FERMENTABILITY AND RHEOLOGICAL PROPERTIES OF LACTOPEROXIDASE ACTIVATED BUFFALO MILK YOGHURT

Abstract

Present study was planned to produce and evaluate the coagulum from buffalo milk preserved with the activation of its lactoperoxidase system (LPO-system). A total of 10 trials were conducted and in each trial milk base was equally divided into three parts, two of which were treated with 20 mg/L (A) and 30 mg/L (B) solution of Sodium thiocyanate + Hydrogen peroxide and third part was kept as control (C). All the samples were analyzed for fermentability trend, pH, acidity, viscosity, specific gravity, syneresis and organoleptic properties. The decreasing trend in pH during fermentation period was comparatively slow in LPO-system activated milk A and B (4h and 5h) as compared to control yoghurt (3h). The titratable acidity (% lactic acid) of A, B and C yoghurt was 0.86±0.022, 0.85±0.025 and 0.89±0.024, respectively. The viscosity and specific gravity of control yoghurt was significantly (P<0.05) higher than A and B yoghurt. Whey syneresis was recorded as 2.08±0.24 ml 2h-1 in control yoghurt, whereas, 2.32±0.26 and 2.5±0.27 ml 2h-1 in A and B yoghurts. No significant differences (P>0.05) were observed in the total solids, fat, ash, lactose and protein contents among the control, A and B yoghurt. Two week stored samples of control yoghurt received lower sensory score for appearance, flavor, body/texture and overall acceptability as compared to fresh control yoghurt. Simultaneously, LPO-system treated A and B yoghurt received high score during storage period than the control yoghurt.