During the earliest days of making bread, the ingredients that bakers would use are relatively simple—flour, salt and yeast. The practice of using yeast to make bread rise started as early as 1300 BC. During this period, bread is eaten within days without the need for longer storage. This was the case for most consumers until the Industrial Revolution, which spanned from the late 18th century to early 19th century. During this period, the food industry shifted from manufacturing by hand to using machine. And later on, bread products started to contain preservatives to extend their shelf life. Today, one of the most commonly in bread is calcium propionate.

What is it? Is it a safe ingredient?

Let’s find out.

What is calcium propionate in bread?

Calcium propionate is a compound used in bread and other baked products as a preservative. In Europe, calcium propionate is denoted by the E number E282. It is particularly effective as a mold inhibitor. Hence, it is often used in high moisture baked products.

Chemically, it is the calcium salt of propionic acid, the same type of organic acid made during production of certain cheeses and butter. Calcium propionate chemical formula is C₆H₁₀CaO₄. It appears as a crystalline powder or in granular form. Calcium propionate’s compatibility in baking lies in its solubility and stability. It is soluble in 49 g per 100 CC water. This solubility allows for even distribution throughout the dough. Calcium propionate is also stable under normal baking as well as high temperatures. For this reason, its antimicrobial properties do not degrade after baking and during storage.

Calcium propionate is made by neutralizing propionic acid with a calcium such as Calcium Carbonate or Calcium Hydroxide. The propionic acid can be sourced either by fermentation processing using bacteria, usually Proiponibacterium, or by oxidizing ethylene.

How it works

Like most preservatives, calcium propionate prevents the growth of bacteria, molds, and other microorganisms that cause food spoilage. And it is particularly effective against molds, particularly species like Penicillium and Aspergillus. They thrive well in moist and warm areas.

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Calcium propionate works mainly by disrupting the metabolic processes, which are essential for growth and development in microorganisms. Calcium propionate achieve this by releasing propionate ions. These ions hinder with nutrient uptake and energy production that slows down microbial activity. Aside from this, the ions also create an acidic environment further interrupt normal cellular functions in microorganisms.

Is calcium propionate a safe ingredient?

Calcium propionate a safe ingredient for bread and other baked products. In fact, the Food and Drug Administration (FDA) has classified it as “generally recognized safe” (GRAS). Similar responsible authorities, including the European Food Safety Authority (EFSA) and the World Health Organization (WHO) have also regarded it as a safe ingredient. Their judgment is based on available studies and scientific evidence. This means calcium propionate has been reviewed thoroughly and does not pose a risk to human health when consumed at levels typically used in food. As a mold inhibitor, calcium propionate is used at levels between 0.1% and 0.4% of the product weight.

While calcium propionate is generally safe to consume, there are rare cases reported about individuals who experienced minimal side effects such as headache, abdominal discomfort, and allergic reactions. The exact cause of this is not completely understood. However, these side effects are more often experienced by individuals with existing sensitivity or allergy to certain preservatives. You may also experience these symptoms with excessive intake. But again, such cases are very rare.

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Calcium propionate, like most food components, is metabolized by the body once ingested. The human body breaks it down into calcium and propionic acid. Now, these two components are not foreign matters to the human body. And they are naturally obtained from consuming certain foods such as cheese, butter, and other fermented foods.

The propionic acid derived from calcium propionate is metabolized by the liver and converted to energy, whereas calcium, as we all know, is a nutrient essential for maintaining healthy bones and teeth.

Conclusion

So, there you have it. Calcium propionate is in your bread as a preservative. It particularly works in inhibiting the growth of molds and other spoilage microorganisms.

While the name maybe intimidating, Calcium propionate is a safe ingredient in bread and other baked products. Various regulatory bodies have approved it for use as a food additive. And while this is true, it is worth noting that some individuals might experience headache, abdominal discomfort and other minimal side effects. This is more likely to occur to individuals with existing sensitivities or those who intake calcium propionate-containing food excessively.

If you are really concern about this, I suggest consuming fresh-baked bread from your nearby bakery. Store-bought breads are likely to contain preservatives, including calcium propionate.

The post Why Calcium Propionate Is In My Bread? appeared first on The Food Untold.

Philosopher Aristotle coined the idea of the spontaneous generation theory in 4th century BCE, 22 centuries before time of Louis Pasteur. This theory stated that living matter could arise from non-living matter spontaneously. One of the most famous examples of this theory is that maggots could appear on decaying piece of meat.

This idea went on to persist for a very long time. This is due largely to the fact that it easily explained how mold grow on bread or that flies appear on spoiled food.

But this idea did not align to many scientists, many of them tried to disprove this idea, including Louis Pasteur.

Early challenges to spontaneous generation

For a millennium, Aristotle’s theory of spontaneous generation was widely believed around the world. Was this because of the lack of technology that science enjoys today? For example, microscopes were far from being invented to allow researchers to observe and study microorganisms. Hence, experiments to test theories were not really much of a thing back then.

By the 1600, scientists and scholars have started questioning the factualness of the theory. One of these individuals who challenged the theory was Italian physician Francesco Redi. He showed that maggots do not spontaneously arise from decaying meat by doing the so-called “Redi experiment” in 1668.

In this experiment, Redi set up 3 jars of various conditions. The first jar was open and let flies to enter the jar. The second jar was tightly to prevent flies from entering. And the last jar was covered with a mesh. After letting the jars sit for a short period, maggots appeared in the open jar and mesh-covered jar, but not the tightly sealed one.

Redi concluded that flies laid eggs that would hatch into maggots. This result suggested that living matters like maggots come from other living matters, and do not arise spontaneously. Although the Redi experiment demonstrated that living matters could only arise from pre-existing living matters, this was not sound enough to disprove the spontaneous generation theory.

Hence, the debate continued.

Antonie Van Leeuwenhoek contribution

Antonie Van Leeuwenhoek was a Dutch scientist known as the Father of Microbiology. He developed microscopes during the 17th century that were considered advance during that time. Leeuwenhoek made about 500 microscopes in this career. One of these could magnify objects up to 300 times. This capability was unrivaled back then. In comparison, the microscope English physicist Robert Hooke developed could only magnify up to 50 times. This magnification could only reveal basic details on minute organisms.

