Effect on Sitophilus oryzae infestation on amylose content and weight loss of eight rice varieties

Abstract

Sitophilus oryzae is one of the primary pests that causes severe damage to food products. Damage of the grains cause a drastic dropping of rice quality, which significantly affected our rice industry. The amylose content and weight loss are two components that are affected due to the S. oryzae infestation. In this study, eight rice varieties namely Thai Pathumthani Fragrant White Rice 100%, Vietnam Long Grain White Rice 5%, Pakistan Basmathi Long Grain White Rice PK 385, Indian Steam Pusa 1121 Basmathi LGWR, Thai White Rice, Pakistan White Rice, Cambodian Fragrant Sen Kro Oub 5%, and Vietnamese White Fragrant Rice 2% were collected to investigate the amylose content and weight loss after six-month durations of the S. oryzae infestation. ANOVA analysis has shown a significant value, p-value=0.00, p <0.05 for the relationship between amylose content and rice varieties, whereas the weight loss in the eight rice varieties also showed a significant value, p-value= 0.00, p< 0.05. The Pakistan White Rice has recorded the highest percentage of weight loss (55.8%), while Cambodian Fragrant Sen Kro Oub 5% showed the lowest percentage of weight loss (23%). Despite the significant weight loss, the amylose content in each rice variety has showed a low rate, 2-9%. Results obtained from this study are considered as a fundamental data to strategize the S. oryzae pest management to make sure the continuity of rice supply for Malaysia.