一种具高抗氧化活性羊乳发酵乳最佳工艺优化

Optimization of Preparation Conditions for Fermented Goat Yogurt with Antioxidant Activity

试验利用一种实验室优化的植物乳杆菌(LP_(GY-L086))与嗜热链球菌(Yo-Mix 300 LYo 50 Dc)复配菌株发酵制备具高抗氧化活性的羊乳发酵乳。试验研究了菌种复配比、接种量、发酵温度和发酵时间对羊乳发酵乳品质的影响,通过综合指标·OH清除能力、DPPH清除率及螯合Fe^(2+)能力评价产品的抗氧化活性,并探讨了贮藏条件对产品质量特性的影响。结果表明:(1)在杆菌与球菌以1∶1复配、接种量4%、42℃发酵条件发酵5.5 h,羊乳发酵乳产品品质最优,其·OH清除率、DPPH清除率及螯合Fe^(2+)能力分别为89.85%±1.21%,85.30%±2.60%和20.76%±2.46%,较未发酵羊乳分别提高了55.85%,104.31%和134.05%;(2)产品于不同温度存放,4℃时其各项指标均保持良好状态,30 d存放后活菌数仍达国标(>10^(6 )CFU/m L)要求,且·OH清除率仍在75%以上;25℃时发酵乳的指标波动显著,不被接受。

A kind ofLactobacillus plantarum （LP GY-L086） of laboratory optimized and Streptococcus thermophiles （Yo-Mix 300 LYo 50 De） was used to produce goat yogurt with antioxidant activity. Study the Lactobacillus plantarum to Streptococcus thermophiles ratio, inoculation size, fermentation temperature and fermentation time, which impacted on the quality of goat yogurt. By measuring the .OH radical scavenging ability, antioxidant activity of goat yogurt was evaluated, and the influence of storage temperature on the past-acidification was explored. The results showed that： （1） The optimum conditions for skimmed goat milk fermentation included bacteria mix ratio 1 ： 1, inoculum 4%, fermentation temperature 42 ℃ and fermentation time 5.5 h, its clearance abilities of .OH and DPPH and chelating ability of Fe2＋ were 89.85% ±1.21%, 85.30%±2.60% and 20.76%±2.46%, respectively, than unfermented defatted goat milk respectively increased by 55.85%, 104.31% and 134.05%; （2） Products in different storage temperature, under 4℃, the indicators were in good condition, and the number of living bacterium after 30 d storage was still up to national standard （〉 106 CFU/mL）, the .OH radical scavenging ability was still more than 75%; At 25 ℃ fermented milk index fluctuate significantly, it was not accepted.