appear at regular intervals, resulting in a heavily branching structure that looks like a tree. Amylopectin’s branch points enhance its molecular weight, making it bigger and more complex than amylose. The molecular weight of amylopectin is 300 times more than that of amylose.

Amylose is a polysaccharide composed of glucose units that are interconnected solely by α-1,4-glycosidic linkages, forming a linear structure. In contrast to amylopectin, amylose’s linear arrangement enables close packing and organization, leading to a more condensed molecule. The spatial orientation of glucose units within amylose tends to adopt a helical configuration, adding to its distinctive molecular shape.

The ratio of amylopectin to amylose in starch varies between sources and has a significant impact on its characteristics. Starches with a greater amylopectin content have more branching and, as a result, are more soluble and digestible. The branching form of amylopectin gives a wider surface area, allowing enzymes to easily reach the glucose molecules for digestion. Starches with a higher amylose content, on the other hand, have a more rigid and resistant structure, resulting in longer digestion and a more progressive release of glucose.

The ratio of amylose to amylopectin determines the characteristics and functions of native starches from diverse sources. Waxy maize has a nearly 100% amylopectin ratio; potato, tapioca, and rice starches also have a high amylopectin percentage when compared to wheat and dent corn starches. The trace amounts of phosphate, protein, and lipids also influence the properties of starch.

Let’s discuss further.

Solubility and Digestibility

The solubility of amylose is typically higher than that of amylopectin due to their contrasting molecular properties. Amylose has a more compact and orderly structure with fewer branches, enabling improved interaction between water molecules and the individual amylose chains. As a result, amylose exhibits greater solubility. The linear configuration of amylose facilitates the easy entry and hydration of water molecules, leading to the formation of a colloidal dispersion.

In contrast, amylopectin’s highly branched structure limits the interaction between water molecules and the starch chains. The numerous branching points and side chains in amylopectin hinder the water’s ability to effectively solvate and separate the individual chains. As a result, amylopectin exhibits lower solubility in water compared to amylose.

And in terms of digestibility, amylopectin is more digestible than amylose. The ratio of amylose and amylopectin is one factor that affects starch digestibility. Amylose’s linear structure makes it more resistant to enzymatic digestion by amylase, the enzyme responsible for starch breakdown. This resistance is caused by the limited accessibility of the α-1,4-glycosidic linkages in amylose’s tightly packed helical shape. But in the case of amylopectin, the presence of α-1,6-glycosidic bonds at branch points allows amylase enzymes to easily cleave the -1,4-glycosidic bonds. Because of this accessibility, amylopectin is broken down and digested more quickly, resulting in the rapid release of glucose during digestion.

Functional properties of amylose and amylopectin

Understanding the distinct characteristics of amylose and amylopectin is essential for harnessing their functionalities and leveraging them in product development and formulation.

Amylose can produce gel at concentrations above 0.9 to 1.0%, even at room temperature. This is because of its linear structure, wherein the amylose molecules. Because of its linear structure, amylose molecules can associate and form a network, resulting in the creation of firm and stable gels. These amylose gels exhibit remarkable thermal stability, remaining intact even at high temperatures of up to 248°F (120°C). This characteristic is especially essential in confectionery applications, where gels provide texture, shape, and stability to goods such as gummy candies and fruit snacks.

In contrast, amylopectin typically does not contribute significantly to gel formation. As the amylopectin content increases, the resulting starch paste becomes more viscous, albeit without the formation of a gel structure. A higher concentration of amylose promotes the formation of a stronger gel, as amylose molecules readily associate and establish chemical linkages. Only at concentrations above 10% and temperatures below 41°F (5°C) does amylopectin have the potential to form gels. However, the gelation process is slow, and the resulting gels are thermoreversible. So they melt when exposed to temperatures between 104°F (40°C) to 140°F (60°C), similar to starch gels.

In some processes where the starch must exhibit stability throughout the product’s expected shelf life, starch may be modified. Specific modified starch varieties enhance the stability of products during various processes. An example of such modified starch is the “waxy” corn variety. This is a starch that has minimal or no amylose content and a higher concentration of amylopectin. So it does not readily form networks or meshes. As a result, it imparts improved resistance to congealing and separation when cooled. Thus, it is suitable for sauces and gels. Additionally, waxy starches prevent liquid leakage or the formation of watery residue when products are defrosted, addressing a common issue associated with high-amylose starches.

Both amylose and amylopectin have the ability to modify the viscosity of foods. They improve the mouthfeel and texture of sauces, gravies, soups, and desserts. But amylopectin’s branching structure improves water-binding capability, resulting in greater stability and texture in a variety of food formulations.

References

M. Gibson (2018). Food Science and the Culinary Arts. Academic Press.

P. Cheung, B. Mehta (2015). Handbook of Food Chemistry. Springer.

J. deMan, J. Finley, W. Jeffrey Hurst, C. Y. Lee (2018). Principles of Food Chemistry (4th edition). Springer.

. Provost, K. Colabroy, B. Kelly, M. Wallert (2016). The Science of Cooking: Understanding the Biology and Chemistry Behind Food and Cooking. John Wiley & Sons, Inc.

