谷蠹蛀食对玉米中淀粉及油脂品质的影响

Effects of Rhizopertha dominica Infestation on Starch and Oil Quality in Corn

探讨谷蠹不同虫口密度和为害时间对玉米加工品质的影响,为谷蠹蛀食玉米的有效利用和谷蠹的科学防控提供参考。以河南玉米为试材,以谷蠹为试虫,设置不同虫口密度进行为害,测定不同为害期玉米粗淀粉含量、破损淀粉含量、淀粉颗粒形貌、淀粉糊化特性、粗脂肪含量、脂肪酸值、过氧化值、品尝评分值等品质指标。结果表明:随着虫口密度和为害时间的增加,玉米品质指标变化幅度增加;谷蠹为害65 d时,各处理组玉米中粗淀粉减少幅度和破碎淀粉增加幅度都不超过8%,而在为害25 d时脂肪酸值和过氧化值上升幅度都已超过10%。初始虫口密度为15、25头/kg和5头/kg的玉米中淀粉的糊化特性分别在谷蠹为害25 d和45 d时出现明显变化,尤其是衰减值下降超过10%。另外,谷蠹为害会造成玉米淀粉颗粒形态改变,制成窝头颜色加深,表面粗糙,品尝评分值降低。因此,在玉米储藏过程中,应密切监测谷蠹虫口密度,并适时安排出库,合理进行加工,以降低损失。

The effects of different population density and infection time of Rhizopertha dominica on the processing quality of corn were studied in order to provide reference for the effective utilization of corn and control of Rhizopertha dominica.Henan corn was used as the test material,and infected with different initial population densities of Rhizopertha dominica.Then,the crude starch content,damaged starch content,starch particle morphology,starch gelatinization characteristics,crude fat content,fatty acid value,peroxide value and taste score of steamed corn bread were assessed at different infection stages.The results indicated that the magnitude of changes in maize quality indexes increased with the increase of initial population density and infection time.After 65 days of infection,the decrease of crude starch content and increase of broken starch content in all treated corn were no more than 8%;however,the elevation of fat acidity and peroxide value of corn already exceeded 10%after 25 days of infection.The starch gelatinization characteristics of corn with initial infection density of 15,25 heads/kg and 5 heads/kg showed significant changes after 25 and 45 days,respectively,with the breakdown value in particular decreasing by more than 10%.In addition,Rhizopertha dominica infestation could alter the morphology of starch granules in corn and resulted in the produced steamed cornbread with deepened color,rough surface and lower taste score.Therefore,the population density of Rhizopertha dominica should be closely monitored during corn storage,and stored corn should be timely delivered from stock and reasonably processed to reduce its losses.