谷蠹侵害稻谷后其储藏品质变化研究

Changes in the storage quality of rice after been infested by lesser grain borer

以粳稻谷为研究对象,选择不同的虫口密度(0、10、20、50、100和200头/500 g),在(30±1)℃与(75%±1%)RH条件下,对稻谷进行侵害实验,测定不同感染时间稻谷的水分、脂肪酸值、电导率、过氧化物酶、丙二醛等储藏品质指标,探讨不同虫口密度和感染时间下谷蠹对稻谷储藏品质的影响。结果表明:随着虫口密度的增加和侵害时间的延长,稻谷中的水分和过氧化物酶(POD)逐渐增加,而脂肪酸值、丙二醛和电导率逐渐降低,其中感染50 d时,各虫口密度感染的稻谷其过氧化物酶无明显变化,而50d后,迅速下降;水分和POD与感染时间呈极显著负相关,脂肪酸值、丙二醛和电导率与感染时间呈极显著正相关;脂肪酸值与虫口密度呈极显著正相关,电导率和丙二醛与虫口密度呈显著正相关,POD与虫口密度相关性不显著;脂肪酸值、POD、电导率、丙二醛各指标之间均呈极显著相关,水分除与POD呈显著正相关外,与其它各指标均呈极显著负相关;当虫口密度为50头/500 g时,感染稻谷30d后其品质便开始发生变化,因此,当稻谷中谷蠹虫口密度较大时,需要在30d内进行杀虫处理,以避免其品质遭受到大的影响。

Taking japonica rice as the research object,the hazard experiment of rice was carried out under the different population density(0,10,20,50,100 and 200 head/500 g)and the storage conditions such as the temperature of(32±1)℃and relative humidity of 75%±1%,in order to investigate the effect of infestation by lesser grain borer on the storage quality of rice,including moisture content,fatty acid value,conductivity,peroxidase activity and malondialdehyde and other storage quality indexes of rice,at different infection time.The results showed that with the increase of population densities and the prolongation of infestation time,moisture content and peroxidase in rice increased gradually,while fatty acid values,malondialdehyde,and conductivity gradually decreased,and there was no obvious change in peroxidase for each samples with different population density when being infected for 50 days;after 50 d,it dropped rapidly.Moisture content and POD were significantly negatively correlated with infection time,and fatty acid values,malondialdehyde,and conductivity were significantly positively correlated with infection time.There was a significant positive correlation between fatty acid values and density of insect populations,and there was a significant positive correlation between conductivity and malondialdehyde and population density,and there was no significant correlation between POD and population density.The Fatty acid value,POD,conductivity,and malondialdehyde were all significantly associated with each other.Except for a significant positive correlation with POD,moisture content had a significantly negative correlation with other indicators.When the population density was 50 heads/500 g,the quality of rice began to change after 30 days of infection.Therefore,when the population density is large,the insecticidal treatment must be performed within 30 days to avoid a large impact on its quality.