【摘要】 从酸奶样品中分离纯化获得6株菌株,从自酿甜米酒样品中分离获得1株菌株后,对7株菌株进行了形态学观察,并对其中两株菌株进行分子鉴定,确定为乳酸菌和酵母菌。选取其中的乳酸菌RSJ-1菌株进行单菌发酵乳品的发酵实验,乳酸菌RSJ-1和酵母菌JMJ-1进行发酵乳品的混菌发酵实验,对发酵乳制品的凝乳状态、乳清析出、气味和pH值的变化情况进行评估。运用顶空固相微萃取技术和GC/MS检测技术,分析了乳酸菌单菌发酵乳制品和乳酸菌及酵母菌混菌发酵乳制品的挥发性风味物质。结果表明:单菌发酵乳和混菌发酵乳的挥发性风味成分主要为酸类、醇类、酯类、酮类、醛类和烃类物质,但各组分有较大差异。混菌发酵样品中增加了苯乙醇和3-甲基丁醇等风味物质,致使混菌发酵乳制品具有更好的风味。更多还原

【Abstract】 6 strains were isolated from yogurt and 1 strain isolated from sweet rice wine. The cell morphological characteristics of the 7 strains were identified, and 2 of them were determined as lactobacillus and yeast through 16 S rDNA and 26 S rDNA sequence analysis. The strain of RSJ-1 was used in the single fermentation test. The strains of RSJ-1 and JMJ-1 were used in the mixed fermentation test. The products of the two tests were evaluated by curd state, whey precipitation, odour and pH. It was found in the evaluation that the mixed fermentation milk product has better taste and full aroma. The combined technique of headspace solid phase microextraction(SPME) and gas chromatography-mass spectrometry(GC-MS) was used to analyze the flavoring substance of the two tests’ products. The results showed that six types of flavor compounds made contribution to the flavor of samples,including acids, alcohols,esters, ketones,aldehydes,and hydrocarbons. But there are differences in volatile flavoring substance between the single and the mixed fermentations. The mixed fermented milk product has the better taste due to the additional flavoring substance of Phenethyl alcohol and 3-methylbutanol.更多还原