杀菌方法对牛乳中特征香气物质的影响

Effect of Sterilization Methods on Characteristic Aroma Compounds in Milk

超高温瞬时杀菌法(UHT)、巴氏杀菌法和浸入式杀菌技术(INF)等是应用较为广泛的牛乳杀菌方法,本研究利用溶剂辅助风味蒸发法(SAFE)对生牛乳和3类杀菌乳中挥发性风味组分差别进行研究,结果表明:从4种牛乳中共检出挥发性香气物质48种,包括脂肪酸类11种、酮类5种、醛类6种、含硫化合物2种、酯类6种、醇类5种、芳香及杂环类化合物13种。在此基础上结合阈值进一步确定了上述风味组分的香气活性值(OAV)。4种牛乳样品中共有23种OAV值大于1的关键风味化合物,其中十六酸甲酯、2-壬酮和己醛等对牛乳整体风味的贡献度较大。基于偏最小二乘回归(PLS)对4种牛乳中关键风味组分和牛乳感官特征之间的相关性进行分析,结果表明:INF乳和巴氏杀菌乳的感官特征更为相似,具有较强奶香味与甜味,其对应的化合物为2-壬酮、2(5H)-呋喃酮和乙酸丁酯。UHT乳的感官特征为具有蒸煮味、浓厚感较强。该感官特征与二甲基砜、二甲基硫、2-乙基-1-己醇和2-十三酮等组分相关性较大。此外,生牛乳风味组分相对较少。

Ultra-high temperature(UHT)instantaneous sterilization,pasteurization and infusion(INF)technology are com monly used in milk sterilization.In this study,solvent assisted flavor evaporation(SAFE)method was used to study the difference of volatile flavor components in raw milk and three kinds of sterilized milk.The results showed that there were48 volatile compounds were detected in four kinds of milk,including 11 fatty acids,5 ketones,6 aldehydes,2 sulfur compounds,6 esters,5 alcohols,13 aromatic and heterocyclic compounds.On this basis,the odor activity value(OAV)of the above flavor components was further determined by combining with the threshold.There were 23 key flavor compounds with OAV greater than 1 in the four milk samples,among which hexadecanoic acid,methyl ester,2-nonanone and hexanal contributed more to the overall flavor of milk.Partial least squares(PLS)regression was used to analyze the correlation between the key flavor components and the sensory characteristics of four kinds of milk.The results showed that the sensory characteristics of INF milk and pasteurized milk were more similar,with strong milk flavor and sweet flavor,and the corresponding compounds were 2-nonanone,2(5H)-furanone and butyl acetate.The sensory characteristics of UHT milk were cooking flavor and strong sense,which were highly correlated with dimethyl sulfone,dimethyl sulfur,2-ethyl-1-hexanol and 2-tridecanone.In addition,the flavor components of raw milk were relatively less.