| Rice(Oryza sativa L.) is one of the main grain crops in China. It is easy to aging and mildew because of moisture absorption at the high temperature and humidity weather condition in the south of China, as a result, it brings a large amount of waste. How to keep the rice fresh in the process of storage and logistics is a very important subject in China. It is popular of using chemical mould inhibitor sodium diacetate for keeping the rice fresh at present. With the green consumption consciousness getting stronger, there is a new trend to keep the rice fresh by the plant extracts, instead of sodium diacetate. Different plants were selected as research materials in this work. Systematic studies were carried out on the extraction, antifungal activity and antioxidant activity of the screening plant.According to the results of the antifungal tests, ginger extracts showed the strongest antifungal activity against the penicillium from the rice among the ten different plant extracts, both the water extract and ethanol extract displayed strong inhibiting ability. Component analysis of the ginger extracts with water, 60% ethanol, 35% acetone or methanol was investigated. The results showed that the water extract had much more polysaccharides, beside the methanol extract had much more gingerols.The ginger extracts were tested against the penicillium by the agar well diffusion assay. Gingerols displayed strong antifungal activity, ginger polysaccharides showed no antifungal activity. There were no significant differences of antifungal properties among the four solvent extracts. The MIC value of the water extract is (0.006±0.002)g/mL, and the MIC value of sodium diacetate is (0.005±0.001)g/mL. The results showed that mould inhibitor would have effect when the concentration reached 5mg/mL.The antioxidant activity of ginger extracts were investigated using different antioxidant tests in vitro. The results showed that ginger extracts displayed strong antioxidant properties, and the antioxidant activity would increase with the concentration of samples increasing. The reducing power of samples were followed this order: methanol extract > ethanol extract > acetone extract > water extract, gingerols'reducing power was between BHT and Vc, ginger Polysaccharides had no reducing power. The results of ginger extracts'radical-scavenging activities showed that the IC50 of water extract, ethanol extract, acetone extract, methanol extract, gingerols and Vc was 52.31μg/mL, 42.87μg/mL, 51.13μg/mL, 37.62μg/mL, 4.67μg/mL and 4.50μg/mL. The antioxidant activity in preventing the peroxidation of linoleic acid followed the order: Vc> gingerols > methanol extract > ethanol extract≈acetone extract > water extract. The ginger extracts coating rice could lower the fatty acid value of rice and delay rice aging effectively.The ratio of the new rice preservation is water extract of ginger: trehalose: Vc=2: 1: 0.5. 1g preservation was dissolved in 100mL water,1mL solution could coat 50g rice. The cooking properties and storing effects of the coated rice were evaluated, the results indicated that the moldproof ability of the rice preservation designed by this work was all square with simulated saled one. Chemical mould inhibitor sodium diacetate could be instead by the water extract of ginger. The results of sensory evaluation showed that the sensory properties of the coated rice was similar to the blank. After one week accelerated aging, the taste value of the coated rice decreased only slightly. The new rice preservation could play an important role in mouldproof and age-delaying.
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