GC-O-MS分析热处理前后西瓜汁挥发性风味成分

利用GC-O-MS分析热处理前后西瓜汁的挥发性有机物风味成分。结果表明,GC-O-MS鉴定出鲜榨西瓜汁44种气味化合物,热处理西瓜汁50种气味化合物。结合嗅闻、气味稀释因子和香气活性值确定鲜榨西瓜汁中的关键气味化合物是壬醛(清香、青草味)、反-2-壬烯醛(清香、黄瓜味)、反,顺-2,6-壬二烯醛(清香、黄瓜味)、反,顺-3,6-壬二烯醇(清香、黄瓜味)、反,顺-2,6-壬二烯醇(清香、黄瓜味)和香叶基丙酮(花香、甜味)；热处理西瓜汁中关键气味化合物为反-2-庚烯醛(脂味、苦味)、1-癸醛(脂味、肥皂味)、6-甲基-5-庚烯-2-酮(蘑菇味、霉味)、苯乙酮(苦杏仁味)、二乙基二硫醚(大蒜味)和顺-6-壬烯醛(臭味、刺激味)。顺-6-壬烯醛特征气味原为清香、黄瓜味,而热处理西瓜汁中顺-6-壬烯醛的含量增大,超过感官评价员鼻子的耐受值,呈现臭味、刺激味。热处理产生了异味成分,气味化合物的变化导致了西瓜汁加热后的蒸煮味。

Effect of Heat Treatment on Volatile Flavor Components of Watermelon Juice by GC-O-MS Analysis

Using GC-O-MS to compare and analyze the change of volatile flavor components in watermelon juice before and after heat treatment. The results showed that 44 and 50 odor compounds were identified by GC-O-MS in fresh and heated watermelon juice, respectively. The key odor compounds in fresh watermelon juice were nonanal (freshness and herbaceous flavor), (E)-2-nonenal (freshness and cucumber flavor), (E, Z)-2,6-nonadienal (freshness and cucumber flavor), (E, Z)-3,6-nonadienol (freshness and cucumber flavor), (E, Z)-2,6-nonadienol (freshness and cucumber flavor) and geranyl acetone (flower fragrance and sweet taste) identified by combination of sniffing, odor dilution factor and odor activity value. However, the key odor compounds in heated watermelon juice were (E)-2-heptenal (fat flavor and bitterness), decanal (fat flavor and soap flavor), 6-methyl-5-hepten-2-one (mushroom and musty flavor), acetophenone (bitter almonds flavor), diethyl disulfide (garlic flavor) and (Z)-6-nonenal (pungent odor). Among them, the characteristic odor of (Z)-6-nonenal was fresh and cucumber flavor initially. Due to the concentration of (Z)-6-nonenal in heated watermelon juice exceeding the tolerance of the sensory assessor''s nose, it showed an irritating smell. The heat treatment produced odorous components, and the change in odor compounds led to the cooking taste of the watermelon juice after heating.