全因子试验设计优化产ACE抑制肽羊乳发酵工艺及其冷藏研究

以山羊乳为原料，产ACE抑制肽菌株保加利亚乳杆菌（Lactobacillus bulgaricus）LB6和嗜热链球菌（Streptococcus thermophilus）ST为发酵菌株，采用全因子试验设计对其发酵羊乳产ACE抑制肽的发酵工艺进行优化，并研究冷藏对其理化性质及质构的影响。结果表明，最优发酵工艺为菌株比例LB6∶ST=1∶1，发酵温度42 ℃，发酵时间3.5 h。在此优化条件下，发酵羊乳ACE抑制率、OD600 nm值和感官评分分别为78.37%、0.22、7.35分；随着冷藏时间的延长，发酵羊乳的pH值逐渐减小，酸度逐渐增大；ACE抑制率、活菌数、硬度、稠度、凝聚性和黏度指数呈现先上升后下降的趋势。

Fermentation technology optimization and refrigeration of goat milk containing ACE inhibitory peptide by full factorial experiment design

Using goat milk as raw material, and the strains (Lactobacillus bulgaricus LB6 and Streptococcus thermophilus ST) producing ACE inhibitory peptide as starting strain, the fermentation technology of goat milk containing ACE inhibitory peptides was optimized by the full factorial experiments, and the effect of refrigeration on its physicochemical properties and texture was also studied. The results showed that the optimal fermentation technology was strain ratio LB6∶ST=1∶1, fermentation temperature 42 ℃, time 3.5 h. Under the optimal conditions, the ACE inhibition rate, OD600 nm value and sensory score of fermented goat milk were 78.37%, 0.22 and 7.35, respectively. The pH value of fermented goat milk gradually decreased and the acidity gradually increased, meanwhile the ACE inhibition rate, viable counts, hardness, consistency, cohesiveness and viscosity index showed a trend of rising first and then decreasing with prolongation of refrigeration time.