Stability Analysis of Food Bio-colour Extracts from Soybean Meal through Solid State Fermentation

An attractive and stable colour is important in the marketability of foods and beverages. However, replacing synthetic dyes with natural colorants poses a challenge due to the higher stability of synthetic colorants with respect to various conditions like light, temperature, pH and is therefore, a major concern in colouring foods. However, the lower stability of natural colourants against environmental factors could pose restriction to their utilization as food colorants in industry. Therefore, the stability of food bio-colour extracts from soybean meal fermented by Monascus purpureus (MTCC 410) in SSF was investigated under various conditions. The food bio-colour extracts were characterized for considerable stability and it was found that these extracts are stable in dark, at low temperatures (20°C, 40°C and 60°C) while the red, orange and yellow bio-colour extracts showed a good stability at pH of 6, 4 and 2, respectively. The stability of Monascus food bio-colours compares well with other natural colours, so that these food bio-colours will be a promising colour additive for food industry.