中国农业科学 ›› 2018, Vol. 51 ›› Issue (21): 4131-4142.doi: 10.3864/j.issn.0578-1752.2018.21.011

• 食品科学与工程 • 上一篇    下一篇

微波处理对稻谷品质及脂肪酶活性的影响

袁建(),赵腾,丁超,邢常瑞,张斌,陈尚兵,何荣,鞠兴荣   

  1. 南京财经大学食品科学与工程学院/江苏省现代粮食流通与安全协同创新中心/江苏高校粮油质量安全控制及深加工重点实验室,南京 210046
  • 收稿日期:2018-03-23 接受日期:2018-05-16 出版日期:2018-11-01 发布日期:2018-11-01
  • 通讯作者: 袁建
  • 基金资助:
    现代粮仓绿色储粮科技示范工程(2016YFD0401603);江苏省高校优势学科建设工程资助项目、粮食采后“全程不落地”技术模式示范工程(2017YFD0401404)

Effects of Microwave Treatments on Rice Quality and Lipase Activity

Jian YUAN(),Teng ZHAO,Chao DING,ChangRui XING,Bin ZHANG,ShangBing CHEN,Rong HE,XingRong JU   

  1. College of Food Science and Engineering, Nanjing University of Finance and Economics/Collaborative Innovation Center for Modern Grain Circulation and Safety/Key Laboratory of Grains and Oils Quality Control and Processing, Nanjing 210046
  • Received:2018-03-23 Accepted:2018-05-16 Online:2018-11-01 Published:2018-11-01
  • Contact: Jian YUAN

摘要:

【目的】研究不同微波条件对稻谷水分迁移状况、品质、脂肪酶活力、内部结构的影响,从而筛选出最佳微波干燥条件以实现稻谷快速有效干燥,缩短干燥时间。【方法】本文使用不同微波剂量(0.69、1.29、1.92 W·g -1)将稻谷处理至50℃、60℃、70℃后,经过缓苏(不缓苏)处理,对照组样品采用热风60℃,干燥时间为60 min,缓苏4 h进行。研究加工品质、爆腰率及相关理化指标,并通过核磁和扫描电镜观察稻谷水分迁移状况和内部结构的变化。 【结果】微波剂量、稻谷温度是影响品质的关键因素。在微波剂量为1.29 W·g -1,60℃,缓苏条件下稻谷的加工品质较好,爆腰率低至8.65%,碎米率、出糙率、整精米率分别为6.76%、83.9%、68.07%,与热风干燥相比无显著差异。同时微波对脂肪酶活力有显著抑制作用,1.92 W·g -1,70℃,缓苏条件下脂肪酶活力最低(5.65 U),比对照组样品脂肪酶活力低4.65 U。利用隶属度综合评分法对干燥后各项品质评判,1.29 W·g -1,60℃,缓苏条件下稻谷得分排名第3,综合考虑升温速率及各项品质得分,为最适宜的微波处理条件。低场核磁和扫描电镜结果表明,经微波干燥后的稻谷结合水含量下降,并产生明显左迁,水分与其他组分结合地更加紧密;稻谷胚乳细胞破裂及淀粉裸露程度增加,呈放射性排列的结构逐渐消失,内部裂纹增加;复合淀粉粒逐渐崩解,单粒淀粉粒增多。 【结论】微波干燥对稻谷的升温速率、品质以及酶活有显著影响,稻谷中各状态水分和其他组分结合的牢固性更强。干燥中水分散失会引起稻谷内部结构发生不同程度的变化,与热风处理相比,微波处理后样品内部裂隙较小。

关键词: 微波干燥, 水分迁移, 加工品质, 脂肪酸值, 脂肪酶, 稻谷

Abstract:

【Objective】This paper researched the influence of the different microwave conditions on water migration, quality, lipase activity, internal structure of paddy, and it aimed to improve the drying rate of rice, shorten the drying time and select the optimum conditions of microwave drying, realizing fast and efficient drying. 【Method】 In this paper, rice was treated to 50℃, 60℃ and 70℃with additional tempering or no-tempering by the microwave dosage of 0.69, 1.29, 1.92 W·g -1. The quality as well as physical and chemical indexes of paddy were determined, and the changes of water migration and internal structure were observed by LF-NMR and SEM. 【Result】 Microwave dose and rice temperature were key factors that affected rice quality. The processing quality of paddy rice was better under the condition of 1.29 W·g -1, 60℃. The rate of crack, broken rice, brown rice, head rice were 8.65%, 6.76%, 83.9%, and 68.07%, respectively. Whereas, the processing quality of paddy rice had no significant difference with hot air drying. Meanwhile, at the same time, microwave had obvious inhibitory effect on lipase activity. The activity of lipase was lowest (5.65 U) in the tempered condition of 1.92 W·g -1, 70℃, and the results showed that the lipase activity in this condition was 4.65 U less than that under control. By using the membership degree comprehensive scoring method to judge the quality after drying, in the condition of 1.29 W·g -1, 60℃-tempering, the rice score ranked third, therefore, with considering the heating rate and the quality score, it was the most suitable microwave treatment condition. The results of LF-NMR and SEM showed that the water content of paddy rice decreased and gradually moved towards the left. It suggested that water was more tightly bonded to other components. The results of SEM showed that the rupture of the endosperm cells and the degree of starch exposure were increased, the structure of radioactive arrangement gradually disappeared, the composite starch gradually disintegrated, and the single grain and the internal cracks in rice increased. 【Conclusion】 Microwave drying had a significant effect on the heating rate, quality and enzyme activity of rice. The firmness of the combination of water and other components was stronger after microwave. During drying process the loss of water could cause the change of the internal structure of paddy to different degree. Compared with control group, the internal cracks of microwave treated sample were smaller.

Key words: microwave drying, moisture migration, processing quality, fatty acid value, lipase, rice