水气耦合对青皮核桃贮期腐烂的控制与品质保持的效应

Effect of Moisture Loss and Modified Atmosphere Packaging on Decay Control and Quality Maintenance of Green Walnut during Storage

为了探究适当失水与自发气调包装对青皮核桃保鲜的协同效应,本文以‘西扶2号’核桃鲜果为试材,采取0、5%、10%3种果实失重率与PE30、PE50两种自发气调包装(水气耦合)条件复合处理,以0失水加食品保鲜膜包装为对照,(0±0.5)℃下贮藏。结果发现,各处理对果实的保鲜效果和核桃仁品质保持能力均高于对照,以失水10%复合PE50包装处理(10%+PE50)最强,5%+PE30其次。贮藏80 d后10%+PE50的裂果率、腐烂率、褐变指数最低,分别为:2.1%、2.0%、10%,对照分别为:81.6%、42.4%、80.0%;10%+PE50的核桃仁总酚、类黄酮含量、总抗氧化能力最高,均显著高于对照(p<0.05),核桃仁感观品质下降最少,核桃仁的丙二醛(MDA)、过氧化氢含量、酸价、过氧化值最小。贮藏110 d后,10%+PE50的果实腐烂率11%,因褐变指数大于20%,贮藏中止。因此,失水10%复合PE50包装处理被选为最有效的水气耦合条件,能使青皮核桃保鲜期延长至110 d。

In order to investigate the synergistic effect of a combination of appropriate moisture loss and modified atmosphere packaging (MAP) on the preservation of green walnut fruit. Cultivar Xifu 2 fresh walnut fruits were sampled, and treated with three moisture loss rate (0, 5%, and 10%) and two MAP (PE30 and PE50) combinations. The treatment with 0% moisture loss coupled with food-wrapping film packaging served as a control, and all samples were stored at 0 ± 0.5. The results demonstrated improved preservative effect on fresh fruits and the quality maintenance of walnut kernels compared with the control; the best results were obtained using the combination of 10% moisture loss and PE50 packaging (10% + PE50), followed by 5% + PE30. After 80-day storage, the green walnut fruits treated with 10% + PE50 showed the lowest fruit cracking rate (2.1%), decay incidence (2.0%) and browning index (10%), but those indexes of of the control were 81.6%, 42.4%, and 80.0%, respectively. The walnut kernels treated with 10% + PE50 had the highest total phenolic and flavonoid content and total antioxidant activity. The walnut kernels treated with 10% + PE50 showed the smallest decline in the sensory quality, and the lowest acid value, peroxide value, and malondialdehyde (MDA) and H2O2contents. After 110-day storage, the decay rate of the fruits treated with 10% + PE50 was 11%, and the experiment was stopped because the browning index was more than 20%. In conclusion, 10% moisture loss coupled with PE50 packaging was determined to be the optimal combination of moisture loss and MAP, which can extend the shelf life of green walnut up to 110 days. © 2015, South China University of Technology. All right reserved.