Sodium metabisulfite is a chemical compound commonly used in the food industry for several purposes, so individuals might seek information about it. Sodium metabisulfite is a relatively common food additive, but many people are not familiar with what it is or how it is used. Searching online can be a good way to learn more about this additive and its potential effects on health. So if you are one of those who are curious about it, this blog post will guide you.
Let’s jump right in.
Table of Contents
WHAT IS SODIUM METABISULFITE?
Sodium metabisulfite, a white or yellowish-white crystalline powder with a pungent sulfur odor. In Europe, it is denoted by the E number E 223, when used as a food additive. It is a chemical compound with the formula Na2S2O5. Its molecular structure endows it with unique properties and reactivity.
One notable characteristic of sodium metabisulfite is its high solubility in water. When introduced to water, it readily dissolves, forming sodium bisulfite (NaHSO3) and releasing sulfur dioxide gas (SO2). The release of SO2 is responsible for the compound’s pungent sulfur odor, making it easily identifiable.
Chemically, sodium metabisulfite is classified as a reducing agent, meaning it can donate electrons to other substances. This property is central to its various applications.
In water treatment, it is utilized to reduce or eliminate chlorine and chloramine, thus making it valuable for dechlorination purposes. It is used in ore processing to reduce metals like gold and silver. In photographic development, it serves as a reducing agent to convert silver ions into metallic silver, aiding in image formation.
Within the food industry, sodium metabisulfite serves dual purposes as both a preservative and an antioxidant. Its pivotal function involves thwarting the browning of fruits and vegetables by impeding both enzymatic and non-enzymatic browning reactions. Additionally, it contributes to maintaining the color, flavor, and texture of diverse food items, all the while suppressing the proliferation of microorganisms that could cause spoilage.
FUNCTIONS IN FOOD
Sodium metabisulfite serves multiple functions in the food industry, including as a preservative to extend shelf life, an antioxidant to maintain color and flavor, and a bleaching agent to lighten the color of certain food products.
Let’s discuss in more detail.
Bacterial inhibitor in beer, ale, and wine
Sodium metabisulfite is a widely used chemical compound in the winemaking and brewing industries. Its role is particularly significant in the production of wine, ale, and beer. As a strong antimicrobial agent, sodium metabisulfite helps to control and prevent bacterial growth during the fermentation and aging processes. This ensures the quality and stability of these alcoholic beverages.
In winemaking, the control of bacteria is crucial for achieving the desired flavor and aroma profiles. Undesirable bacteria can lead to off-flavors and spoilage, which can ruin a batch of wine. When added to grapes, sodium metabisulfite inhibits vacterial growth by releasing sulfur dioxide (SO2) gas. This SO2 gas acts as a powerful antimicrobial agent, inhibiting the growth of unwanted bacteria, yeasts, and molds. This ensures that the wine fermentation proceeds with the selected yeast strains and prevents spoilage that could negatively impact the final product.
Similarly, in the brewing of ales and beers, the presence of bacteria can lead to the development of off-flavors and turbidity in the beer. By adding sodium metabisulfite, bacterial growth is inhibited. This ensures that the chosen yeast strains dominate the fermentation process and produce a consistent and desirable beer flavor.
Antifermentative agent in sugar and syrups
As a powerful inhibitor of fermentation, sodium metabisulfite helps prevent unwanted microbial growth and the conversion of sugars into alcohol or organic acids in sugar and syrup solutions.
In the sugar industry, the prevention of fermentation is essential to maintain product consistency. Microorganisms such as yeasts and bacteria can metabolize the sugars in syrups. This can lead to changes in flavor, texture, and the development of off-flavors. Sodium metabisulfite is added to sugar solutions to create an unfavorable environment for these microorganisms, inhibiting their growth and metabolic activity.
Syrup manufacturers also use sodium metabisulfite to extend the shelf life of various syrup-based products. Fruit syrups, corn syrup, and flavored syrups often contain sodium metabisulfite. By preventing fermentation, the antifermentative properties of sodium metabisulfite help maintain the sweetness, texture, and overall quality of the syrups over time, preventing them from becoming sour or alcoholic.