Leeuwenhoek’s, on the other hand had greater magnification. This allowed him to study various microorganisms in greater detail. Leeuwenhoek described bacteria, yeasts, and other microorganisms. Their shapes, movement, and behavior were documented for the first time. But his discovery of the existence of microorganisms was not solid evidence to dispel the spontaneous generation theory.

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When his work was made public, scientist still wondered the same question. Do microorganisms come from pre-existing living things? Or they just generate spontaneously from non-living things? Yes, the scope of microbiology back then was very limited. However, Leeuwenhoek’s contribution to understanding microorganisms paved the way for another scientist to disprove the theory of spontaneous generation at once, Louis Pasteur.

Louis Pasteur’s works prior to debunking the spontaneous generation theory

Louis Pasteur was a French chemist and microbiologist. He lived during the 19th century. At this point, the debate on the spontaneous generation theory was at its peak. Prior to disproving the theory, he already worked on fermentation, and pasteurization.

In 1850s, Pasteur studied extensively the process of fermentation. Fermentation is a preservation method wherein sugar in food is converted into alcohol or acid. Prior to Pasteur’s research on the process, it was widely accepted that fermentation was solely a chemical process. The belief was that fermentation would occur because components in food decompose in the absence of air. Hence, microorganisms were not believed to be responsible in fermentation.

But Pasteur’s work changed this when he studied spoilage in wine and beer. In the mid-19th century, the brewing industry in France was suffering from economic losses due to spoilage of wine. The losses were massive that it hit wine exports badly. To resolve the problem, Napoleon III and the French government asked for help from Pasteur. He then presented clear evidence that undesirable or spoilage microorganisms were responsible for the off-flavor and souring in wine.

What Pasteur did was preheat the wine at between 122°F (50°C) and 140°F (140). This prevented souring and extended the shelf life of wine.

Based on his research on microorganisms, spoilage microorganisms found in wine are heat sensitive. Hence, he hypothesized that treating the wine with elevated heat high enough to destroy these microbes would effectively extend the shelf life of wine. The temperature range he used was well thought of because not only it killed unwanted microbes, but it was also not high enough to preserve the flavor of the wine. This heat treatment is now called pasteurization.

Pasteur’s Swan-Neck Flask experiment debunked the spontaneous generation

Louis Pasteur became aware of the spontaneous generation when he came to know fellow Frenchmen Felix Archimède Pouchet, a strong follower of the spontaneous generation theory. Pasteur had been very skeptical about the theory, and the French Academy of Sciences opened a competition called Alhumbert Prize to ultimately put an end to this debate. Pasteur took up the challenge and performed an experiment that would ultimately debunk the theory— the Swan-Neck flask experiment.

In this experiment, Pasteur gathered a number of long, curved S-shaped flasks that looked like swan’s neck, hence the name of the experiment. He filled each flask with an infusion or nutrient rich broth. After that, he pasteurized the flasks to destroy the harmful microorganisms that were present in the broth.

After letting the pasteurized broth in the flask to sit for some time he observed what happened. And just as he predicted, the broth did not change in appearance or appear to have been contaminated. The unique S-shape of the flask prevented contaminated to happen here. The curve neck allowed air to flow through, but not dust and any other elements that may contaminate the broth.

But if the curved long neck of the flasks were removed, or the flask were tilted that the broth got into contact with the curve neck, airborne microorganisms would have been introduced to the broth and contaminate it.

The Swan-Neck flask experiment by Pasteur ultimately debunked the spontaneous generation theory. Because of this, he was awarded the Alhumbert prize, which also carried a value of 2,500 francs. This was considered a huge sum already in 1862.

The post How Louis Pasteur Debunked the Spontaneous Generation Theory appeared first on The Food Untold.

Karl Busch, a German scientist, invented the method of vacuum packaging during the 1950s. He first used this in packaging technology to extend the shelf life of meat products. During this period, vacuum packaging only serves as a means to extend the shelf life of food that individuals would consume during the days of war. A decade later, Busch introduced a machine that would allow manufacturers to vacuum pack food products in an industrial scale.

Today, vacuum packaging is one of the common methods of packaging food. Its wide range of applications include fruits and vegetables, dried fish, meat, and dairy products. In many households, a small home vacuum sealer can be used to vacuum pack leftovers.

Let’s discuss vacuum packaging in more detail.

What is vacuum packaging?

Vacuum packaging is a type of food preservation method that involves modifying the atmosphere inside the packaging―it particularly removes air or oxygen. Hermetically sealing the package results in a near-perfect vacuum. This packaging technology uses a highly flexible plastic packaging that molds to the contour of the product being packaged.

Vacuum packaging is based on the principle of air (oxygen) removal inside the food packaging. A wide range of microorganisms, from bacteria to fungi, require various things to live—including oxygen.

Microorganisms can be classified according to their oxygen requirements—aerobic and anaerobic. Aerobic microorganisms are those requirement air to grow, whereas anerobic microorganisms are those that can tolerate the absence of air. Both of these types can be found in foods and spoil them. So, by removing air, food can be preserved and extend its shelf life.

And since anerobic microorganisms can also be found in food vacuum packaging is often partnered with another type of preservation method to make it more effective. This is the reason why some vacuum-packed foods like pasta, frozen meals, and seafood, in the supermarket are put in display freezers.

Dried nuts, dried fruits, and cured meats in vacuum packaging, on the other hand, are shelf life stable because in addition to the lack of oxygen, the products are also low moisture and contain high concentration of sugar/salt. Hence, they can be placed at room temperature.

In addition to removing air available for microbial growth, vacuum packaging also controls the oxidation of fatty acids that results in rancidity in food. As the name suggests, oxidation occurs in the presence of oxygen. If present, it reacts with unsaturated fats that is commonly found in nuts, meats, and other similar products. This is what causes off flavor, off odors and other undesirable changes in food.

How does it work?

Vacuum packaging is the final step in the production process for most products. As much as possible, this is completed immediately to minimize exposure to elements, particularly air.

To do this, the food that has undergone the final process is placed in a suitable packaging. The packaging material should be impermeable to various external elements, including air and moisture. Commonly used for vacuum packaging include nylon, Polypropylene (PP), Polyethylene (PE), Polyester (PET), laminated films, and aluminum foil.

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With the product inside the packaging, it is brought inside a vacuum packaging chamber. This device can suck the air and oxygen out of the packaging by up to 99.8%. An effectively vacuum-packed container produces a skintight wall appearance. Thus, there should be no air pockets, especially along the edges.

