| Summary: | 碩士 === 東海大學 === 食品科學系 === 91 === ABSTRACT
Six strains of lactic acid bacteria（Lactobacillus bulgaricus CCRC 14009, Streptococcus thermophilus CCRC 12257, Lactobacillus acidophilus CCRC 10695, Lactobacillus casei CCRC 10697, Bifidobacterium bifidum CCRC 11844, and Bifidobacterium longum CCRC 11847）were selected as the starter organisms in this research to study the effect of using single and mixed strains of lacic acid starters on the manufacture of blackbean milk yogurt.
Result showed that blackbean milk yogurt products made from mixed strains had higher viable count, higher titratable acidity, shorter fermentation time (pH=4.6) and higher viscosity as campared with those made from single strains. In addition, mixed strains showed higher sugar utilization (sucrose, stachyose and fructose) and higher production of lactate and vitamin B complex (B1＆B2) than single strains. Therefore, using mixed-strain starters could produce blackbean milk yogurt with better nutritious value and physical property.
After stored at 4℃ for 28 days, blackbean milk yogurt made from mixed strains of B. longum＋S. thermophilus＋L. bulgaricus had better microbiological and physical properties than those made from other 4 mixed-strain starters. This yogurt product showed the highest viable count (8.78 Log CFU/ml), survival rate (75.9%), titratable acidity (0.495%) and viscosity; and the lowest syneresis rate.
Sensory evaluation of the yogurt product made from mixed strains of B. longum＋S. thermophilus＋L. bulgaricus indicated that adding 10% (w/v) sucrose or 6% (w/v) sucrose＋2% (w/v) lactose＋2% (w/v) glucose could improve the sensory property and raise the acceptability of this product. For economical concern, the former would be recommended.
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