The usage of sodium metabisulfite as an antifermentative agent requires careful consideration of dosage and monitoring to ensure the desired effect is achieved without negatively impacting the taste or safety of the product. Excessive use of sodium metabisulfite can lead to an undesirable sulfur dioxide taste or create allergenic concerns, so precise control is essential.
Antibrowning additive in cut fruits, dried fruits, peeled potatoes, and maraschino cherries
Sodium metabisulfite is a widely used antibrowning additive in the food industry, particularly in products such as cut fruits, dried fruits, peeled potatoes, and maraschino cherries. Browning in these foods occurs due to enzymatic reactions when they are exposed to oxygen. The discoloration not only affects the visual appeal but can also alter the taste and overall quality of the food. Sodium metabisulfite serves as an effective solution to counteract these undesirable browning reactions.
Cut Fruits: When fruits are cut or sliced, they are particularly prone to browning due to the release of enzymes like polyphenol oxidase. By adding sodium metabisulfite to cut fruits, food processors can inhibit these enzymes and prevent the browning process. This is especially important for fruit platters, salads, and other dishes where the presentation is vital.
You might also like: Enzymatic And Non-enzymatic Browning
Dried Fruits: During the drying process, fruits can undergo browning reactions, which impact their appearance and flavor. Sodium metabisulfite is used either as a pre-treatment or as a preservative in dried fruits. It not only maintains the natural color but also extends the shelf life of products like apricots, apples, and raisins.
Peeled Potatoes: Peeled and sliced potatoes are staples in many dishes, but they are highly susceptible to browning, which can affect their visual appeal. Sodium metabisulfite is applied to these potato products to inhibit enzymatic browning, ensuring they remain appetizing in appearance.
Maraschino Cherries: Maraschino cherries are preserved in a syrup or brine solution. Sodium metabisulfite is introduced into the preserving liquid to prevent cherries from browning and to maintain their bright red color. This not only preserves their visual appeal but also their characteristic flavor.
SAFETY CONSIDERATIONS
To ensure the safe utilization of sodium metabisulfite, global regulatory authorities have instituted maximum permissible limits for its inclusion in food products. In the United States, the U.S. Food and Drug Administration (FDA) recognizes sodium metabisulfite as generally safe (GRAS) when employed in adherence to good manufacturing practices.
In the European Union, the European Food Safety Authority (EFSA) established a temporary group acceptable daily intake (ADI) of 0.7 milligrams per kilogram of body weight per day in 2016. However, in 2022, EFSA issued a subsequent evaluation regarding the safety of sulfur dioxide-sulfites. The conclusion indicated that the uncertainties identified in the 2016 reassessment had not significantly diminished. Consequently, EFSA withdrew the temporary group ADI, determining that the available toxicity database lacked adequacy to derive an ADI for sulfur dioxide-sulfites.
Allergies and Sensitivities
A key safety concern linked to sodium metabisulfite revolves around its capacity to induce allergic reactions in specific individuals. Sulfites, including sodium metabisulfite, have the potential to trigger sensitivity or allergies in some people. Allergic responses may manifest in mild symptoms like skin rashes, itching, and hives, while more severe reactions such as difficulty breathing and, in extreme cases, anaphylaxis can occur.
individuals with known sensitivities or allergies to sulfites should exercise caution and be aware of potential adverse reactions when exposed to products containing sodium metabisulfite.
Asthma and Respiratory Issues
Individuals with asthma or other respiratory conditions may be more susceptible to adverse effects from sodium metabisulfite. Sodium metabisulfite is toxic in inhalation. Inhalation of the compound’s fumes or dust particles could irritate the airways and trigger asthma attacks. Food processing facilities that handle sodium metabisulfite should have proper ventilation systems and take necessary precautions to minimize the release of sulfite fumes into the air.