After turning the packaging into a vacuum, the pack is closed by heat sealing or pulse sealing.

Special considerations

Vacuum packaging can be a good option as one way of food preservation. In general, vacuum-packed food stored can last from 6 months up to 2 years at freezing temperatures, and 1 or 2 weeks at refrigeration temperature.

Although this is the case for most products, there are several considerations when using vacuum packaging. For example, vacuum packaging should only be used for food that does not support the growth of Clostridium botulinum. This is because this bacterium is an anaerobic―it can survive inside a vacuum packaging.

Cl.botulinum is a bacterium that produces botulinum toxin, one of the most toxic substances known, and is commonly associated with improperly canned food products. Ingesting botulinum-contaminated food may result in paralysis or death.

As earlier mentioned, the storage temperature for vacuum-packed food should at refrigeration of at least 45°F (7°C) or lower. This should be maintained at all times. Anaerobic pathogens or disease-causing bacteria, including Cl.botulinum, are capable of increasing their growth rate exponentially as the temperature increases. Placing vacuum-packed foods at low temperatures not only slows their growth rate down, but it also inhibits toxin production.

Perhaps the best way to prevent food illness as a result of ingesting contaminated vacuum-packed food is to have the product shelf life to not exceed 10 days. The storage temperature requirement is best to be prominent on the package. And the shelf life determined by the initial processor should not be extended. This is particularly important for meat, seafoods, and other perishables.

Is the packaging compromised?

The common signs that a food has already spoiled include off odor, off flavor, discoloration, and undesirable texture (slimy, for example). In the case for vacuum packaging, its appearance can tell if something is already going bad.

A proper vacuum packaging is tightly sealed, skintight, and it contours to the product. For this reason, bulging or bloating inside the package can easily be seen. Bulging inside a vacuum packaging is concerning because it could be caused by gas produced by bacteria. Yes, microorganisms can produce gas bubbles, which is a byproduct of their metabolism. This is the same way yeast like Saccharomyces Cerevisiae produce bubbles during fermentation. But in this case, gas bubble might be caused by harmful microorganisms, particularly Cl.botulinum.

The post What Is Vacuum Packaging In Food Preservation? appeared first on The Food Untold.

Ohmic heating, also called Joule heating, is one of the few food processing methods that uses electricity. James Prescott Joule discovered that electricity gives off heat, and this heat is produced from resistance (ohms) in 1841. To put it simply, electricity is converted into heat energy. This discovery has led to believe that this process can be used to process and preserve food.

This has turned into fruition when Ohmic heating was used to pasteurize milk in the late 19th century. The process involved flowing milk between two plates of different electric voltages. At the turn of the 20th century, progress in Ohmic heating was considerably limited though.

This was due to various reasons, mainly technological constraints (lack of suitable electrode materials), lack of the understanding of the process, and financial considerations. In 1930s, the process was called “Electro-Pure”. In the 1950s, a process of sterilizing milk using Ohmic heating was developed. However, the process was discontinued because of the high operational costs and the excessive use of electricity.

Interest in Ohmic was revisited in the 1980s because there was a need for a process that could efficiently sterilize liquid–large particle mixtures. Today, Ohmic heating has become an attractive option for food manufacturing. This is in large part of the unending research and study about the technology.

Let’s discuss Ohmic heating further.

What is Ohmic heating?

Ohmic heating is a food process wherein electric current is converted into heat energy to heat the food. It is also known as Joule heating, electrical resistance heating or resistance heating, and electro-heating. A Ohmic heating device commonly consists of a power source, an electrode, and a way to contain the sample, a vessel or tube, for example.

Ohmic is performed by passing alternating current (AC) or direct current (DC) to the food material placed between electrodes. As the electricity hits the food, salts, water and other components resist this energy and generates heat.

This food process is based on the principle of electrical resistance. Electrical resistance is the measure of how resistant a material is to the flow of electric current. In the case of Ohmic heating, the food material is the electrical resistor. The resistance depends on various factors, including the composition of the food, and the amount of moisture present.

Because of this resistance, the electric energy is dissipated and converted into heat. This heat generation is rapid that allows quicker and uniform heating of food than in thermal-based food processes. Ohmic heating is particularly effective for liquid–particle mixtures as they allow uniform heat transfer.

Ohmic heating vs conventional heating methods

Conventional thermal processing methods such as boiling, sterilization, and canning have been known to cause product quality degradation because of slow convection and conduction heat transfer.

Slow heat transfers in conventional heat treatments are fully known in the food industry. In canning, food is heated by conduction, wherein heat is transferred from one material to another. In the case of canning, heat is transferred from the can to the food. This heat transfer is slow, especially if the can is considerably larger or the food is densely packed inside.

This is where Ohmic heating is a much better option. With Ohmic, the entire food mass can be heated volumetrically. It is possible to heat large portion of food by up to 1 in.3. And since Ohmic heating can heat food rapidly, it can transfer heat to the inner portion without difficulty.

This is unlike conventional methods that sometimes overprocess the surrounding liquid portion of the food being heated as it transfers heat to the inner portion. This uneven heating diminishes quality.

In nutrient retention for example, it has been studied that food that has undergone conventional heat treatments contain lower nutrients, particularly heat-sensitive ones.

One of the findings in this study is the reduction vitamin C in food processed under Ohmic and conventional heating. In conventional heating, the product’s vitamin C reduced by 13.58%. Ohmic heating, on the other hand, was not that different from unheated sample. Another study found heating under Ohmic helps retain significantly higher antioxidant activities and essential minerals essential minerals calcium, potassium, and phosphorus.

This just suggests that Ohmic heating is better at preserving food quality, especially nutrients, than conventional methods.

Uses and applications

The first use of Ohmic heating was for sterilizing milk in the 19th century. Since then, its usage than expanded to various sectors in the food industry. It is now also used for food items such as fruit juices, purees, meat, canned goods, and vegetables.

Let’s briefly discuss some of the processes Ohmic heating is used for.

Thermal processing

Pasteurization and sterilization have long been used for processing liquid like milk and fruit juices. Pasteurization involves temperatures that destroys and reduce the levels of spoilage microorganisms, whereas sterilization destroys all microorganisms, including beneficial ones (probiotics, for example).

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Integrating Ohmic heating with these thermal processes helps rapid and uniform heating to maintain product quality. In the United States, Ohmic heating is used to produce liquid egg product.

