Effectiveness of Cinnamon Oil Embedded Chitosan–Gelatin Film in Inhibiting Rhizopus oryzae, R. microsporus, and Syncephalastrum racemosum and Controlling Rice Weevil Infestation on Paddy Rice

Rice (<i>Oryza sativa</i> L.) is a staple food globally, providing a critical food for the majority of the Asian population. However, it exposes risks during post-harvest storage, threatening substantial losses in rice quality and quantity. Hence, this study developed a cinnamon oil-chitosan:gelatin film (CO-C:G film) with the parameters as the chitosan:gelatin ratio (C:G = 1:1 and 1:2), cinnamon oil (CO) contents (0.75, 1.0, 1.25, 2.5, and 5.0%) and thickness film levels (0.165, 0.183, and 0.287 mm) to inhibit three fungal species, <i>Rhizopus oryzae</i> 01, <i>R. microsporus</i> 01, and <i>Syncephalastrum racemosum</i> 01, and control rice weevil infestation on paddy rice at a variety of water activities, such as 0.71 a_w and 0.95 a_w, at room temperature. The results revealed that at 0.95 a_w, the fungal growth rate and rice weevil's mortality were impacted significantly by all parameters of the CO-C:G film (<i>p</i> < 0.05). Especially, the CO-C:G film with 1.25% CO and C:G = 1:1 at a thickness film of 0.287 mm inhibited all observed fungi and rice weevils better than the CO-C:G film's other parameters. The inhibition of the CO-C:G film for these fungi ranged from 66% to 72.6%. Likewise, 80-100% of rice weevils were mortal when paddy rice was treated with the CO-C:G film on the 12th or 15th day of treatment depending on the water activity of paddy rice grains. The findings of this study provide insights for researchers, agricultural experts, and the food industry, highlighting the need to establish effective and sustainable strategies for rice preservation.