S. Damodaran, K. Parkin (2017). Fennema’s Food Chemistry (5th edition). CRC Press.

N. A. Michael Eskin, F. Shahidi (2013). Biochemistry of Foods (3rd edition). Academic Press.

V. Vaclavik, E. Christian (2014). Essentials of Food Science (4th edition). Springer.

The post The Key Difference Between Amylose and Amylopectin appeared first on The Food Untold.

Denaturation of protein is a common occurrence during food preparation and cooking. Proteins are large, complex molecules composed of chains of amino acids folded into distinct 3D shapes. In this state, they are called native folded protein, and are able to perform their specific biological functions. But when they are denatured, they lose their functions. Denaturation is a process that disrupts the structure of a protein, causing it to lose shape and function.

Denaturation in the context of food is frequently brought on by heat, acidity, or mechanical agitation. As an illustration, when an egg is cooked, the heat causes the egg white’s proteins to denature and coagulate, resulting in the formation of a solid mass. This is similar to how milk denatures and coagulates when exposed to acid, such as vinegar or lemon juice, to form curds.

Denaturation can affect the value of foods in both good and bad ways. Proteins in meat, for instance, become denatured during cooking in order to make them more digestible. Protein breakdown can also result in the release of new flavors and aromas. The extent of these changes is determined by the type of protein in the food as well as the degree of denaturation.

But excessive denaturation can also lead to nutrient loss and changes in texture and flavor. In some instances, the food can no longer be accepted as an ingredient. When frozen egg yolks are thawed, they become lumpy and unpalatable because their lipoprotein has denatured and aggregated.In protein drinks, high protein solubility and dispersibility are necessary. Hence, partial protein denaturation during processing may cause flocculation and precipitation during storage, affecting the product’s sensory attributes.

Understanding the science behind protein denaturation is therefore critical for optimizing food quality and nutritional value.

Let’s discuss further.

WHAT IS PROTEIN DENATURATION?

The intricacy of many food systems makes it unsurprising that denaturation is a complex process that is not easily explained in simple terms. Denaturation of proteins involves the alteration of their structure, causing them to lose their shape and function. This can occur when proteins are subjected to heat, acid, or other environmental factors. Denaturation of a protein leads to its inability to perform its original function, and this can result in changes to the texture and flavor of the food it is in. For example, enzymes, which are a type of protein, lose their catalytic ability and become inactive when they are denatured.

Here is what exactly happens during denaturation of protein.

When a protein becomes denatured, there is a change in its secondary, tertiary, and/or quaternary structure. Its primary structure is not altered. Hence, there is no breaking of the peptide bonds. Peptide bonds are chemical covalent bonds that connect amino acids in a protein chain. Peptide bonds are extremely strong and stable, and they play an important role in protein stability and function. A protein chain’s backbone is made up of a repeating sequence of peptide bonds, which give the protein its distinctive shape and stability. When the protein is denatured, it does unfold, but the amino acid sequence remains the same.

When hydrogen bonds, ionic bonds, or hydrophobic interactions within a protein are broken by a treatment, denaturation occurs. Denaturation can often be reversed if the denaturing agent stabilizes the protein in its unfolded state, allowing the protein to refold back to its native conformation when the agent is removed. However, denaturation can also be irreversible if an unfolded protein is stabilized by interaction with other protein chains, such as with egg proteins during boiling.

FACTORS THAT AFFECT PROTEIN DENATURATION IN FOOD

Various factors can cause protein denaturation. Some of these factors include: heat, freezing, pH change, ionic strength change, and surface changes.

Heat

Denaturation is typically the result of mild changes. Hence, mild heat treatments such as pasteurization or blanching can induce protein denaturation..

Meat proteins are denatured at temperatures ranging from 135°F (57°C) to 167°F (75°C), which has a significant impact on the texture, water holding capacity, and shrinkage. The native proteins in meat keep the tissue moist after cutting or grinding. When heated, the proteins denature and have fewer interactions with water. The juices that leak from a cooked steak are mostly water that is no longer retained by myosin proteins. Resting a steak after cooking allows some of the water to find new interactions with proteins, resulting in less juice leaking out when the steak is cut.

Heat usually causes a change in the tertiary structure, resulting in a less ordered arrangement of the polypeptide chains. But there are exceptions to this.

Milk casein and gelatin are proteins that are quite heat stable. And they can be heat treated without apparent change in their stability. Casein’s exceptional stability makes it possible to boil, sterilize, and concentrate milk without causing coagulation. The restrictions against the formation of a folded tertiary structure explain the heat stability of these proteins. The relatively high proline and hydroxyproline content in the heat stable proteins is what causes these restrictions.

The likelihood of inter- and intramolecular hydrogen bonds forming is higher in peptide chains lacking proline than in chains with numerous proline residues. This demonstrates how the secondary and tertiary protein structures, which in turn are in charge of the protein’s functionality, are directly related to the amino acid composition of proteins.

Freezing

Protein denaturation can occur not only during thermal processing of foods, it also occurs at low temperatures. Exposing food to freezing temperatures ranging from 32°F (0°C) to 5°F (-15°C) also induces denaturation of proteins. Muscle proteins are more susceptible to denaturation than plant-derived proteins. At low temperatures, ice crystals form, which can rupture cell membranes, followed by denaturation due to surface phenomena at the interface of the two phases (protein solution and ice crystals), or possibly due to the freezing of water required to maintain the protein’s native conformation.

