高湿低温环境中臭氧对冬枣生理生化的影响

软化褐变和腐烂是冬枣贮藏存在的主要问题。研究了高湿低温贮藏环境中,臭氧(浓度1~2 mg／m3,作用时间15min,8 h释放1次)对冬枣的硬度与维生素C含量、淀粉含量和淀粉酶活性,过氧化物酶(POD)活性和丙二醛(MDA)含量的影响,并统计了冬枣贮藏60 d和模拟运输后再贮藏7 d的脆果率等理化指标。结果发现,湿冷环境中,臭氧可以延缓冬枣硬度、维生素C含量和淀粉含量的下降速度,75 d时臭氧处理冬枣的硬度和维生素C含量分别比对照组高出13.4％和14.3％,淀粉含量比对照组高出18.6%(60 d);臭氧可以降低淀粉酶活性和MDA含量的上升速度,抑制过氧化物酶活性,60d时臭氧处理组比对照组枣果的淀粉酶活性和MDA含量分别低34％和92％,过氧化物酶活性峰值比对照组的低27.3％;贮藏60 d后臭氧处理冬枣的脆果率比对照组高出25％,说明湿冷环境的臭氧贮藏可以明显提高冬枣的贮藏效果。

A Study on Changes of Post-harvest Physiology of Dongzao in Humid cool and Conventional Cold Room Conditions

Softening and rotting were main problems in long-term storage of Dongzao (Ziaiphus jujube Mill. cv. Dongzao). Under humid-cool storage conditions, effects of ozone (concentration of 1-2 mg/m3, treated for 15 min, once every 8 h) on the firmness and vitamin C content,starch content and amylase activity, peroxidase (POD) activity and malanaldehyde (MDA) content of Dongzao were studied. After storage for 60 d, crisp fruit rate, rotted rate, softened rate, and edible rate were examined, and then simulating transport and restoring for 7 d, these indexes were valued again. The results showed that ozone treatment in humid-cool conditions could retard reducing of firmness, vitamin C, and starch content of Dongzao. After 75 d, the reduced rate of firmness with ozone treatment and control reached 17.7% and 31.1%, and that of Vitamin C content reached 29.1% and 14.8%, respectively. It was 18.6% that the starch content with ozone treatment was lower than that of control in 60 d. Ozone treatment could inhibit increasing of amylase activity, POD activity and MDA content of Dongzao. After 60 d of storage, the increased rate of amylase activity on ozone treatment and control reached about 1.31 time and 97%, and that of MDA content reached about 1.44 time and 52%, respectively. The peak value of POD activity on ozone treatment and control was 1.6 U/g·min and 1.93 U/g·min. The crisp fruit proportion of Dongzao treated with ozone exceeded control by 25% in 60 d. All these illustrated that ozone storage can improve the storage quality of Dongzao.