稻谷储藏过程霉菌挥发性物质和品质分析

黑曲霉、黄曲霉、白曲霉、产黄青霉四种常见霉菌侵染稻谷储藏28 d,测定探究不同稻谷染霉前后外观质量、酶活、糊化特性及挥发性物质变化。结果表明,白曲霉、黄曲霉、黑曲霉的生长速度较快。染霉稻谷质量整体变化较大,染霉稻谷的出糙率及整精米率下降明显,不完善粒明显增加,染霉稻谷质量低于国家三级粳稻谷要求。并且稻谷的酶活受染霉影响变化明显,导致直链淀粉含量增加,同时产生酸败的气味,稻谷整体品质不佳。在扫描电镜的测试中发现受霉菌感染的稻谷,虽经去壳磨康处理,但菌丝体依旧附着大米表面。侵染霉菌的稻谷储藏过程中挥发性物质发生变化,黑曲霉侵染的稻谷酯酸类物质相对含量在3.45%~11.89%,与对照组相比降低约2.38%~4.00%;产黄青霉侵染的稻谷烃类相对含量在54.45%~72.45%,与对照组相比增加了约0.24%~3.44%。本实验为我国预防稻谷储藏霉染探究提供理论基础,综合有效地降低霉染稻谷对粮食的浪费。

Analysis of Mould Volatile Substances and Quality during Rice Storage

Four common moulds(Aspergillus niger,Aspergillus flavus,Aspergillus oryzae and Penicillium chrysogenum)were inoculated with rice for 28 d to determine the appearance quality,enzyme activity,gelatinization characteristics and volatile substance changes of different rice before and after mildewed. The results showed that the growth rate of Aspergillus oryzae,Aspergillus flavus and Aspergillus niger grew faster. The overall quality of the mildewed rice changed a lot when roughness and the rate of whole mildewed rice decreased,and the imperfect grain increased significantly,which result in the quality of mildewed rice was lower than the national third-grade rice paddy requirement. Moreover,the enzyme activity of rice was significantly affected after mildewed,which led to an increase in the content of the direct starch and a rancid smell. The overall quality of the rice was bad. It was found that the mycelium of rice infected by moulds still adhered to the surface of rice,though it was treated by shelling and grinding by SEM. The volatile matter changed during the storage of rice infected with moulds. The relative content of rice lipids infected by Aspergillus niger was 3.45%~11.89%,which was reduced by about 2.38%~4.00% compared with the control group. The relative content of hydrocarbon in rice infected by Penicillium chrysogenum was 54.45%~72.45%,which increased by 0.24%~3.44% compared with the control group. This experiment would provide a theoretical basis for the study of preventing mildew contamination in rice storage in China,and comprehensively and effectively reduces the waste of mildew contaminated rice to food.