Food Chemistry. Группа авторов

chelator binds with metal and prevents them from radical formation;c. quencher that inactivate high energy oxidant;d. oxygen scavenger that removes oxygen from the system;e. antioxidant regenerator that regenerates the antioxidants.Polyphenols are natural antioxidants like flavonoids, tannins, lignans, and coumarins. Natural antioxidant also includes Ferulic acid, Catechin, Ascorbic acid, Tocopherol, Carotenoids like Lycopene, and β-carotene. They are generally used as plant extracts. Synthetic antioxidants include Butylated Hydoxy Anisole (BHA), Butylated Hydroxy Toluene (BHT), tbutylhydroquinone (TBHQ), gallate, and stannous chloride [8–10].In contrast to synthetic antioxidant scientists are finding alternative source of antioxidant in nature. They found that algae contain natural antioxidative compounds that affect various pathogenic organisms with low-cost isolation process. The main antioxidant includes vitamin C and E, carotenoids, polyphenols, and chlorophyll. The red and brown algae contain high levels of folic acid and folate. Two species of cyanobacteria Spirulina platensis and Spirulina maxima are considered as supplements. They have the capacity of lowering lipid content in human body, antioxidant and anti-inflammatory effect. They have high nutritional value. They are considered as important food during long term space mission by NASA. Other important algae include Chlorella vulgaris, Phaeodactylum tricornutum, Gayralia oxysperma, Chaetomorpha antennina, Sargassum vulgare, and Chondrus crispus. They have high antioxidant capacity and have a potential to act as a source of natural antioxidant.

       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.

      2.3.2 Nutritional Additives

      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.

      Nutritional additives include fortification of salt with iodine, enrichment of cereal and dairy products with vitamin A, B, and D, enrichment of fruit beverages with vitamin C, essential fatty acid, mineral, and fiber [11].

      2.3.3 Flavoring Agent

      Flavoring agent includes flavorings and flavor enhancers. Flavorings added in the food produce flavor in the food, while flavor enhancer intensifies the existing flavor. Food flavoring may be of three types.

       a. Natural flavoring: These are single or mixed substances obtained from vegetable and animal source. This type of flavoring includes spice oleoresin and essential oils from citrus oils.

       b. Nature identical flavoring: These are the chemical substances but the identical substances are present in nature.

       c. Artificial flavoring: These types of compounds are completely synthetic and they are not identified in natural products.

      Natural flavor includes spices, herbs, essence, and essential oil. The synthetic flavor includes esters, aldehydes, ketones, alcohols, and ethers. Monosodium glutamate is an example of widely used flavor enhancer [12, 13].

      2.3.4 Coloring Agent

      Coloring agents are added into the food to make it attractive and to influence the flavor. The other reasons for the addition of food color are as follows:

       a. Color may be lost during processing and storage, so to compensate it, food color is used.

       b. Food material containing natural color may show variation of color food color is added to correct that variation.

       c. Food color is added to improve the color imparted by the natural color.

       d. Food color is used for the food items having no color.

      As per FDA regulation, the colors added may be with or without certification. The certified colors are man-made color. They are more effective than the natural color. They do not introduce any off flavor in the food. The natural colors are exempted from certification but they are more expensive and can produce off flavor. Color additives used may be of three types.

       a. Pure pigment or straight color.

       b. Colors obtained by mixing the straight colors with other substances.

       c. Mixtures produced by mixing two or more pure colors.

      Natural food color includes annatto, betanin, saffron, lycopene, and anthocyanin. The certified food color includes Erythrosine, Tartrazine, Sunset Yellow, and Brillant Blue [14]. Natural color additives have some health benefits. For example, curcumin has antimicrobial and antioxidant activity. Riboflavin has antioxidant activity.

The natural and synthetic food colors permitted by FSSAI (Food Safety and Standards Authority of India), 2011, are mentioned in Tables 2.2 and 2.3.

Table 2.2 List of natural food colors permitted by FSSAI.

Name of the color	Type	Color
Carotene and carotenoid	Natural	Orange
Chlorophyl		Green
Riboflavin		Yellow-orange
Caramel		Dark brown
Annatto		Orange-red
Saffron		Yellow or orange
Curcumin or turmeric		Yellow

Table 2.3 List of synthetic food colors permitted by FSSAI.

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Name of the color	Color	Type of the color	ADI (mg/kg of body weight)
Ponceau 4R	Red	Synthetic	4.0
Carmoisine	Red		4.0
Erythrosine	Red		0.1
Tartrazine	Yellow		7.5
Sunset Yellow FCF	Yellow		2.5
Indigo Carmine