Fermentation

Fermentation is an anaerobic process that uses microorganisms to convert carbohydrates such as sugar into alcohol. Examples of fermented products includes kimchi, yogurt, and wine.

The application of Ohmic heating in fermentation has been less common than when used with thermal processes. One beneficial use of it in fermentation is the reduction of acidity in cocoa and coffee beans. While acidity may be desirable to some varieties of coffee, reducing its levels in many varieties often results in a smoother and rounded flavor. Arabica coffee is one example of coffee that naturally contain high acidity.

This study proved that using Ohmic heating can effectively reduce this acidity to a more desirable level. The time and temperature variations used in the study resulted in acid levels between 0.18% and 0.73%.

Thawing

Food thawing may be a relatively simple step in food preparation. But doing it in a much better way can help food processors save resources and retain quality. In most cases, there would be moisture loss or drip loss. This is evident when the food is drier. Drip loss is commonly associated with meat, seafood, fruits, and vegetables.

Drip loss occurs because the ice crystals that ruptured that cell walls turns into water and escapes from the food. There is more drip loss if air thawing is done because the process is very slow. With Ohmic heating, thawing is rapid because the heat is generated from the food itself, instead from the surface inward.

Another benefit of Ohmic heating for thawing is that there is not a need for water. Hence, no wastewater is generated. This also saves resource and operating cost.

Blanching

Similar to thawing, blanching may also result in moisture loss. However, the mechanism of how it occurs is different. With blanching, the elevated temperature ruptures the cell wall of the food that allows the water to escape and nutrients to leech into the blanching water.

With Ohmic heating, it is possible to reduce or prevent moisture loss and leeching. Its rapid heat generation allows uniform heating and prevents overcooking of the surface. A study found that blanching with Ohmic heating also removes the need of cutting (a process that is commonly done prior to blanching) large pieces of food, especially vegetables. The reason here is uniform and rapid heating that traditional blanching cannot achieve. This particularly important for delicate vegetables.

Extraction

Uneven temperatures can also lead to inefficient extraction of certain components from food materials. Examples of extraction are juicing from fruits, soymilk from soybeans, and beet dye from beets.

Traditional extraction methods apply heat from the outside to the inside of the sample. Since this manner of heat transfer is relatively slow, there is an extended processing time. Not only this affects the yield, it also affects the quality of extraction. This is especially true if what involved in the extraction are heat-sensitive compounds like vitamins.

With Ohmic heating, the quality of extract is better preserved. This statement is demonstrated in this study of Ohmic heating-assisted extraction of anthocyanins from black rice bran. Anthocyanins are natural pigments responsible for the color of eggplants, blueberries, purple grapes, and cherries. Anthocyanins are heat sensitive. But with Ohmic heating used in the study, the method had better colorant yield, as well as bioactive compound activity.

References:

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

S. Rahman (2007). Handbook of Food Preservation (2nd edition). CRC Press

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

P. Zeuthen, L. Bogh-Sorensen (2003). Food Preservation Techniques. CRC Press

The post Ohmic Heating (Joule Heating) Of Food: How Does It Work? appeared first on The Food Untold.

Non-thermal based processing methods like high-pressure processing (HPP) are relatively novel techniques. Thermal-based ones have been used for the long time. But these non-thermal based techniques have been recently garnering attention in the food industry because they are able to preserve food while minimizing the loss of quality.

In this blog post, we’ll discuss the specifics of high-pressure processing. We’ll discuss how it works, its benefits, and its applications in the food industry.

What is high-pressure processing?

As the name suggests, high-pressure processing in a type of food processing method wherein extremely high pressure is used to eliminate harmful microorganisms and preserve the food. This type of processing method is innovative because it does not use heat or chemicals. The latter, in some instances, is not favorable because it can cause undesirable changes like browning or nutrient degradation. This is why high-pressure processing is desirable in certain food products like fruits, vegetables, and other perishable items.

The first high-pressure processed foods were fruits kiwi, strawberries, and apple jams, all of which produced by Meidi-ya Food Co., Japan. The color and taste of the jams was natural.

It is worth noting though that although HPP can prolong shelf life, it does not pasteurize food. That means after processing, the food must be kept at refrigeration temperature. This is especially true for low-acid foods like milk, vegetables, and soups. High-pressure processed food can last up to 120 days or 4 months.

HPP-made food products can more costly than used produced using other methods, mainly heat treatments. The factors that contribute to this include the especial packaging requirement, lower production capacity, and low market demands. All of this are which are expected for novel technologies. However, consumers may benefit from extended shelf life, quality, and the value-added products, which cannot be achieved with other processing methods.

Today, HPP is used mainly on food products with high moisture contents such as ready-to-drink meats, seafood, fruit juices, and prepared vegetables. HPP is not as effective in dry products because moisture is necessary to carry out the process.

How does it work?

HPP involves subjecting the food at extremely high hydrostatic pressure. Prior to this, the food is usually packed in a highly flexible sterile packaging container. And then, it is put in a chamber where it is pressurized. The pressure employed varies and can reach up to 87,000 lb per square inch (psi) for 3 to 5 minutes. This pressure that hits the food is uniform on all the sides. For this reason, the shape of the food is retained—not damaged or squished.

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How high-pressure processing works depends on the Le Chatelier’s Principle. According to this, any reaction or change or phase transition with an increased in volume will be favored at high pressures, and reactions that involved an increase in volume will be inhibited. However, because many food systems are complex, the changes and reactions that can occur under high pressure can be difficult to predict at times.

Fortunately, recent progress on research and study about HPP has led to knowing the various effects of high pressure on chemical and enzymatic reaction, microbial inactivation, and nutrient retention.

In terms on biological retention, for example, the membrane of the microorganism is the most probably area for disruption. Furthermore, high-pressure can also inactivate key enzymes, particularly those involved during DNA replication and transcription. The combination of these factors is lethal to vegetable microorganisms.

Why high-pressure processing?

HPP is similar to other kinds of processing methods—they destroy harmful microorganisms and extend the shelf life of various products. But as I have already mentioned, HPP can be a much better option for a few reasons.

HPP merely depends on high pressure to do its job. Hence, there is no covalent bonds that are broken during processing. When broken, covalent bonds tend to produce free radicals or chemical by-products. Free radicals are highly reactive molecules because they contain an unpaired electron. Prolonged exposure to free radical can be harmful to human health because they can damage cells and DNA.

