Colouring properties and stability of black carrot anthocyanins in yoghurt

Among the natural pigments anthocyanins have potential to be applied as natural colourants besides exhibiting wide range of bioactivity. Colouring potential and storage stability of black carrot concentrate (BCC) containing anthocyanins in yoghurt was determined in present investigation. The instrumental colour (CIELAB) values were altered by the addition of BCC in yoghurt in which the L* and b* values decreased, while a* value increased with increasing levels of BCC. Maximum sensory scores were observed for yoghurt with 1.5% BCC, as it was similar to strawberry in colour and appearance. Enhancement in the total anthocyanin, total phenolics and DPPH antioxidant activity was observed with increasing levels of BCC in yoghurt. L* value remained same during storage in both yoghurts, but a* value increased slightly. Similar trend was also noticed in BCC yoghurt for anthocyanins and antioxidant activity. The total phenolic content got enhanced in control, but decreased significantly in BCC yoghurt. Sensory evaluation revealed that scores decreased during storage but the product was acceptable up to 15 days. Our study further confirmed that higher stability and better colouring properties of black carrot concentrate in fermented milk system was due to higher degree of acylation.