Ingredient photostability as affected by iron: Colorant degradation

Abstract

Composition and storage parameters affect the chemical stability of foods and beverages. Temperature, water activity, oxygen levels, pH, buffer salts, carbonyl compounds, and minerals are some of the variables that influence chemical reactions within the food (Bell, 2007). Vitamin degradation, color loss, and flavor changes are examples of unwanted chemical reactions that may occur in food products. These chemical changes will consequently lessen the product's quality and shelf life. Understanding ways to minimize the rates of these reactions is, therefore, an important aspect of food product development. The food industry has utilized artificial colors for decades. Colors certified for food use by the Federal Food, Drug and Cosmetic Act are classified as FD&C colors (Francis, 1999). Some examples of FD&C colors include Brilliant Blue (FD&C Blue No. 1), tartrazine (FD&C Yellow No. 5), and Allura Red (FD&C Red No. 40). In his overview of colorant stability, Francis (1999) noted tartrazine and Allura Red have good stability in acid and upon light exposure; Brilliant Blue also has good stability in acid but slightly lower stability when exposed to light. Degradation of the colorant would result in the gradual fading of the respective color until complete decolorization occurs, resulting in food quality being compromised. The degradation of rebaudioside A, a natural sweetener, is another reaction that can lessen a food's shelf life. Zhang and Bell (2017) noted that rebaudioside A degradation in solution was enhanced by exposure to ultraviolet (UV) light. Further investigations found that degradation occurred faster in the presence of iron (Toohey & Bell, 2019). The fastest degradation was observed when solutions containing both citrate and iron were exposed to UV light