Chemical additives for preserving the betalain pigment and antioxidant activity of red beetroot

Beetroot is one of the most important industrial crops from Caryophyllales order cultivated for its natural colourant, betalains and exceptionally high antioxidant activity. Like other natural pigments, betalains are also associated with reduced stability problem. The effectiveness of various additives for betalain and antioxidant stability was examined in this study. Beetroot (Beta vulgaris L.) cv. Crimson Globe was harvested at the physiological maturity stage used for this study. Each additive was added as per the prescribed limits given by Food Safety and Standards Authority of India (FSSAI) for food uses. Data on total betalain content, total colour change and total antioxidant activity in terms of CUPRAC were recorded after every 24-h interval till significant degradation was recorded in all incubations. Additives, namely 1% ascorbic acid, 10% glucose/ fructose, sucrose [45%, EDTA 40 ppm and sodium benzoate 350 ppm, were found best for imparting maximum betalain stability. A lower concentration of salt (\3.0%) was the best to impart stability of betalain pigments and antioxidant activity in beetroot extract. Almost in all incubations, betalains and colour degradation followed a similar trend; however, antioxidant activity was not the exact replica of betalain content. The stability of the pigment was confirmed by enhanced halflife and lower rate constant under first-order degradation kinetics