One way to minimize denaturation is freezing the food at a fast freezing rate, which is usually achieved by industrial freezers.

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In this manner, the interior moisture of the cell is rapidly cooled, resulting in the formation of small ice crystals, usually spearlike and separated by proteins, inside the cell. As a result, there is less dehydration and damage to proteins. Slow freezing, in contrast, often results in dehydration and an increase in the cell’s ionic strength. Water drawn from the cell’s interior will freeze onto the already existing extracellular ice crystals, causing them to grow and distort and damage the membrane and proteins.

In the fish industry, cryoprotectants such as polyols or antioxidants are applied prior to freezing. Doing so helps preserve protein stability and functionality during freezing and storage.

pH change

pH is an important element that can influence protein denaturation in food. The pH of a food product can influence the charge of the amino acid residues within a protein molecule, which affects the shape, stability, and function of the protein. When the pH of a food changes, the protein molecules might change shape, resulting in protein denaturation.

When proteins in food are exposed to acidic conditions, such as those present in citrus fruits or vinegar, they may denature. Because of the acidic environment, the protein molecules unfold, losing their functional structure and rendering them incapable of performing their intended function. However, in some cases, such as when making cheese, this is beneficial.

In cheese manufacturing, milk is often acidified by using lactic acid bacteria, which convert lactose (a sugar in milk) to lactic acid. The pH of milk decreases as the lactic acid concentration increases, causing the casein proteins to become less soluble and coagulate. The coagulation process separates the solid curds from the liquid whey, which is necessary for the creation of cheese.

This acid-induced protein denaturation also adds to the distinct texture and flavor of various cheeses. Fresh cheese, for example, is prepared by boiling milk and acidifying it with vinegar or citric acid. Because of the acidity, the proteins denature and produce small, fragile curds that are separated from the liquid whey. Hard, aged cheese, on the other hand, goes through a longer acidification process, resulting in more extensive protein denaturation and a firmer texture and sharper flavor.

Ionic strength change

Ionic strength refers to the concentration of ions in a solution, which can be increased by adding salt. The ionic strength of a solution affects protein denaturation by altering the strength of electrostatic interactions between protein molecules. Generally, increasing the ionic strength of a food can reduce the extent of protein denaturation. This is because high ionic strength solutions weaken electrostatic connections between protein molecules, thereby reducing their ability to denature and aggregate.

Salts can be utilized to induce protein denaturation and gel formation in various food processing applications, such as meat curing. Salts increase the ionic strength of the solution in certain circumstances, resulting in more extensive protein denaturation and aggregation. This can result in the production of a gel-like structure, which is desired in some processed meat products.

Surface changes

Surface change can influence protein denaturation by changing the interactions between proteins and their surroundings. Proteins have several interfaces that allow them to interact with water molecules, other proteins, and other molecules in their surroundings. These surface interactions can affect the protein’s stability and structure.

One example of surface change is brought about by altering the hydrophobicity (ability of a substance to repel water) of the protein surface. Proteins have hydrophobic and hydrophilic surfaces that influence how they interact with water molecules and other proteins. The presence of specific chemicals or changes in the polarity of the environment might modify the hydrophobicity of the protein surface, reducing its stability and leading to denaturation.

Changing the polarity of the protein can also influence protein denaturation. The presence of particular solvents or changes in pH can alter the charge distribution on the protein surface, influencing the strength and specificity of electrostatic interactions between proteins and other molecules.

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The most commonly observed surface change in food is the process of beating egg whites. Egg whites contain a globular, water-soluble protein called albumin. When eggs are beaten, the albumin molecules unfold, exposing their hydrophobic amino acid residues to the air. This allows the albumin molecules to incorporate air into the mixture. As a result, the protein becomes more hydrophobic, creating a new surface area that can interact with other hydrophobic amino acids on nearby protein molecules. These protein networks stabilize the air bubbles and prevent them from escaping, resulting in a stable foam structure. This foam structure is useful for making cakes, meringues, and soufflés due to its high volume and light texture.

APPLICATIONS OF PROTEIN DENATURATION IN FOOD

Protein denaturation is better understood from a food manufacturing perspective, as the food industry relies on manipulating proteins to produce desirable food products. However, it is also important during cooking and food preparation, as it occurs almost every time. Denaturing protein during cooking makes meat more palatable and easier to digest. In food manufacturing, protein denaturation occurs during various processes. Here are a few examples:

One of the most common applications of protein denaturation is cheese manufacturing. Adding an acid during the cheese-making process denatures the proteins in milk, resulting in the formation of curds. After being separated from the liquid whey, the curds are utilized to manufacture a variety of cheese products. Milk protein denaturation is critical for cheese formation and is tightly monitored to ensure consistent quality and product characteristics.

Protein denaturation is also essential in the creation of foams like whipped cream or meringue. Proteins must denature and form a network capable of stabilizing air bubbles in order to build a stable foam structure. Controlling the quantity of protein denaturation during foam generation is crucial for getting the optimum foam texture and stability. Mixing time, temperature, and pH can all influence the extent of protein denaturation and, as a result, the end product’s quality.

