Physicochemical, microbiological and sensory properties of carrot juice fortified set-style yoghurt

Abstract

An attempt has been made to develop carrot juice-based set-style yoghurt for enriched nutritional and therapeutic properties. Yoghurts were fortified with carrot juice at a ratio of 10%, 20%, 30%, 40% and 50% and were analyzed for physicochemical properties, bioactive compound (total phenolic content, total flavonoid content, vitamin C, antioxidants and β-carotene content) and organoleptic properties. Fortification of carrot juice significantly (p<0.01) increased the percentage of carbohydrates (35.47 to 42.92%), ash (0.57 to 0.87%), total solid (50.5 to 52.61%), solids non-fat (45.77 to 49.37%) and fibre (0.36 to 0.46%), and significantly (p<0.01) decreased the percentage of fat (4.73 to 3.24%). Similar increase in bioactive compounds also found with the fortification of carrot juice e.g., β-carotene (0.00 to 4.43 mg/100 g), antioxidant activity (18.29 to 48.42 %), TPC (0.00 to 15.44 mg/100 g), TFC (0.00 to 5.18 mg/100 g) and vitamin C (0.76 to 1.28 mg/100 g). No yeast, mould and coliform were observed in any yoghurt samples. The sensory analysis suggested that yoghurt fortified with 30% carrot juice was the best with the highest overall acceptability (8.4) along with the lowest syneresis (10.81%). The addition of carrot juice above this concentration started decreasing the scores of good qualities of the fortified yoghurts. Taking into account all findings, we concluded that carrot juice could be added up to 30% for large-scale production of fortified yoghurt.