摘要
以乳酸菌单一菌种和多菌组合分别发酵苹果汁,采用紫外-可见分光光度计测定发酵过程中苹果汁光密度(optical density,OD)的变化,采用顶空固相微萃取和气相色谱-质谱联用技术检测9组发酵苹果汁的香气成分,结合不同香气物质的阈值与香气值分析特征香气成分,并对各组苹果汁进行感官评价。结果表明:在发酵过程中苹果汁的OD值呈对数上升趋势。各组苹果汁中共鉴定出48种香气成分,主要包含醇类、酯类、醛类、酮类和酚类,其中酯类是各发酵组中种类最多且含量最大的香气类别,其次是醇类。9组苹果汁的主要香气成分和香气值较大并有突出贡献的特征香气成分均为丁酸乙酯、2-甲基丁酸乙酯、2-甲基丁基乙酸酯和乙酸己酯等。多菌发酵和单菌发酵苹果汁的香气成分含量及香气值差异显著(P<0.05),说明多菌发酵中醇类、酯类和其他类香气物质的总含量明显高于单菌发酵,且赋予苹果汁更强烈的果香、青香和花香。多菌发酵组的总体感官评分高于单菌发酵组,当副干酪乳杆菌20241、动物双歧杆菌6165、嗜热链球菌6063、嗜酸乳杆菌6005活菌数比为1∶1∶1∶1时,感官评分最优。研究结果为今后乳酸菌在发酵果蔬汁方面的研究和应用提供理论依据。
In this study,changes in optical density(OD)during the fermentation of apple juice with pure and mixed culturesof lactic acid bacteria were monitored by a UV-Vis spectrophotometer.The aroma components of nine fermented applejuices were identified by head-space solid phase micro-extraction(HS-SPME)combined with gas chromatography-massspectrometry(GC-MS),and the characteristic aroma components were evaluated by odor activity value(OAV)and odorthreshold value(OTV).Sensory evaluation was also carried out on the samples.The results showed that the OD value ofapple juice increased logarithmically with time.Forty eight aroma components were identified from nine fermented applejuices,mainly including alcohols,esters,aldehydes,ketones and phenols.Esters were the most abundant components withthe highest species diversity,followed by alcohols.In addition,according to their aroma values,butyric acid ethyl ester,ethyl-2-methylbutyrate,2-methylbutyl acetate and hexyl acetate were the main aroma components in all the fermentedsamples.The contents of aroma components and aroma values from single and mixed culture fermentation of apple juicewere significantly different(P<0.05).It was shown that the total contents of alcohols,esters and other aroma componentswith mixed culture fermentation were significantly higher than those of single culture fermentation and apple juice fermentedwith single cultures had a stronger fruity,green and flowery aroma.The overall sensory score of apple juice fermentedwith mixed cultures was higher than that of single culture fermentation.A mixed culture of Lactobacillus paracasei20241,Bifidobacterium animalis6165,Streptococcus thermophilus6063and Lactobacillus acidophilus6005at a ratio of1:1:1:1was the optimal combination in sensory acceptance.These results can provide a theoretical basis for the research andapplication of lactic acid bacteria in fermented fruit and vegetable juice.
作者
李维妮
郭春锋
张宇翔
魏建平
岳田利
LI Weini;GUO Chunfeng;ZHANG Yuxiang;WEI Jianping;YUE Tianli(College of Food Science and Engineering, Northwest A&F University, Yangling 712100, China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2017年第4期146-154,共9页
Food Science
基金
国家自然科学基金面上项目(31371814)
关键词
苹果汁
乳酸菌
多菌发酵
香气成分
顶空固相微萃取法
气相色谱-质谱法
apple juice
lactic acid bacteria
mixed-strain fermentation
aroma components
head-space solid phase microextraction
