玉米象侵害后的稻谷的加工精度对大米理化特性和食用品质的影响
Effect of processing accuracy of maize weevil infested paddy on physicochemical properties and eating quality of rice
-
摘要: 为探究玉米象侵害后的稻谷的加工精度对大米理化特性和食用品质的影响以及加工精度对玉米象侵蚀的抑制程度,以玉米象侵害后的稻谷为研究对象,以未被侵害的稻谷为对照,将被侵害的稻谷分别加工为糙米、适碾大米和精碾大米后,用PE包装袋密封并在30 ℃、RH 75%条件下储藏30 d,储藏期间定期取样并对大米的脂肪酸值、丙二醛(MDA)含量、α-淀粉酶活性、过氧化物酶(POD)活性、过氧化氢酶(CAT)活性等生化指标及其所制米饭的质构特性和蒸煮品质进行测定与分析。结果表明:随着储藏时间的延长,所有处理组大米样品的脂肪酸值、α-淀粉酶活性和MDA含量均呈上升趋势,POD活性和CAT活性均呈下降趋势;其对应米饭的食用品质逐渐下降,硬度上升,黏性与弹性下降;米饭蒸煮特性中吸水率和膨胀率上升,pH值与米汤固形物含量逐渐下降;与对照样加工的大米相比,虫蚀样加工得到的大米的品质劣变更加明显;随着大米加工精度的提高,样品的脂肪酸值、MDA含量以及酶活逐渐下降,且随着加工精度的提高品质劣变速度逐渐降低。玉米象对稻谷的侵害会造成大米储藏品质劣变加速,而稻谷的加工会碾磨掉部分虫卵,减缓玉米象侵害对大米储藏品质的影响,且随着加工精度的提高抑制效果增强。适碾与精碾对害虫的侵害均有抑制效果且对大米食用品质的影响并无显著性差异,适碾大米保留了部分皮层和糊粉层,因此储藏条件适宜时适碾大米可作为更优的储藏方式。Abstract: In order to investigate the effects of processing accuracy of maize weevil infested paddy on the physicochemical properties and food quality of rice and the degree of inhibition of maize weevil infestation by processing accuracy, the present study was conducted on maize weevil infested paddy, where uninfested paddy was set as the control. The infested paddy was processed into brown rice, suitable milled rice and fine milled rice, and then sealed in PE bags and stored at 30 ℃ for 30 d. During the storage period, samples were taken regularly and the biochemical indexes such as fatty acid value, malondialdehyde (MDA) content, α-amylase activity, peroxidase (POD) activity, catalase (CAT) activity, and the textural and cooking characteristics of the rice were measured and analyzed. The results showed that: with the prolongation of storage time, the fatty acid value, α-amylase activity and MDA content of rice samples from all treatment groups showed an increasing trend, and the POD activity and CAT activity showed a decreasing trend; the edible quality of the corresponding rice gradually declined, the hardness increased, and the viscosity and elasticity declined; the water absorption and expansion rate of the cooking characteristics of the rice increased, and the pH value and the content of the rice broth solids gradually declined; the quality deterioration of the rice obtained from the worm-extraction sample was more obvious when compared with the control sample; the quality deterioration of the rice obtained from the worm-extraction sample gradually decreased with the improvement of the precision of rice processing, and it was more obvious with the improvement of processing precision. Compared with the rice processed by the control sample, the quality deterioration of the rice processed by the worm-eaten sample was more obvious; with the increase of the processing precision of the rice, the fatty acid value, MDA content and enzyme activity of the sample gradually decreased, and the speed of quality deterioration gradually decreased with the increase of the processing precision. Maize weevil infestation on paddy accelerated the deterioration of the storage quality of rice, but the processing of paddy excluded some of the eggs, slowing down the impact of maize weevil infestation on the storage quality of rice, and the inhibitory effect was stronger as the precision of the processing increased.