Protein denaturation is also used in the manufacturing of emulsions such as mayonnaise and salad dressings. Emulsions are often created by blending oil and water, which do not mix naturally. Denatured proteins, on the other hand, can stabilize the emulsion by enveloping and stabilizing oil droplets in a water-based solution. The emulsion’s stability is affected by a number of parameters, including the type and concentration of proteins used, as well as pH and temperature.

References:

M. Gibson (2018). Food Science and the Culinary Arts. Academic Press.

V. Vaclavik, E. Christian (2014). Essentials of Food Science (4th edition). Springer.

P. Cheung, B. Mehta (2015). Handbook of Food Chemistry. Springer

J. Provost, K. Colabroy, B. Kelly, M. Wallert (2016). The Science of Cooking: Understanding the Biology and Chemistry Behind Food and Cooking. John Wiley & Sons, Inc.

J. deMan, J. Finley, W. Jeffrey Hurst, C. Y. Lee (2018). Principles of Food Chemistry (4th edition). Springer.

H. Belitz, W. Grosch, P. Schieberle (2009). Food Chemistry (4th Edition). Springer

The post Food Chemistry: What Is Denaturation of Protein? appeared first on The Food Untold.

Cotton candy is a popular sugar-based confection. It was invented in the late 19th century and called ‘fairy floss’ by its inventors, American dentist William Morrison and confectioner John C. Wharton. Josef Lascaux, another dentist, coined the term ‘cotton candy’ during the 1920s. National Geographic discusses its history in more detail. Cotton candy is a light and fluffy treat that is a staple at fairs, carnivals, and amusement parks. How cotton candy is made requires some fascinating science.

When you look closely, cotton candy is simply spun sugar, heated to form a liquid sugar mixture. However, the trick lies in how the sugar is heated and spun to generate those light and airy threads. In addition to sugar, food coloring and flavoring can be used to create a variety of colors and flavors, making it appealing to kids and kids at heart.

In a nutshell, cotton candy is made by melting sugar and spinning it through small holes in a cotton candy machine, and allowing it to harden into delicate strands. This method is based on science of sugar crystallization.

In this blog post, we will explore the scientific process behind how cotton candy is made.

HOW IT IS MADE?

The process of making cotton candy begins with heating and melting the sugar. A cotton candy maker or spinner is the machine used to manufacture cotton candy. A heating element in the spinner melts sugar or a sugar-based combination into a liquid form. The spinning drum also helps to distribute the heat evenly, preventing the sugar from burning. If you wish to make cotton candy, a candy temperature should help. In practice, the temperature for cotton candy making is at least 260°F (127°C).

Once the sugar has melted, it is ready to be spun into cotton candy. The spinning drum has minute holes to allow liquid sugar to flow out. The sugar is spun at high rates in the machine, causing it to be drawn into long, thin strands. Then, the strands are gathered to form a larger mass of cotton candy.

This can be collected on a spinning cone, a bowl, or wooden stick, where the strands continue to build up until the desired amount is achieved.

Colors and flavors

Cotton candy’s colors and flavors are created using food coloring and flavorings, which can be combined with the melted sugar before it is introduced into the spinning chamber. Natural and synthetic food colors are available, with synthetic food dyes being the most typically utilized. These dyes are designed to be stable. Hence, they will not degrade or fade over time, allowing the cotton candy to retain its brilliant color.

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Colors can vary depending on the manufacturer and the market they are targeting. In the United States, pink and blue cotton candy is frequently linked with carnivals and fairs. Whereas green and purple cotton candy may be more popular in other countries or areas. Often, food color is based on the flavor profiles of the cotton candy. Blue cotton candy, for example, could be flavored with blue raspberry, while pink cotton candy could be flavored with strawberry.

THE SCIENCE BEHIND COTTON CANDY MAKING

The science of making cotton candy relies on precise temperature and moisture management to achieve the desired texture. It starts by melting sugar, requiring precise heating to transform it from a solid into a liquid state.

To create the thread-like consistency of finished cotton candy, the process of sugar crystallization must be carefully controlled. Several factors influence the formation of sugar crystals, including the temperature of the sugar solution. The temperature must be high enough to melt the sugar, but not so high that it completely breaks down into its component parts, glucose and fructose. Maintaining a dry environment is also crucial during the process to avoid clumping in the finished cotton candy. Even slight moisture can cause the sugar to stick together instead of forming the delicate, thin strands that make cotton candy unique.

As the melted sugar is spun out through the machine’s tiny holes, it is exposed to air, which rapidly cools it down. This rapid cooling prevents large crystals from forming and encourages the creation of small, delicate fibers of sugar, each about 50 microns in diameter.

In addition to sugar crystallization control, the spinning process provides a distinct physical structure in cotton candy strands. Cotton candy’s fluffy texture is created during the spinning process. The spinning motion’s centrifugal force causes the sugar to be stretched and tugged into thin, fragile strands, forming a network of interconnected strands. This structure contributes to cotton candy’s fluffy, cloud-like appearance. Without spinning, the melted sugar would be too dense and heavy to generate the fine, delicate strands.

The post The Sweet Chemistry: How Cotton Candy Is Made appeared first on The Food Untold.

Certain gum products are exudates produced in response to injury by plants primarily found in Africa and Asia. “Exudates” refer to gums that are released or exuded in reaction to damage to plant tissue. They produce highly tough, shiny nodules or flakes that can be harvested when exposed to the atmosphere. Gums are complex heteropolysaccharides, and gum Arabic (also called gum acacia) is an example.

