Читать книгу Food Chemistry. The Role of Additives, Preservatives and Adulteration онлайн

97 страница из 126

 iii. Anti-browning agent: The development of brown or gray or black color in food product is due to browning reaction that may be of two types.a. Enzymatic browning that makes the formation of quinones by the oxidation of polyphenols in presence of polyphenol oxidase. It can be prevented by blanching, acidification, and addition of sulfites.b. Non-enzymatic browning occurs due to the reaction between reducing sugar and free amino acids resulting melanoidin pigment. It can be prevented by avoiding excessive heat, controlling moisture content, and application of sulfites. Sulfites are used in the form of sodium (or potassium) sulfite, bisulfite, or metabisulfite. Other anti-browning agent includes ascorbic acid, cysteine, and 4-Hexylresorcinol.

Nutritional additives mean addition of pure compounds like vitamin, mineral, amino acid, and fatty acid to maintain or improve the nutritional quality of food. It is also added for other purposes, like vitamin C and E are added as antioxidant, and carotenoids are added to improve color.