酶解辅助预糊化技术工艺优化及风味物质差异分析

利用响应面试验设计优化糙米的酶解辅助预糊化工艺，以蒸煮时间为指标，得到最佳酶解辅助预糊化工艺条件，用气相色谱–离子迁移谱法（GC-IMS）测定白米、糙米和酶解辅助预糊化糙米及其蒸煮前后的挥发性物质。结果表明，最优工艺条件为酶解时间为4 h、酶的添加量为0.1%、预糊化时间为10 min，酶解温度为39 ℃。在酶解辅助预糊化糙米中检测到56种挥发性物质，其中醛类19种，酮类8种，酯类6种，醇类12种及其它类11种；而蒸煮后的酶解辅助预糊化糙米中检测到44种挥发性物质，其中醛类18种，酮类8种，酯类3种，醇类11种及其它类4种，且2-辛烯醛、苯乙醛、苯乙酮、乙偶姻、γ-丁内酯、戊酸、己酸、丁酸和己二烯二硫化等挥发性物质在蒸煮之后消失。糙米酶解辅助预糊化前、后挥发性风味成分改变最大的为醛类、酮类和醇类；而酶解辅助预糊化糙米蒸煮前、后挥发性风味成分改变最大的为酯类和其它类中的酸类。

Process Optimization of Enzyme-assisted Pregelatinization Technology and Analysis of Flavor Substance Difference

The response surface experiment was used to design and optimize the enzyme-assisted pregelatinization process of brown rice. The optimum conditions of enzyme-assisted pregelatinization process were obtained through the cooking time: The enzymatic hydrolysis time was 4 h, the amount of enzyme added was 0.1%, the pregelatinization time was 10 min and the enzymatic hydrolysis temperature was 39 ℃. Gas chromatography-ion migration spectrometry(GC-IMS) was used to determine the volatile substances of white rice, brown rice and enzyme-assisted pregelatinized brown rice before and after cooking. 56 kinds of volatile substances were detected in enzymolysis assisted pregelatinized brown rice, including 19 kinds of aldehydes, 8 kinds of ketones, 6 kinds of esters, 12 kinds of alcohols and 11 kinds of other compounds. Forty-four kinds of volatile substances were detected in the pregelatinized brown rice assisted by enzymatic hydrolysis after cooking,including 18 kinds of aldehydes, 8 kinds of ketones, 3 kinds of esters, 11 kinds of alcohols and 4 kinds of other compounds,and 2-octenal, phenylacetaldehyde, acetophenone, acetoin, gamma-butyralide, pentanoic acid, hexanoic acid, butyric acid and hexadiene disulfide and other volatile substances disappeared after cooking.Aldehydes, ketones and alcohols showed the largest changes in the volatile flavor components of brown rice before and after the enzymatic hydrolysis assisted pregelatinization. The acids in esters and other groups showed the greatest changes in the volatile flavor components of brown rice before and after cooking assisted by enzymatic hydrolysis.