Gum Arabic is the dried exudate of the acacia tree. It is a polysaccharide salt that contains ions of calcium, magnesium, and potassium. It is neutral or slightly acidic. Gum Arabic is employed in a wide range of industries. It is mostly utilized in the production of food, where it serves as a functional ingredient. It is one of the few gums that, in order to increase viscosity and serve as an emulsifier and crystallization inhibitor, requires a high concentration. Gelatin and numerous other proteins combine to generate coacervates with gum Arabic.

As a food additive, it is denoted by the E number E414. It is also used in manufacturing of hairsprays, face masks, and setting lotions, among others.

Since it can form a gel, it helps emulsify liquids, improve mouthfeel, or encapsulate flavor molecules. This is why softdrinks contain gum Arabic—it binds the sugar so it is uniformly distributed, and not precipitate to the bottom of the can.

Let’s further discuss.

HOW IT IS MADE

Sudan, Chad, and Nigeria are the two most significant growing regions for species that provide the best gum. In fact, according to the Food and Agriculture Organization of the United Nations, the three African nations control 95% of the world’s production of gum Arabic. Gum Arabic is frequently made in the form of a purified, spray-dried product.

Gum Arabic is the resin that seeps from tree stems and branches of acacia tree. The gooey, sticky material dries on the branches to form hard nodules. Production of the gum starts by carefully removing portions of the bark without harming the tree. The hardened saps are then harvested by hand and sorted according to size and color. This is the traditional way of harvesting produces the best gum.

Since the gum is made by extracting the tears from the gum tree, some gum has particles of bark in it. Because of this, the gum can absorb the bark’s color and astringent flavors. Furthermore, sand from the desert frequently contaminates raw gum. There is a need to purify the gum to remove bark and sand, especially if it is to be used as an ingredient in food. Filtering and centrifuging help removes insoluble materials. Filtration and centrifugation are effective separation techniques in the manufacturing industry.

After eliminating the contaminants, the gum is gently heated and dissolved in water to get a solution that contains between 30% and 50% gum. Acacia gum is far more soluble than other gums. If necessary, a 50% solution in cold water can be made. The viscosity of the solution decreases as the temperature rises, and is pH-dependent. Viscosity is at its highest at pH 6, although it decreases between pH 9 and below pH 4.

Forms of gum Arabic

Gum Arabic comes in several forms: raw, powder, kibbled, and spray-dried.

The raw form of gum Arabic is used in the manufacture of wine and confectionery. It is the form that has gone through simplest form of preparation—sorting and visual inspection only.

kibbled gum Arabic is gum in granular form. This is also used in wine and confectionery. Gum Arabic in powder form is also used confectionery by dusting the manufacturing surface.

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Spray-dried gum, which is commonly used nowadays, also provides pharmaceutical manufacturers with a clean, ready-to-use product. However, the price of instant gum is higher. If a confectionery company employs gum as a minor ingredient, the capital and labor costs of purifying the raw material may be extremely expensive. A company that uses gum Arabic as a major component, on the other hand, may reach a different result.

GUM ARABIC CHEMISTRY AND FOOD

Gum Arabic is a heterogeneous substance that is made up of two major components. One is formed of polysaccharide chains with little or no protein, and accounts for around 70% of the gum. The other portion has greater molecular weight compounds with protein as an intrinsic part of their structure.

In terms of protein composition, the protein-polysaccharide fraction is diverse. The polysaccharide structures are covalently connected to the protein component by coupling to hydroxyproline and, possibly, serine units. These are the two major amino acids of the polypeptide. Other amino acids includes proline, aspartame, and threonine. The overall protein content is roughly 2% by weight, but can have up to 25%. Polysaccharide structures, whether coupled to protein or not, are highly branched acidic arabinogalactans with the approximate composition:

• 44% d-galactose
• 24% l-arabinose
• 14.5% d-glucuronic acid
• 13% l-rhamnose
• 1.5% 4-O-methyl-d-glucuronic acid

Gum Arabic dissolves readily when stirred in both hot and cold water. Except for gums that have been purposefully depolymerized to produce low-viscosity kinds, it is unusual among food gums due to its great solubility and low solution viscosity. Due to their high viscosity, most gums cannot dissolve in water at concentrations greater than 5%, but Gum Arabic can produce solutions that are up to 50% concentrated. Concentration above this, dispersions are gel-like. Gum Arabic is soluble in aqueous ethanol up to a limit of around 60% ethanol, but is insoluble in oils and the majority of organic solvents.

Gum Arabic as an emulsifier

Emulsifiers are food additives that reduce liquid’s interfacial tension, allowing one liquid to spread more easily around another. A gum must have anchoring groups that have a strong affinity for the surface of the oil and a molecular size large enough to cover the surfaces of dispersed droplets in order to have both an emulsifying and an emulsion stabilizing effect.

Gum Arabic is a good emulsifier and emulsion stabilizer for flavor oil-in-water emulsions. It is the preferred gum for emulsifying citrus oils, other essential oils, and imitation flavors used as concentrates for soft drinks and baker’s emulsions. The soft drink industry in the United States consumes around 30% of the gum supply as an emulsifier and stabilizer. The protein fraction is responsible for the gum’s emulsification capabilities. Without gum Arabic, the sugar would settle to the bottom of the soda container and eventually crystallized.