Because HPP does not produce free radicals, HPP practitioners do not require approval from the Food and Drug Administration (FDA) and Food Safety Inspection Services to operate.

Another reason HPP can be a better option is nutrient retention. It is just one of the few non-thermal processes that do not use heat to process food. Other similar methods include osmotic dehydration, irradiation, and pulse electric fields.

HPP is particularly beneficial in processing foods that contain vitamin B, C, and antioxidants lycopene and beta carotene. These are nutrients that degrade at high temperatures. This behavior is demonstrated in this study, wherein strawberry and blackberry purees produced by HPP reduced antioxidant activity by only 5%, whereas thermally processed ones reduced by 25%.

References:

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

S. Rahman (2007). Handbook of Food Preservation(2nd edition). CRC Press.

R. Rajenran, A. George, N. Kalarikkal, S. Thomas (2019). Innovative Food Science and Emerging Technologies. CRC Press

The post High-Pressure Processing Of Food: How Does It Work? appeared first on The Food Untold.

Aluminum foil was first used in food in the early 20th century as packaging material for chewing gum and candies. Fast forward to the present, it can be used for preservation and cooking—grilling, baking, and grilling.

And yes, that answers the question—food wrapped in aluminum foil can be heated. But this depends entirely on the appliance you are working with. You can use aluminum foil in the oven and air fryer (but with caution), but not in the microwave oven.

Using aluminum foil in the oven

There are various ways you can utilize aluminum foil when working when an oven. You can either use it to a line baking sheet, as a wrapping, or a drip pan.

Aluminum foil is a great conductor of heat. It is why it is often used for in the baking to help cook the food much fast and evenly. This is particularly useful for food items that require consistent temperature all throughout the baking process.

One good example is during roasting of large cuts of meat. Due to the size, there should be consistent temperature for slow and even cooking. By wrapping the meat in aluminum foil, the moisture and heat get trapped. This allows the food to cook evenly.

While it is true that using aluminum foil in the oven is generally safe, it’s important to monitor both the cooking time and the type of food you’re preparing.

It’s advisable to limit the use of aluminum foil for shorter cooking periods. Although aluminum foil can handle high oven temperatures, prolonged exposure may cause it to react and dissolve into the food.

As for the kind of food items you should be worried about, acidic foods, such as citric fruits and vinegar may also lead to aluminum foil leeching. Temperature alone makes aluminum foil less reactive. But the presence of acidic substance such as those mention triggers a chemical reaction. This reaction dissolves aluminum foil, and elevated temperature accelerates it.

One study has found that aluminum-contaminated food may result in brain disorder such as Parkinson’s disease. So if you are going to cook something with an acidic ingredient, use an alternative such as stainless steel or glass.

Using aluminum foil in the air fryer

Aluminum foil also be placed in an air fryer the same way as in an oven. But there is a difference on how it many affect cooking. Ovens use radiant heat to cook food, whereas air fryers use hot air around the food to cook it.

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In an oven, you can easily wrap food completely. But the same cannot be done with working with air fryers. Instead of radiant heat, air fryers use hot air to cook. So while it is possible to put aluminum foil inside an air fryer, you should allow enough space to allow the hot air to circulate around the food.

If the foil blocks the flow of the hot air, the food will not be cooked properly. Furthermore, the cooking time will be longer. In some cases, the restricted air flow may cause the inside of the air fryer to overheat and cause component damage.

Using aluminum foil in the microwave

No, you really cannot use aluminum foil for cooking food in the microwave. Do not ever try. And here is why.

Microwave works differently than the first two kitchen appliances. It cooks food by emitting electromagnetic waves. These waves make the water molecules present in the food to vibrate. This vibration is very rapid that it generates heat strong enough to cook the food from the inside and out.

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While foods absorb the waves, metals like aluminum foils reflect them. And when the waves just bounce off, a strong electric force is formed between the foil and inside of the microwave. If this electric field becomes very strong, the air molecule inside become ionized. This means the molecules are broken down into charged particles, allowing electricity to cross between the foil and the microwave or to another portion of the foil. This reflection creates visible sparks inside the appliance.

This is a serious safety concern. The sparks could be in contact with something flammable inside, such as food oil, and cause fire. When this occurs, it is likely for the electronics and other essential components of the microwave to malfunction.

Conclusion

Oven and Air fryer

Aluminum foil is generally safe in ovens and air fryers (with caution). It helps cook food evenly, especially for larger cuts of meat in the oven. However, limit its use for shorter cooking times to avoid potential leaching into food. Be mindful of acidic ingredients as well. Opt for alternative materials like glass or stainless steel for acidic foods.

Microwave

Absolutely not recommended! Microwaves use electromagnetic waves that cook food from the inside out. Metals like aluminum foil reflect these waves, creating sparks – a serious fire hazard. Additionally, it can damage the microwave’s components.

The post Can Food Wrapped In Aluminum Foil Be Heated? (In the Oven/Air Fryer/Microwave) appeared first on The Food Untold.

Kimchi is a traditional Korean food made from various vegetables, usually cabbage. Its unique taste is a result from a weeks-long fermentation. If you freeze kimchi, would it be the same? Would it still be safe for consumption?

Fermentation is a preservation method wherein beneficial microorganisms consume the sugars present in food. In return, alcohol or acid are produced. In the case of making kimchi, lactic acid bacteria (LABs) convert the sugar in lactic acid. This acid is mainly responsible for the tangy and sour taste of kimchi. The initial fermentation process is usually allowed to take place for 1 to 2 days at room temperature.

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After that, the kimchi is transferred and stored at refrigerated temperature for several weeks to months. Refrigeration does not stop the fermentation process; it only slows down fermentation. This allows for the complex flavors to form. But if the kimchi has been stored in the refrigerator for an extended period, it may become strongly sour, and it is not really desirable.

Freezing kimchi for later use

This is when freezing is a great option. And yes, you can definitely freeze kimchi. Not only it prevents over fermentation, but it also extends its shelf life for roughly 1 year.

The traditional practice of storing of kimchi in Korea is either refrigeration or earthenware jar (onggi). The cool temperature involved with the two methods allow for natural fermentation of kimchi. Nowadays, the busy lifestyle in the country has changed how they store it. This is especially true for individuals who are used to making kimchi in large batches.

