Study On The Effect Of Micro Encapsulated Compound Essential Oil On The Preservation Of Rice

Rice, one of staple food in China, is very easy to mildewing during storage, thus huge losses is repeated every year. At present, there is no natural product against rice mould can be put into practice. Therefore, it is an urgent need for current times to develop a safe and efficient one. This paper selected cinnamon essential oil and litsea cubeba oil out of 9 kinds of essential oil as tested materials for their good antifungal effect against rice Penicillium and Aspergillus niger. The collaborative antifungal effect of mixed essential oil were discussed to determine their optimal proportion. Then, the preparation technology of microencapsulation for mixed essential oil was optimized, and the optimum technology was obtained. Finally, the compound essential oils microencapsulated was tested as rice fresh-keeping agent to explore its effect on rice quality during storage. It was preliminary confirmed that it could delay the rice quality deterioration.The results were as folio wings:1.In nine kinds of single essential oil, the cinnamon, cloves, litsea cubeba oil showed a better effect against inhibiting mold. When the ratio of cinnamon essential oil to litsea bubeba essential oil was 3:1(v/v), it had the best inhibitory effect on the Pencillium and Apergillus niger of rice. The minimum inhibitory concentration (MIC) reached 0.1 μL/mL, it decreased 20 to 180 times than that of single essential oil.2.The preparation technology of microencapsulation (compound condensation method) was optimized through single factor experiment then orthogonal experiment, taken gelatin and arabic gum as wall material and composite of cinnamon-litsea cubeba oil as core material, with the embedding rate as the evaluation index. The experimental results showed that the optimum embedding rate of microcapsules reached 89.98% as the ratio of core to wall was 5:3, wall-material concentration was 1.6%, the ratio of wall composition(gelatin/arabic gum) was 5:3, and pH was 5.4. The microencapsulated powder was stored at 25 ℃ for 20 h in a drying oven, the retention rate still was kept at 76%, whereas the retention rate of the compound essential oil non-microencapsulated was only 21%, the former was 3.6 times of the latter.3. The microencapsulated powder of compound cinnamon-litsea cubeba essential oil was kept in a sealing environment together with rice to explore its effect on rice quality under conditions of high temperature and high humidity aiming to accelerating the rice aging. In this course, several indexes, including rice fatty acid, heating water absorption rate, soaking liquid pH value, volume expansion, and starch-iodine-blue, was measured periodically. The result showed that microcapsules of compound cinnamon-litsea cubeba essential oil exhibited an excellent effect on delaying rice deterioration.