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Gum Arabic has a high surface activity and produces a thick, sterically stable macromolecular coating surrounding oil droplets. Emulsions containing flavor oils and gum Arabic can be spray-dried to produce non-hygroscopic dry flavor powders that protect the flavor oil from oxidation and volatilization. Other characteristics include rapid dispersion and taste release without impacting product viscosity. These stable flavor powders are utilized in a variety of dry package products, including cakes, beverage, cake, pudding, dessert, and soup mixes.

In confectionery

More than half the world’s supply of gum Arabic is used in confections. You find it in toffees, caramels, pastilles, and candies. Gum Arabic is highly compatible with high concentrations of sugar. It prevents sucrose crystallization, emulsifies fatty components, and stops blooming in chocolates.

Sucrose crystallization affect the desired texture and mouthfeel of the finish product. One way to interfere with this process is through the addition of another ingredient whose molecule differs from the molecules that make up the crystals. These ingredients include corn syrup, dairy products, lipids, acid, gels, and gums, such as gum Arabic.

In chocolates, gum Arabic is effective in inhibiting the formation of blooming. Blooming is the white coating that form on the surface of chocolates. This either caused by the behavior of sugar or fat. The latter is due to the polymorphic transitions of cocoa butter lipids.

Another use of gum Arabic is as glaze or coating of pan-coated candies. Tempered chocolate can be poured or spray-coated onto confectionery centers, then built up in layers and finished with a hard glaze or polished with a 50% gum Arabic solution. This panning technique is comparable to that used for hard coatings.

For hard coatings, a sweetened solution, referred to as “wetting,” is added to the centers at a rate of 10 to 15% of their weight. This forms a hard coating around the centers as it crystallizes in layers. This process is also known as “engrossing.” To prevent oil seepage during storage, nuts is first wrapped with a gum arabic/wheat flour mixture.

References:

S. Damodaran, K. Parkin. (2017) Fennema’s Food Chemistry (5th edition). CRC Press.

W. P. Edwards (2000). The Science of Sugar Confectionery. The Royal Society of Chemistry.

P. Fellows (2000). Food Processing Technology (2nd edition). CRC Press.

J. deMan, J. Finley, W. Jeffrey Hurst, C. Y. Lee (2018). Principles of Food Chemistry (4th edition). Springer

The post Gum Arabic And Its Uses In Food (E414) appeared first on The Food Untold.

When talking about cheeses, most people think about cheddar, Swiss, American, mozzarella, or Parmesan cheese. These types of cheese have one thing in common—they taste and smell good. So there is no wonder why they are the most commonly eaten. In the United States, the most popular cheese is Cheddar, according to a poll conducted by Yougov. 1 for every 5 Americans or 19% prefer the cheese that originated from Somerset, England. Came in 2nd at 13% preference is Uncle Sam’s own American cheese, and 3rd (9%) is mozzarella cheese, which was followed closely by Swiss cheese (8%).

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Now where is the Limburger cheese? Is it surprising? Limburger, Muster, and other similar cheese types are known for their undesirable smell, to many, at least. This pronounced stench that Limburger cheese gives off is because of a certain bacteria involved during the ripening process.

Well, aged cheeses involve certain microorganisms during the ripening process that provide the distinct characteristics of the final product. Take the Swiss cheese for example. The production of Swiss cheese involve cultures of Propionibacterium shermanii. During cheese ripening, the propionibacteria consume the lactic acid of cheese to produce acetic and propionic acid. Along with the acid is carbon dioxide, the gas responsible for the characteristic eyes of Swiss cheese.

In the case of Limburger cheese, the bacteria responsible for the pungent smell are Brevibacterium linens. Although the bacteria make the cheese smell like rotting, they would not make anyone feel ill. An aversion to the odor of rotting has the apparent biological benefit of keeping us safe from food illness. So it is no surprise that a food made from an animal that smells like shoes or soil takes some getting used to.

BREVIBACTERIA IN LIMBURGER CHEESE

The surface growth of B. Linens are a necessary condition for the creation of the distinctive color, flavor, and aroma of smear surface-ripened cheeses, Limburger cheese particularly. Brevibacteria are smear bacteria that are natives of salty environment (up to 15% salt concentrations). These salty conditions inhibit the growth of most other microorganisms. Brevibacteria also grow in warmer conditions, and grow optimally at temperatures between 68°F (20°C) and 86°F (30°C). However, they do not withstand acidic environments well, unlike most finishing bacteria. They grow well at neutral pH and pH between 6.5 to 8.5.

When used for producing Limburger cheese, one key point cheese makers have to know is that the bacteria are an obligate aerobic bacteria—they require oxygen to grow. For this reason, the bacteria are introduced into the cheese during the ripening process by wiping it with a salt brine. This is unlike cheeses that are ripened by lactic acid bacteria, which are nonaerobic or aerotolerant microorganisms.

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The presence of Brevibacteria at the surface lead to excessive lipolysis and proteolysis. Lipolysis is the breakdown of lipids and fats, producing fatty acids, whereas as proteolysis is the breakdown of proteins.

