热处理对乳熟期玉米汁挥发性风味成分的影响

Effect of Heat Processing on the Volatile Flavor Components of Milk-Stage Corn Juice

为明确热处理对玉米汁加工过程中风味变化的影响,本文选用乳熟期的甜玉米及糯玉米进行制汁,对生鲜玉米汁以及烫漂、常压沸水、高压蒸汽热处理后的样品采用SPME-GC-MS,进行挥发性成分测定。结果表明:两种生鲜玉米汁的挥发性成分均以直链醛醇类物质为主,经烫漂处理后制汁,醛醇类物质分别由14种和15种减少为5种和0种,峰面积减少为生鲜玉米汁的48.7%与0.0%。对烫漂后加工得到的玉米汁样品再进行常压沸水处理和高压蒸汽处理。常压沸水处理的样品中挥发性成分的数量及含量较未加热的样品增加不明显。高压蒸汽热处理的两种样品中检测到的成分数量分别增加为加热前的2.6和2.8倍,总峰面积则分别增加为3.4与12.7倍。另外,虽然常压沸水处理的两个玉米汁中均检测到了玉米的特征香气成分二甲基硫醚,但高压蒸汽热处理的样品含量为前者的30倍与300倍。热处理引起的两种玉米汁挥发性成分的变化体现了二者对热处理的敏感程度不同,实际加工中应针对不同原料选择适宜的加热方法。本研究为玉米汁生产工艺的优化、风味品质的提高提供借鉴作用。

The objective of this study was to evaluate the effect of heat treatment on the flavor substance of milk-stage sweet corn or waxy corn juice. The volatile components of the two samples treated by blanching, boiled water or autoclaving were analyzed by SPME-GC-MS. Linear aldehydes and alcohols were main components in the fresh corn juices. The total number of volatile compound was decreased obviously in the corn juices made by blanching-treated knernels. The type of aldehydes and alcohols was loss from 14 to 5, 10 to 0, and peak areas was significantly decreased, account for 48.7% and 0.0% of fresh corn, respectively. After heating by boiled water, no significant change was observed for the number and content of volatile components. Autoclaving treatment was found to increase the number of volatile components in the juices with 2.6 and 2.8 folds, while total peak areas increased 3.4 and 12.7 folds. Although one of the most important flavor compounds attribute to corn flavor, dimethyl sulfide was detected, the content of dimethyl sulfide was up to thirties or three hundred times. In summery, the flavor components of sweet and waxy corn juice showed showed different sensitivity to heat treatment, suggesting different parameters should be applied. This study would make a reference to corn juice processing optimization and quality enhancement.