摘要 : Cow milk, standardized to 3% fat and to 16% TS with dried skim milk (control) or condensed Cottage cheese whey, was used in the preparation of plain set yoghurt and frozen yoghurt. The process involved addition of 5% sugar, homoge... 展开 Cow milk, standardized to 3% fat and to 16% TS with dried skim milk (control) or condensed Cottage cheese whey, was used in the preparation of plain set yoghurt and frozen yoghurt. The process involved addition of 5% sugar, homogenization and heat treatment prior to inoculation of 1% each of Streptococcus salivarius subsp. thermophilus NDRI YH-S and Lactobacillus delbrueckii subsp. bulgaricus NDRI YH-L and incubation at 30degC to pH 4.6; a mixture of cream, sugar, sodium alginate and glycerol monostearate was blended with the set yoghurt prior to ageing, freezing and storage at -20degC. Mean composition of the frozen yoghurt was 10% fat, 13% SNF, 15% sugar, 0.25% sodium alginate, 0.25% glycerol monostearate and 61.5% water. There appeared to be no biochemical activity of the starter bacteria during storage, but tyrosine values increased during preparation and the 1st 15 days of storage. Starter bacteria count decreased during preparation and storage of frozen yoghurt, but sufficient viable cells remained at the end of the 90-day storage period, and flavour, body/texture, colour/package and melting quality scores of frozen yoghurt made with condensed Cottage cheese whey were comparable with those of control yoghurt. 收起