摘要
针对牦牛乳脂肪含量高、营养丰富等特点,本试验研究了适用于发酵牦牛乳的菌种和工艺。以发酵牦牛乳的感官、酸度以及活菌数为指标,从10株乳酸菌中筛选适合牦牛乳发酵的3株菌;在单因素试验基础上,利用响应面优化发酵牦牛乳配方及工艺;测定发酵牦牛乳的理化卫生指标,评估产品质量。结果表明:适用于发酵牦牛乳的3株菌为罗伊氏乳杆菌、约氏乳杆菌和发酵乳杆菌,可与保加利亚乳杆菌及嗜热链球菌按1:1:1:1:1比例复配制成发酵剂;发酵牦牛乳最佳工艺条件为:牦牛奶与荷斯坦牛奶按2:1配比,糖添加量为9%,菌种添加量为4%,30℃发酵30h。回归系数显著性表明,各因素对发酵乳感官评分的影响顺序为:菌种添加量>发酵温度>糖添加量>发酵时间。理化和微生物指标结果显示,发酵牦牛乳的酸度、脂肪、蛋白质、酵母菌和霉菌数、大肠菌群数均符合标准,风味成分双乙酰含量为1.02μg/mL。
Aiming at the characteristics of high fat content and rich nutrition in yak milk,the strain and technology suitable for fermenting yak milk are studied.Using the sensory,acidity and viable bacterial counts of fermented yak milk as indicators,select 3 strains suitable for yak milk fermentation from 10 strains of lactic acid bacteria;on the basis of single-factor experiment,use response surface to optimize the fermentation yak milk formula and process;determine fermentation physical and chemical health indicators of yak milk to evaluate product quality.The results show that the three strains suitable for fermenting yak milk are Lactobacillus reuteri,Lactobacillus yoelii and Lactobacillus fermentum,which are formulated with Lactobacillus bulgaricus and Streptococcus thermophilus in the ratio of 1:1:1:1:1.The best process conditions for fermenting yak milk are:2:1 ratio of yak milk to Holstein milk,sugar addition amount 9%,strain addition amount 4%,30℃fermentation for 30h.The significance of the regression coefficient indicates that the order of the influence of various factors on the sensory score of fermented milk is:the amount of bacteria added>fermentation temperature>the amount of sugar added>fermentation time.The results of physical and chemical and microbiological indicators showed that the acidity,fat,protein,yeast and mold count,and coliform count of the fermented yak milk all met the standard,and the diacetyl content of the fl avor component was 1.02μg/mL.
作者
杨婧
郑娴余
魏光强
赵存朝
毛兴菊
黄艾祥
YANG Jing;ZHENG Xian-yu;WEI Guang-qiang;ZHAO Cun-chao;MAO Xing-ju;HUANG Ai-xiang(College of Food Science and Technology,Yunnan Agricultural University,Kunming 650201)
出处
《中国奶牛》
2020年第9期44-49,共6页
China Dairy Cattle
关键词
发酵牦牛乳
菌种筛选
加工工艺
响应面
理化卫生指标
Fermented yak milk
Strain selection
Processing technology
Response surface
Physical and chemical hygiene indicators