HOW BREVIBACTERIUM LINENS PRODUCE THE SMELL

The breakdown of fats and proteins on the surface is what makes Limburger cheese distinct from most cheeses. Lipolysis and proteolysis form several carboxylic acids, such as volatile 3‐methylbutanoic, butanoic, and hexanoic acids. These acids give off aromas which are very similar to those of sweaty feet or gym socks smell.

The reason for this is because another Brevibacteria habitat of these bacteria is the human skin. And if you are wondering, they are the same bacteria responsible for body and foot odor. Our feet, when salty, sweaty, and moist just become the perfect place for them to thrive.

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It is said that the human skin is most likely the original source of the culture. Well, yes, it is possible that a cheese maker ate a cheese after growing it in a salty, warm, and oxygenated environment. This was probably how the bacteria were transferred from skin to cheese. Besides, this was how most foods we consume today started.

Other aroma molecules responsible for the smell of Limburger cheese include methanethiol and methyl thioacetate. Methanethiol is a very volatile molecule with a characteristic odor that is characterized as or “rotten egg-like” or”cabbage-like”.

The post The Bacteria That Make Limburger Cheese Smell appeared first on The Food Untold.

Our ancestors enjoyed breads without leavening them. They were basically made of cooked mixture of flour and water, and often added with salt. Today, unleavened breads still do exist. However, there is no denying that people consumed more leavened baked products. The process of leavening occurs when the gluten structure or air spaces is filled with a leavening agent, making the dough or batter to rise and expand during baking. Although carbon dioxide is the primary cause of leavening, other gases, such as ammonia gas, water in the form of steam, and integrated air (added during mixing), also contribute to the expansion of baked goods.

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Leavening can be considered the key step in bread making. Without leavening agents, doughs and batters would be dense and low in volume, resulting in dense baked items. Hence, the aeration in the crumb structure greatly contributes to the sensory assessment and consumer acceptability of bread.

Leavening agents or leaveners are categorized in three forms:

1. Biological
2. Chemical
3. Physical (mechanical)

Let’s discuss each of them.

BIOLOGICAL LEAVENING AGENTS

The biological process of fermentation may produce leavening, in which the bacteria or yeast works to metabolize organic materials that are fermentable.

Bacteria

Lactobacillus sanfrancisco bacteria is an example of this. L. sanfrancisco is a lactic acid bacteria
(LABs), which are a class of gram-positive bacteria that can transform organic acids from carbohydrate sources into a wide variety of metabolites. Organic acids, such as propionic, formic, acetic, and lactic acids, make it difficult for pathogenic and spoilage microorganisms to develop.

Lactic and acetic acids are particularly important during fermentation because they are responsible for producing sourness in sourdough bread.

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Making sourdough bread require the presence of yeast and bacteria in a ratio of about 1:100. When L. sanfrancisco is used, it if often along with Saccharomyces exiguus, a non-baker’s yeast. Depending on the type of flour and the country, different lactic acid bacteria predominate in sourdoughs. Other LABs that may be used in sourdough include Lactobacillus sakei, Leuconostoc mesenteroides, Lactobacillus paracasei, Leuconostoc citreum, and Weissella cibaria.

During fermentation, the bacteria break down maltose, releasing carbon dioxide and acetic and lactic acids in the process which adds taste in the form of sourness, while the yeast produces carbon dioxide that leavens the dough. The yeast breaks down the by-products of lactic acid fermentation, but the lactic acid bacteria can break down carbohydrates that the yeast cannot.

It is usual practice to save starters or sponges of dough from one baking and utilize them in another. These starters or sponges contain both yeast and bacteria.

Yeast

Yeasts are eukaryotic, unicellular microorganisms that belong to the fungi kingdom. Yeasts can be distinguished from bacteria by having larger cells and having cell morphologies like oval, elongate, elliptical, or spherical. Typical yeast cells have a diameter of 5 to 8 μm, while some are significantly larger. Smaller cells are more common in older yeast cultures. The majority of yeasts used in food production split through budding or fission.

Saccharomyces cerevisiae is the most common strain of yeast in making bread. Since ancient times, fermented cereal-based goods have been made using S. cerevisiae. The evolution of the modern baking industry was significantly influenced by its domestication and widespread proliferation.

The Latin name, Saccharomyces cerevisiae, means brewer’s yeast. In the fermentation process that creates bread dough, yeast consumes the starch and sugar found in flour. And it transforms them into carbon dioxide and alcohol. In an anaerobic process, it releases zymase, which breaks down fermentable carbohydrates into ethanol and carbon dioxide (the amount of carbon dioxide produced increases as the number of yeast cells increases). The majority of the alcohol is then volatized in baking, and the carbon dioxide provides the leavening action.

Baker’s yeast comes in three forms: active dry, rapid-rise, and quick yeast. They are most frequently used at home. All of these forms are available in dried form, which is advantageous for home bakers as they have 1 to 2 years of shelf life in the refrigerator.

Commercial bakers frequently use fresh or wet yeast because it is more effective, but it only has a shelf life of two weeks, making it less suitable for home bakers. However, the addition of warm water or milk and the baking process provide the heat and moisture that the yeast requires to become active (for heat).

CHEMICAL LEAVENING AGENTS

Chemical leaveners are intriguing since they start working almost instantly when added to a recipe. In situations where a lengthy biological fermentation is either unfeasible, unneeded, or undesirable, chemical leaveners are substituted instead. Baking soda is a typical chemical leavening agent.