To prevent food waste, they would store kimchi in the freezer. If you wish to do the same, it is better that the kimchi has aged or fermented sufficiently. Remember that fermentation requires time in order for the texture, flavor, as well as nutrients to fully developed. If you store kimchi in the freezer before it reaches its maturity, fermentation stops, preventing it to reach its optimum quality.

Refrigeration temperature encourages slow fermentation, while freezing temperature stops it. The typical refrigeration temperature for storing kimchi is between 36°F (2°C) and 43°F (6°C). The freezing temperature, on the other hand, is at 32°F (0°C) and below. This lower temperature halts several reactions, particularly microbial activity.

As I have already mentioned, LABs are the main reason why kimchi undergoes fermentation. These bacteria are temperature sensitive. They thrive at room temperature and cool environments. And at freezing temperatures, they become inactive until the environment becomes tolerable again. However, the microbial population and their activity might be reduced due to stress and cell damage.

So while freezing is a safe and good option for storing kimchi for later use, make sure that it has been fermented fully. The texture, taste, and nutrients are locked once it is frozen and after thawing.

Proper freezing of kimchi

Want to make sure your kimchi is properly stored in the freezer? Here are several things you can do to.

Like any other frozen food, freeze kimchi by portions. This way, you will be able to take out the amount you only need. Frequent freezing and thawing gradually diminishes the quality of kimchi. During freezing sharp ice crystals penetrate the cells of the vegetables. Repeated freezing and thawing will repeat will ice crystal formation. Over time, the kimchi would become mushy and soft, and the flavor also is lost as a result of cell structure damage.

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To prevent this, place kimchi in airtight and freezer-safe container. You can also use freezer bags. These containers can keep air and moisture out. These and other freezer elements, when present inside the container, causes oxidation that negatively affects the texture and flavor of food.

Earlier, I said that frozen kimchi can last up to 1 year. It is true. But its quality might not be up to your liking. Most frozen foods, including kimchi, are actually good, in terms of quality for 3 to 6 months. So, you would want to consume frozen kimchi within this time frame. To make sure of it, label the container the date when it was first stored for easy tracking.

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Have you ever wondered why paraffin wax is used in certain food items such as cheese? If you did, it would not very surprising. Besides, it looks like the substance used for making candles, right? Who would dare to eat candles? Kidding aside, paraffin wax has long been used in food as a very effective packaging since the late 19th century.

It was first discovered in the 1830s by German chemist Karl von Reichenbach. Decades later, its use expanded to various industries, including food manufacturing. As you might already think, paraffin wax has been used as a food packaging materials for over a century now, and there is not a problem.

So to answer your question—is paraffin wax in food toxic?

No, paraffin wax used in food is not a toxic substance, and its food-grade—it has been processed, refined, and purified.

Let’s discuss further.

WHAT IS PARAFFIN WAX?

Chemistry

Paraffin wax is a soft, crystalline white or colorless petroleum product. It is solid at room temperature between 136°F (58°C)- 144 (62°C). As a byproduct, it is composed of hydrocarbons that form during the refining process of crude oil. Going back to basic chemistry, hydrocarbons are compounds that consist of hydrogen and carbon entirely. There are 4 classes of it: alkanes, alkenes, alkynes and arenes. Paraffin wax consists mostly of alkanes, the kind of saturated hydrocarbon wherein the hydrogen atoms are connected by a single bond between carbon atoms.

However, the actual composition of the wax depends on many factors, including the refining method and the crude oil itself. In many cases, the paraffin wax may contain traces of other hydrocarbons, including alkenes or alkynes.

In food

As I have already mentioned, paraffin wax was first made not for packaging food items—but as an aid for separating wax substance found in petroleum. It found its first main purpose in making candles. Before the discovery of paraffin wax, candle makers used tallow fat. However, the flame made from it is smoky and emits unpleasant odor.

The discovery of paraffin wax as an ideal material for making candles was a breakthrough. It creates a cleaner and brighter flame, and it is an inexpensive alternative to tallow fat.

By the early 20th century, some food items have started to be shipped out in paraffin wax. Examples of these foods, include candies, chocolates, cheese, and fruits.

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And these are for good reasons. Paraffin wax possesses moisture and oxygen-barrier properties. Moisture and oxygen are external factors that negatively affect the shelf life and quality of food. Certain types of cheeses, for example, require ample amount of moisture to retain its flavor, appearance, and texture for an extended period of time. Gouda, Cheddar, and Queso de Bola (Philippine cheese) often come enclosed in red paraffin wax.

IS PARAFFIN WAX SAFE TO EAT? IS IT TOXIC?

No, paraffin wax safe is not there for consumption. It is a no-brainer. It is just a packaging to protect the food inside. And if you did digest a small amount, it would not cause harm because it would just exit your body unchanged. A considerably amount of it is a different story though. It may result in discomfort in your digestive system.

The most apparent concern here is if paraffin wax in food is toxic. Besides, it is a food contact surface. Since I have already answered this question earlier, I will just explain why it is not a toxic substance.

Paraffin wax is a chemically inert substance—it does not react with other substances, food, in particular.

And here is why (more chemistry alert).

As we have already discussed, paraffin wax is composed mostly of (alkanes) saturated hydrocarbons. In this arrangement, the carbon atoms are bonded totally with the hydrogen atoms. For this reason, it is not possible for double or even triple bonds to form. To simply put, alkanes are unreactive type of hydrocarbons.

Furthermore, there are also no functional groups such as carboxyl and hydroxyl groups. These functional groups can readily react with other substances. because of the absence of these functional groups, there are no chances for other atoms within a molecule to interact with.

Well, paraffin wax will start a reaction if you light it up with food still inside it. But you would not do that, of course. Paraffin wax has a high energy activation requirement in order for the stable carbon-hydrogen bonds to break and form new ones.

So that is it. Paraffin wax is not a toxic substance in food.

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Silica gel packets are those small pouches often found in food, medicine, and other packaging. The common warning “Do not eat” has led many to wonder about their safety and potential toxicity. Given how often these packets appear in everyday products, it’s understandable that people have questions.

In this blog post, we will discuss what silica gel is, how it functions, its various applications, and whether it poses any health risks.

What Is Silica Gel?

Silica gel is an example of a desiccant. Desiccants are substances that have the capability to absorb and retain moisture. In many industries, silica gel is often used. It is made of silicon dioxide (SiO₂), the same compound found in quartz and sand. Its porous structure allows it to absorb water molecules from the surrounding environment. 

