冻藏处理对“香玲”核桃果实贮藏品质与生理的影响

以"香玲"核桃果实为试材,研究不同冻藏温度(0℃、-1℃、-20℃、先-40℃冷冻48 h后转移至-20℃)对其贮藏期间感官品质、含水率、脂肪含量、过氧化值、总酚含量、多酚氧化酶(PPO)和过氧化物酶(POD)活性等指标的变化,以期为核桃果实冻藏技术的应用提供参考依据和技术支持。结果表明:-20℃与-40℃冻藏处理有效地抑制了核桃果实的褐变,延缓了种仁脂肪的降解,二者之间感官品质无显著差异;-20℃更好地维持了种仁脂肪含量和油脂的品质,过氧化值较低,种仁POD活性显著高于对照和其它处理,青皮的POD活性均值最低;-1℃能够短期保持核桃果实的品质,1个月后青皮发生冷害加速褐变,粗脂肪含量快速降低。因此-20℃为试验条件下核桃果实的适宜冻藏温度。

Effects of Frozen Treatments on Quality and Physiology of'Xiangling'Walnut Fruits During Storage

‘Xiangling’ walnut fruits were used as test materials, the effects of different freezing temperatures(0 ℃,-1 ℃,-20 ℃,-40 ℃ for 48 hours firstly and then-20 ℃) on the changes in the sensory quality, moisture content and fat content, peroxide value, total phenol content, PPO and POD activities were studied.In order to provide theoretical reference and techincal support for the application of walnut fruit storage technology.The results showed that-20 ℃ and-40 ℃ treatments effectively inhibited the browning of walnut fruits and delayed the degradation of fat in kernel.However,no significant difference in sensory quality was detected between them.Frozen storage at-20 ℃ maintained the fat content and oil quality better,the lower PV and the POD peak in kernel was significantly higher,but the average POD activity in green husk was lower than those of the control and other treatments.The quality of walnut fruits kept only for a short period and the fat content promptly decreased in-1 ℃ treatment.AS for the green husk,the cold damage accelerated browning and the crude fat content decreased rapidly after one month.Therefore,-20 ℃ were identified as the suitable freezen storage temperature for walnut fruits.