ABSTRACT

The effect of concentration of the starter culture on the quality parameters of malted and unmalted soy-yoghurt were studied .Significant changes occurred in the seven parameters pH, redox potential, total solid, soluble solid, total titrable acidity, aerobic and anaerobic count. Values of concentration one for malted unmalted were quite similar .For malted were 4.44 for pH, 144.86 for redox potential, 11.20 for total solid, 3.90 for soluble solid, 0.435 for total titrable acidity, 6514.28 for aerobic count and 3685.71 for anaerobic count. While for concentration eight the values were 4.70 for pH, 168.57 for redox potential , 16,87 for total solid ,6.74 for soluble solid ,0.170 for TTA, 7957.14 for aerobic count and 5914.29 for anaerobic count. The concentration had the best quality parameter after seven days. The concentration one starter culture was used to produce soy- yoghurt used to study the effect of storage period on quality parameters. There was a significant decrease (p<O.OS) in pH (5.25-4.25), the redox potential increased significantly until seven days (138.38-151.75). Total solid significantly decreased from 18.25 to 7.20 on day seven. TTA increased significantly from 0.156-0.491. Aerobic count increased from 4037.50 - 9450.00 and anaerobic count also increased from 2837.50 on day one to 6637.00 on the seventh day. The best preservation techniques for soy yoghurt were studied. Refrigeration techniques had the best preservative effect judging from their quality parameters also. The sensory attributes showed that the unmalted soy- yoghurt favourably with the commercial fan yoghurt.