Functional and technological attributes of probiotic yoghurt prepared with Dahi micro-flora during refrigerated storage

Abstract

In the present investigation functional, technological, and rheological attributes of probiotic yoghurt were studied during refrigerated storage (4 °C) for 28 days. The different preparations of probiotic yoghurts were made from dahi microflora which was documented as probiotics. Three strains of lactic acid bacteria (LAB) i.e. S. thermophilus (S02FT), L. bulgaricus (TLB06FT) and L. acidophilus (LA06FT) were selected for formulations of probiotic yoghurt. Three sets of probiotic yoghurt including Y1: S02FT and TLB06FT (1:1ratio), Y2: S02FT and TLB06FT (1:2ratio) and Y3: S02FT, TLB06FT and LA06FT (1:1:1 ratio) along with Y0 as a control (non-probiotic strains) were prepared and stored at 4 °C for 28 days. The results showed that technological attributes of Y3 preparation had better lactic acid production (75% at 0 day and 93% at 28 days) as compared to control. Moreover, Y3 preparation had lesser synersis (20% at 0 day and 35% at 28days) as compared to other treatments i.e. Y1, Y2, Y0 that had 24, 70 and 18% synersis at 0 day of storage respectively). However, viscosity of Y3 probiotic yoghurt indicated higher values (3001 cP at 0 days and 1310 cP at 28 days) among the rest of preparations. Functional attributes of Y3 showed the better results such as viability of probiotics (40×10^-6 CFU/ml at 0 day and 1.16×10^-6 CFU/ml at 28 days) and antibacterial activity (7.5 mm at 0 days 7 mm at 28 days) compared to other preparations. Conclusively, Y3 formulation attained the higher sensory attributes due to its better lactic acid production, viscosity and lesser synersis values during entire study duration in formulated yoghurt.

Keywords:
yoghurt; probiotics; antibacterial activity; cold storage; sensory evaluation; syneresis; viscosity