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Baking soda

It is sometimes referred to as sodium bicarbonate or bicarbonate of soda, is a “base” that easily combines with acids to produce carbon dioxide gas. The most common sources of acids added to a baking soda leavened quick bread or muffin are buttermilk or sour cream (lactic acid), molasses (acetic, propionic, and aconitic acid), lemon juice (citric acid), or cream of tartar.

Combining baking soda with an acid, and a liquid activates it. This kick starts a reaction that produces millions of tiny carbon dioxide in the batter or dough.

The acid not only aids in the production of carbon dioxide, but also works to neutralize the combination to prevent the unpleasant taste of alkalinity from lingering in the finished product (basicity). Therefore, it is important that only the exact amount of baking soda is added as specified in a recipe.

Another thing to remember when working with baking soda is that it reacts quickly with heat and carbon dioxide when incorporated alone. It may escape even before it is able to leaven the batter. Therefore, in order for baking soda to be beneficial, it must be mixed with another ingredient. To delay the carbon dioxide production and prevent it from escaping, either a liquid acid (lemon juice) or a dry acid (cream of tartar) plus liquid should be added.

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Baking powder

Baking powder is another chemical leavening agent. But unlike baking soda, baking powder is a complete leavening agent—it already contains a base and acid to do its job. To put it simply, an acid is no longer necessary because the acid is already built into the mixture. Baking powder begins to function upon contact with a liquid.

Baking powder consists of three components: sodium bicarbonate (baking soda), one or more a dry acid (such as cream of tartar), and inert cornstarch filler. Cornstarch is there as a filler to keep the dry acid and base physically separate from one another. The filler also absorbs excess moisture in the air to prevent caking and/or reduction of its potency.

There are two types of baking powder: fast or single acting powder, and slow or double-acting baking powder

Fast/single acting baking powder produces carbon dioxide as soon as water is added. Hence, a flour mixture made with it should be handled fast and correctly and placed in the oven as soon as possible. Any delay gives the carbon dioxide time to escape, reducing the mixture’s capacity to rise. For each cup of flour, about 1 1/2 to 2 tablespoons of single-acting baking powder is required.

Double-acting baking powder, on the other hand, is slow-acting. This is what most commercial bakers use in their products. Most common are sodium aluminum sulfate and phosphate powder. It releases carbon dioxide twice: first when moistened (in a mixing bowl) and second when heated (in the oven). For each cup of flour, approximately 1 to 1 1/2 teaspoon of double-acting baking powder is necessary.

Cell walls may be stretched and break if too much baking powder is added to a formulation because of an overstretched, collapsed structure and the release of carbon dioxide bubbles.

PHYSICAL (MECHANICAL) LEAVENING AGENTS

The simplest technique of leavening is physical leavening, which includes adding air to a batter or dough mechanically or physically.

Air or steam

Almost all batters and doughs contain some amount of air, which when heated expands and adds to the product’s volume. In “unleavened” baked goods, such as some breads, crackers, or pie crusts, it could be the only leavening agent.

There are several ways to incorporate air as a leavening agent during baking. Creaming sugar and fat, together can add air to a cake. Creaming incorporates air by beating sugar crystals and solid fat (usually butter) in a mixer. This occurs because sugar crystals are capable of physically dissolving through the structure of the fat. As air becomes trapped by the web of sugar and fats, air pockets are created, adding volume to the final baked product. Often, creamed mixtures are further leavened using a chemical leavener, usually baking soda.

Another way to physically leaven using air is by beating egg whites or whole eggs. This is often done when making angel food or sponge cake. Due to their ability to foam when forcefully beaten or whisked, egg whites can leaven baked goods. This is due to the egg white’s capacity to hold air, which is what gives it its function as a leavening agent. The volume of whipped egg whites can grow by up to eight times. This leavening is made possible by albumin and ovalbumin, two proteins found in egg whites. This post further explains this.

Steam

The conversion of water to steam is a physical change, thus, steam is a physical leavening agent in baking. Nearly everything is leavened to some extent by steam. Steam vapor is produced in 1,600 parts for every part of water. Water, juices, milk, or eggs are examples of liquid components that can be used to create steam. Foods such as cream puffs, choux pastry, and popovers rely on steam for leavening. The dough protein expands as a result of the creation of steam, and the egg protein denatures and coagulates to give them their distinctive high volume and hollow interior.

Sometimes steam is injected into the oven at the start of baking. This is to make sure the bread rise higher and the crust is thinner.

References:

M. Wallert, K. Colabroy, B. Kelly, J. Provost (2016). The Science of Cooking: Understanding The Biology And Chemistry Behind Food And Cooking. John Wiley & Sons, Inc..

V. Vaclavik, E. Christian (2014). Essentials of Food Science (4th edition). Springer.

M. Gibson (2018). Food Science and the Culinary Arts. Academic Press.

J. Jay, M. Loessner, D. Golden (2005). Modern Food Microbiology (7th edition). Springer.

W. Zhou, Y. H. Hui, I. DeLyn, M. A. Pagani, C. M. Rosell, J. Selman, N. Therdthai (2014). Bakery Products Science and Technology (2nd edition). John Wiley & Sons, Ltd

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