Effect of Flavourings on Quality and Consumer Acceptability of Soy-Yoghurt

Abstract

Inspite of the characteristic objectionable painty odour, soybean is an attractive value added food grain because of its higher nutritive value. The effect of different flavourings on the quality and acceptability of soy-yoghurt were studied. The flavours were added at 5% (W/V). Soy-yoghurt flavoured with synthesized vanilla, banana, strawberry, pineapple and natural ginger flavours, control without flavouring and commercial yoghurt were all compared for proximate, pH, percentage lactic acid, specific gravity, soluble solids, percentage syneresis and microbial count. Sensory evaluation was also conducted in order to determine the acceptability of the samples. The protein content of plain soy-yoghurt was 3.33; commercial yoghurt was 3.74 while that of flavoured soy-yoghurt ranged from 3.47 and 3.69. The pH and %lactic acid contents ranged from 4.2-5.0 and 0.70-1.31 respectively on the second day of storage while the values were 4.0-4.7 and 1.30-1.71 on the eighth day of storage at refrigeration temperature. The lactic acid values increased with decreasing pH values. The %syneresis ranged from 41.30-54.09 and 42.65-56.21 for flavoured soy-yoghurt while it was 37.75 and 38.13 for plain soy-yoghurt on the second and eighth day of storage. The values increased with increasing storage days. Microbiological examination revealed that the samples were within the minimum acceptable standards. The sensory evaluation also showed that there was no significant difference (P≤0.05) for taste, consistency and overall acceptability among all the samples. However, banana soy-yoghurt was the most preferred by the sensory panelists with respect to all quality attributes except consistency while ginger soy-yoghurt was the least preferred with respect to all quality attributes except taste.