| Summary: | 碩士 === 國立嘉義大學 === 食品科學系碩士班 === 93 === Abstract
This study investigated five strains of lactic acid bacteria（Bifidobacterium longum CCRC 14605, Lactobacillus casei CCRC 10697, Lactobacillus delbrueckii ssp. bulgaricus CCRC 14075, Streptococcus thermophilus CCRC 12257 and Lactococcus lactis ssp. lactis CCRC 12315）were selected as the starter organisms fermented on hen egg yolk with two level（25% and 10%）sugar content. In order to research on the optimum conditions for the maximum of organisms count. We used response surface method of central composite design for three variable factors（sugar content、yolk content and fermented time）.The maximum of organisms count yield which three optimum conditions. The culture of maximum of organisms count that higher total solid on low level sugar content and the same situation of higher total solid on high level sugar content. We set yolk（50%）and glucose（3%）,then added sugar of three level.（7%、15% and 22%） Single strain of lactic acid starter incubated on the three culture. Sugar utilization and protein property change that using various lactic acid bacteria on the yolk culture. It showed that the lowest glucose content during fermented 12 hour and the sucrose content during fermented 36 hour on three yolk of sugar content. Soluble protein content increase initially then it decreasing convert into increasing. The break point was during fermented 24 hour. Peptide concentration of low and medium level increased little on fermented stage. But peptide concentration decreased on high sugar medium. The amino acid-nitrogen content increased of fermented stage. SDS-PAGE profile, it was significantly different. The low sugar level have two new bands （170-116kDa and 30-20.1kDa）of Lactobacillus casei CCRC 10697, Lactobacillus delbrueckii ssp. bulgaricus CCRC 14075, Streptococcus thermophilus CCRC 12257 on fermented 48 hour. But low sugar level only have a new band （170-116kDa）of Lactococcus lactis ssp. lactis CCRC 12315 on fermented 48 hour. Bifidobacterium longum CCRC 14605’ SDS-PAGE profile, it was not significantly different on fermented stage. It means various lactic acid bacteria’ protein enzyme can lyses special protein into peptide of low molecular weight.
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