Course:FNH200/Projects/2024/Citric Acid v. Sodium Propionate in Slowing Bacterial Spoilage

Citric Acid v. Sodium Propionate in Slowing Bacterial Spoilage

Introduction

Additives in Canada are described as any substances expected to affect the characteristics of a food and/or beverage, either directly or through its by-products. Additives extracted from plants, minerals, or animals are considered natural, while chemical additives are the result of a chemical or enzymatic reaction. Citric acid, a naturally occurring additive in lemons, exemplifies the divide between the perceptions between natural and chemical counterparts such as Sodium Propionate. The food and beverage industry also commonly uses the synthetic form of citric acid which can be produced from molds or fermented sugar, but for our purposes, we will be comparing the use and effects of the natural form of citric acid. It is often perceived that natural additives are safer than their chemical counterparts, but this is not always the case. Understanding the science behind additives may help clarify misconceptions and address the safety and efficacy of the additives. We aim to explore the differences in citric acid (natural) and sodium propionate (chemical) by evaluating their abilities to inhibit bacterial growth and preserving foods and beverages.

Citric Acid

An Overview

Citric Acid Powder and a Lemon

Citric acid is an organic acid once primarily extracted from lemons, but modern commercial use appears more commonly as extract citric acid from carbohydrate fermentation or mold. The two different forms (anhydrous and monohydrate) of citric acids are versatile and can be used in foods, detergents, pharmaceutical applications, as well as personal care products, as it acts as a naturally occurring antioxidant. In the food and beverage industry, anhydrous citric acid is favoured and primarily used as an acidulant to sterilize, stabilize bacteria, fixate flavour, enhance flavour, and standardize acidity levels.

Citric acid is odourless, colourless, and highly soluble in water. The acid both enhances tangy flavours in foods while retaining the food’s quality through its metal ion sequestering properties, preventing oxidation which otherwise would cause flavour and colour loss.

Citric Acid Chemical Structure

Anti-bacterial Function

Citric acid is classified as a relatively weak acid because of its partial solubility in water. Though, citric acid has low pH levels between 3 and 6, classifying it as a high acidity additive. At the cellular level, the acid’s low pH levels interact with cell membranes, causing damage to DNA, protein, and extracellular membranes, leading to bacterial death.

Limitations

While citric acid is generally considered a safe food product in Canada, preservatives are known to trigger allergic reactions, and excessive amounts may promote tooth decay over time. On the other hand, citric acid does contribute nutritional value by aiding in energy metabolism and mineral absorption.

Sodium Propionate

An Overview

Sodium Propionate Powder

Unlike citric acid, sodium propionate is chemically synthesized by neutralizing propionic acid with sodium hydroxide. Sodium propionate is often used as a preservative in commercial meat products and baked goods to prevent the growth of mold and some bacteria. Like citric acid, sodium propionate can have other pharmaceutical applications but is more commonly used as a preservative.

Anti-bacterial Function

Its water solubility allows it to function as a mold inhibitor as it has a pH range of 2-5.5, reducing mold growth similarly to citric acid. It has a slight cheese-like flavour, though is colourless and mostly odourless.

Sodium propionate Chemical Structure

Limitations

Though sodium propionate is also generally considered a safe food product in Canada, some emerging evidence suggest high levels of exposure to sodium propionate can increase blood glucose, cholesterol, and triglyceride levels, profoundly affecting the brain's dopamine system. Damage to the brain’s dopamine system can potentially induce depressive symptoms.

Safety

According to the EFSA Panel of Food additives and Nutrient Sources added to food (ANS), it is safe to use sodium propionates in preparing meat and processed meat (including fish) up to 5,000 mg/jg.

Comparison

Effect on Meat Products

The use of sodium propionate in ground beef, for instance, has been shown to both increase shelf life by reducing microbiological growth and negative flavours related to lipid oxidation. Citric acid used in meat products such as surimi and restructured fish products show a significant increase in brightness, firmness, gumminess and suitability. In addition, citric acid can provide positive effects when incorporated into tenderized meat. For instance, hen meat with citric acid significantly increased the meat’s water carrying capacity, reduced liquid loss, and decreased cooking weight loss by retaining moisture throughout the cooking process.

Effect on Baked Goods

Citric acid and sodium propionate both function to extend the shelf life of baked goods. Heat during the baking process causes the hydrolysis of sorbitol palmitate, which releases sorbic acid, which then interacts with citric acid and sodium propionate to achieve longer shelf life. Citric acid can also impact other physical properties in the baking process such as increasing the meltability and firmness of baked mozzarella cheese. Considering that the texture of bread crumbs is valued by consumer, it is important that citric acid has also been shown to have a make crumbs softer in bread made from spelt. In addition gluten can be strengthened by citric acid by which hydrogen anions in acid combine with negative portions of amino acids altering the protein charge.

Conclusion

Throughout our research, we can conclude that citric acid and sodium propionate have similarities despite being natural and chemical additives respectively. Both are equally capable of inhibiting bacterial and mold growth, and preserving food and beverage items, as well as sterilizing, stabilizing bacteria, fixating and enhancing flavour, and standardizing acidity levels. We often perceive natural additives, citric acid in this case, as superior to their chemical counterparts, such as Sodium Propionate. Though in reality, both are equal in its risks and rewards, depending on the individual. Citric acid contributes positively through its anti-bacterial capabilities, improvements to meat texture such as increased brightness and suitability, while aiding in metabolism efficiency and mineral absorption. Sodium Propionate is chemically synthesized and used in meats and baked goods to prevent the growth of mold and certain bacteria, increasing shelf life and preserving flavors otherwise overshadowed through lipid oxidation. As for drawbacks, Sodium Propionate yields the possibility of increased blood glucose, cholesterol, and triglyceride levels, whereas citric acid can trigger allergic reactions and tooth decay. Depending on the individual’s health status, negative aspects can be weighted and assessed, and consumption decisions can be made accordingly. Overall, these two substances can be used interchangeably in terms of its preservation use through their acidic approach to suppressing mold and bacteria growth. These preservatives’ role in extending the shelf life of products such as meat and baked goods are integral to our everyday lives, and whether the additive is natural or chemically derived poses limited risk with greater reward.

Exam Question

Which of the statements best described the differences in antibacterial functions of citric acid and socium propionate in food preservation?

(a) Citric acid is a strong acid that directly kills bacteria by breaking down its DNA. Sodium propionate only inhibits mold growth by altering the . pH.

(b) Citric Acid is effective in baked goods by altering the protein charge. Sodium propionate is more effective in meat products by reducing microbial growth and lipid oxidation.

(c) Sodium propionate enhances the flavour of foods. Citric acid is used to prevent bacterial growth in means and baked goods.

(d) Both citric acid and sodium propionate work best in the same pH range and are equally effective in both meat products and baked goods.

Correct answer: (a)

Why should the question be in the final exam?

Our question identifies the role of citric acid and sodium propionate by linking their functions to baked goods and meat. It should be on the final exam because citric acid and sodium propionate are commonly used additiives in the food industry. By asking this question in the final exam, we are learning real-world topics that are directly relevant to food safety and science.