Bio-utilization of Soybean Meal for the Production of Food Bio-Colours through Solid State Fermentation

Natural pigments are an important alternative to potentially harmful synthetic dyes used as colourant in food. The feasibility of soybean meal as a substrate for production of food bio-colour by Monascus purpureus (MTCC 410) in solid state fermentation was investigated to optimize the fermentation conditions. The results showed that the highest yield of red, orange, yellow and total bio-colour were 29.36 Units/g dms at 500 nm, 23.06 Units/g dms at 475 nm, 9.80 OD Units/g dms at 375 nm and 62.22 OD Units/g dms respectively achieved with soybean meal at optimized process parameters that include 65% (w/v) initial moisture content, 0.3–0.4 mm particle size, temperature 30°C, pH 6, inoculation with 3% spore suspension of 6 days old culture and an incubation period of 9 days. The yield of bio-colours indicated that soybean meal has good potentiality to be used as a substrate for the production of food bio-colours through solid state fermentation.