For this reason, it is very effective in keeping the humidity within the packaging at desirable levels. This is especially useful in preserving the quality and shelf life of various products. 

Typically, silica gel comes in the form of tiny, spherical beads or granules. These beads have a vast surface area, filled with microscopic pores that attract and trap moisture. When exposed to humid conditions, the moisture is drawn into these pores and held there by molecular forces. Because of this, there is a reduction in humidity within a sealed environment.

One of the key benefits of silica gel is that it can be regenerated and reused. After the gel becomes saturated with moisture, it can be dried out by heating it to around 392°F (200°C), a process that drives off the absorbed water and restores its moisture-absorbing properties. This makes silica gel not only effective but also sustainable for repeated use in various applications.

How Is Silica Gel Used in Food and Medicine?

Silica gel’s moisture-absorbing properties make it indispensable in several industries, particularly food and pharmaceuticals.

In food packaging, silica gel packets maintains the product quality by controlling moisture levels. Many dry foods, such as snacks, nuts, and dehydrated goods, are highly susceptible to moisture. The moisture can lead to spoilage, mold growth, and changes in texture and flavor. By absorbing excess moisture, silica gel packets help keep these products fresh and crunchy, extending their shelf life and ensuring they remain safe to consume.

For example, consider a bag of potato chips. If moisture enters the packaging, the chips can become soggy and lose their crispness. Silica gel packets prevent this by maintaining a dry environment inside the package, preserving the product’s texture and taste. Similarly, in the case of powdered or granulated foods like spices and coffee, silica gel prevents clumping and caking, ensuring that these products retain their intended consistency and flavor.

In the pharmaceutical industry, silica gel is commonly included in the packaging of pills, capsules, and vitamins. Medications are often sensitive to moisture, which can lead to chemical degradation, reducing their potency and effectiveness. For instance, vitamins and supplements can lose their efficacy when exposed to humidity, while tablets can become sticky and clump together, making them difficult to dose accurately.

Common Uses of Silica Gel in Packaging:

Are Silica Gel Packets Toxic?

Silica gel packets often are packed in packaging that says, “Do Not Eat”. But silica gel is non-toxic and chemically inert, meaning it doesn’t react with other substances and poses no health risk when handled properly. In fact, silica gel is sometimes used as a lubricating agent in certain drug formulations, underscoring its safety in small quantities.

The warning on the packet is primarily about safety rather than toxicity. The small beads can pose a choking hazard, particularly for young children and pets. This is why ingestion should be avoided. However, if accidentally swallowed, silica gel typically passes through the digestive system without causing harm. A study found that silica gel ingestion accounts for 2.1% of annual poison control calls. But most cases result in no significant health issues, with only mild discomfort in some instances.

In certain cases, silica gel packets contain a moisture indicator, such as cobalt chloride. This indicator changes color when it absorbs moisture. This feature is useful for monitoring humidity levels, as it signals when the silica gel has reached its capacity and needs replacement. However, cobalt chloride can be harmful if ingested in large amounts. So it is important to keep these packets out of reach of children and pets.

The presence of cobalt chloride does not diminish the silica gel’s effectiveness in protecting products, but it does introduce a potential risk. Therefore, it’s essential to handle these packets with care and store them in a safe place.

If a silica gel packet is accidentally ingested, it’s advisable to seek medical advice, particularly if cobalt chloride is involved. However, most cases result in minimal to no harm, and simple precautions can prevent any issues.

Conclusion

So, are silica gel packets toxic? The answer is generally no—silica gel packets are non-toxic and safe when used correctly. While the warning labels might seem alarming, these packets are generally safe when used and handled correctly. By storing products containing silica gel out of reach of children and pets, you can ensure they continue to serve their purpose without posing any risk to your household.

The post Silica Gel In Food Packaging: A Harmless Ingredient Explained appeared first on The Food Untold.

Chilling injury is a significant issue that can severely affect the quality, shelf life, and marketability of temperature-sensitive vegetables. This physiological disorder occurs when vegetables are stored below their optimal temperatures, leading to various undesirable effects, such as tissue softening, loss of flavor, the development of off-flavors, and increased susceptibility to decay.

For farmers, retailers, and consumers, understanding the causes and preventive measures for chilling injury helps maintain the quality and longevity of vegetables.

Let’s discuss this further.

What Is Chilling Injury?

Chilling injury is a type of cold damage that affects vegetables when they are exposed to temperatures below their tolerance levels but above freezing. According to the Food and Agriculture Organization (FAO) chilling injury occur at temperatures below 55°F to 60°F (13°C to 16°C).

Unlike freezing, which causes obvious ice crystal formation and severe cell damage, chilling injury can be more insidious, gradually affecting the vegetable’s quality. Symptoms include softening of tissues, surface pitting, internal discoloration, loss of flavor, and increased susceptibility to decay due to weakened cell structures.

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For instance, tomatoes stored at temperatures below 50°F (10°C) might develop an undesirable texture, and cucumbers can become water-soaked and mushy. These changes not only reduce the aesthetic appeal of the produce, but also diminish its nutritional value and taste.

Factors Contributing to Chilling Injury

Preventing chilling injury begins with understanding the factors that make vegetables susceptible to this condition. Key factors include vegetable variety, harvest maturity, storage temperature, and storage duration.

1. Vegetable Variety

Not all vegetables are equally sensitive to chilling injury. Some varieties are highly susceptible, while others can tolerate lower temperatures without significant damage. For example:

• Highly Susceptible Vegetables: Cucumbers, peppers, and tomatoes are particularly prone to chilling injury. When stored below 50°F (10°C), they may experience softening, discoloration, and loss of flavor. The texture becomes compromised, and the taste can turn bland or develop off-flavors, making them less appealing to consumers.

• More Tolerant Vegetables: Vegetables like carrots, cabbages, and potatoes are more resilient to cold temperatures. These crops can be stored at temperatures as low as 32°F (0°C) without suffering major damage. Their natural structure allows them to withstand colder environments, which is why they are often stored in refrigerated conditions without adverse effects.

Understanding the specific sensitivity of each vegetable variety is crucial for determining the appropriate storage conditions to prevent chilling injury.

