UHT热处理对牛奶中风味物质的影响

结合固相微萃取(SPME)及气相色谱-质谱(GC-MS)研究UHT热处理后牛奶的风味变化,并与原料牛乳风味特征进行对比。结果表明:新鲜原料乳中可以检测到50种挥发性风味物质,其中酸类最多,其他还包括醛,醇,酮,酚,酯等。牛乳经过137℃,4 s加热杀菌后,挥发性风味物质有75种,除上述风味化合物外,酯类和酮类数量明显增加,其中甲基酮,3-羟基-2-呋喃酮,δ-癸内酯,γ-十二内酯是UHT乳中重要挥发性风味物质,对形成UHT乳特有风味起重要作用。

Effect of UHT Treatment on Volatile Compounds in Milk

The volatile profile of raw milk and UHT milk was studied by the method of solid-phase micro-extraction and gas chromatography–mass spectrometry(SPME–GC–MS) to determinate the characteristic volatile compounds of UHT milk and to know the change in the volatile profile of milk before and after UHT treatment.A total of 50 compounds were detected in raw milk,in which carboxylic acids were the most abundant volatile compounds.Other volatile compounds include acids,aldehyde,ketones,esters,alcohols and phenol.About 75 volatile compounds were identified and quantified after the heat treatment with 137 ℃,4s.Content of volatile compounds was significantly modified(P < 0.05) and the relative total amounts of esters and ketones increased after UHT heat treatment.The most characteristic compounds of UHT milk aroma were some methyl ketones(2-butanone,2-pentanone and 2-heptanone),3-Hydroxy-2-pyranone,δ-Decalactone and γ-Dodecalactone.