2. Harvest Maturity

The stage at which vegetables are harvested plays a significant role in their susceptibility to chilling injury. Vegetables harvested either too early or too late are at greater risk:

• Early Harvest: Vegetables harvested before reaching full maturity may not have fully developed their natural defenses against cold temperatures. For instance, immature tomatoes, picked before their green color begins to change, are more likely to suffer from chilling injury, showing symptoms like pitting and a mealy texture.

• Late Harvest: On the other hand, vegetables harvested beyond their peak maturity are also vulnerable. Overripe produce, such as bananas or avocados, tends to become overly soft and develop off-flavors when stored at low temperatures. These vegetables may already be in the early stages of decay, making them more susceptible to cold damage.

Harvesting at the correct stage of maturity is critical to reducing the risk of chilling injury during storage.

3. Storage Temperature

The temperature at which vegetables are stored is the most critical factor in preventing chilling injury. Most vegetables have specific temperature ranges that they can tolerate without suffering damage. Exposing them to temperatures below these ranges can cause cellular damage, leading to:

• Tissue Softening: This compromises the texture of vegetables, making them less firm and appealing. Softened tissues are more prone to mechanical damage during handling and transport.

• Loss of Flavor: Chilling injury often results in a bland taste or the development of off-flavors, such as bitterness or mustiness. This can significantly reduce the vegetable’s appeal to consumers.

• Increased Susceptibility to Decay: Cold-damaged tissues are more vulnerable to microbial invasion, accelerating spoilage. This can lead to significant post-harvest losses, which are estimated to be as high as 25% in some cases.

Maintaining the correct storage temperature is essential to preserving the quality of vegetables and minimizing the risk of chilling injury.

4. Storage Duration

The length of time vegetables are stored at low temperatures also influences the risk of chilling injury. The longer the exposure to suboptimal temperatures, the greater the likelihood of damage:

• Short-Term Storage: Even brief exposure to temperatures slightly below the optimal range can cause chilling injury if the storage duration is extended. For example, cucumbers stored at 45°F (7°C) for more than two weeks may begin to show signs of chilling injury, such as softening and discoloration.

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• Long-Term Storage: The effects of chilling injury are cumulative. Studies have shown that vegetables stored at 35°F (1°C) for more than three weeks are at a significantly higher risk of developing chilling injury compared to those stored for just one week. As the duration increases, symptoms like increased susceptibility to decay and off-flavor development become more pronounced.

Effective Measures to Prevent Chilling Injury

Preventing chilling injury involves a combination of pre-harvest, harvest, and post-harvest practices. Here are some key strategies:

1. Pre-Cooling

Pre-cooling is a crucial step in reducing the risk of chilling injury. This process involves rapidly lowering the internal temperature of vegetables after harvest to slow down their metabolic processes. Effective pre-cooling methods include:

• Forced-Air Cooling: Air is circulated over the produce to quickly remove heat.

• Hydrocooling: Vegetables are cooled by immersion in cold water.

• Vacuum Cooling: Air pressure is reduced to allow the rapid evaporation of water, which cools the produce.

Pre-cooling to a temperature of 32-35°F (0-2°C) within 24 hours of harvest is recommended for many vegetables to reduce the risk of chilling injury.

2. Appropriate Packaging

Selecting the right packaging materials is essential for maintaining the quality and freshness of vegetables. Key considerations include:

• Breathability: Use materials like perforated plastic bags or mesh bags that allow air circulation, preventing moisture buildup and condensation.

• Moisture Absorption: Incorporate materials like silica gel packets to control humidity within the package.

• Protective Padding: Use tissue paper or bubble wrap to prevent bruising and damage during transport and storage.

• Avoid Overpacking: Ensure sufficient space between vegetables to allow proper air circulation and prevent pressure-related damage.

Following these guidelines can significantly reduce the risk of chilling injury.

3. Controlling Humidity

Maintaining optimal humidity levels is another critical factor. Humidity refers to the amount of moisture present in the air within the storage environment. It plays a critical role in preserving the quality and extending the shelf life of perishable produce.

Vegetables stored at temperatures below their optimal range can suffer from chilling injury, which can be exacerbated by improper humidity levels. Adequate humidity helps mitigate some effects of chilling injury by maintaining vegetable texture and preventing moisture loss, but it must be carefully controlled to avoid contributing to decay or mold growth.

Leafy greens, such as lettuce and spinach, require higher humidity levels (90% – 95%) to prevent wilting and dehydration, as their delicate tissues are highly susceptible to moisture loss. Root vegetables, like carrots and beets, also generally require high humidity to avoid drying out and maintain their crispness.

In contrast, bulb vegetables such as onions and garlic prefer lower humidity levels to prevent rot and sprouting, as excess moisture can lead to decay. Fruiting vegetables, including bell peppers and cucumbers, have moderate humidity needs to balance moisture retention while avoiding issues like mold or excessive moisture that can contribute to spoilage.

4. Maintaining Optimal Storage Temperature

Research the specific temperature requirements for each type of vegetable. For example, root vegetables like carrots and potatoes often require colder conditions (32°F to 40°F) compared to leafy greens or tomatoes. Temperature-controlled storage facilities or climate-controlled containers are ideal for maintaining these conditions. Regular monitoring of storage temperatures is also essential to ensure they remain within the recommended range.

6. Applying Modified Atmosphere Packaging (MAP)

Modified Atmosphere Packaging (MAP) is a preservation technique that involves altering the composition of gases within the packaging. This change in the composition of gas slows down the respiration rate and delays the ripening process of the produce. As a result, the physiological and biochemical changes that can cause chilling injury are minimized.

In the usual setting, the typical atmospheric gases—oxygen (O₂), carbon dioxide (CO₂), and nitrogen (N₂)—are adjusted to optimal levels for the specific product being packaged. For example, reducing the oxygen content can slow down oxidation and microbial growth, while increasing carbon dioxide levels can inhibit the activity of spoilage microorganisms. Nitrogen, an inert gas, is often used to displace oxygen and act as a filler gas.

Conclusion

Prevent chilling injury to vegetables can be managed through proper understanding and application of storage techniques. By considering the specific needs of different vegetable varieties, optimizing storage conditions, and using appropriate technologies like pre-cooling, MAP, and humidity control, farmers and retailers can significantly reduce the risk of chilling injury.

These measures not only help preserve the quality and freshness of vegetables but also reduce post-harvest losses, ensuring that consumers receive the best possible produce.

The post Understanding and Preventing Chilling Injury in Vegetables appeared first on The Food Untold.