微酸性电解水结合壳聚糖对水蜜桃护色保鲜的效果

为了防止水蜜桃(Prunus persicaL.Batsch)采后的果肉颜色变化而严重影响其商品价值。该研究以南汇水蜜桃为材料,分别利用自制羧甲基壳聚糖复合保鲜剂,以及微酸性电解水对水蜜桃进行护色保鲜处理,并对冷藏条件下(2℃)水蜜桃果肉颜色及与颜色品质变化相关的指标进行了检测,同时还利用核磁共振成像(MRI)合成T2-MAP图研究了冷藏开始和结束后水蜜桃内部变化的规律。结果表明,在贮藏结束后,对照组果肉颜色的L*值、H*值、C*值分别是羧甲基壳聚糖复合保鲜剂和微酸性电解水处理组的85%～91%、85%～93%和114%～122%(p<0.05)。显然,羧甲基壳聚糖复合保鲜剂和微酸性电解水由于可以抑制水果自身乙烯的产生,减少水果的细胞膜透性和T2-MAP图中T2弛豫常数的变化,降低了多酚氧化酶(PPO)活性的增加速度,减少了酚类物质的累积,进而延缓了果肉的变色。另外,与仅用电解水处理相比,结合羧甲基壳聚糖处理具有较好的护色保鲜效果。通过该研究,可以为提高采后南汇水蜜桃的果肉护色保鲜效果提供参考。

Effects of slightly acidic electrolyzed water and carboxymethyl chitosan preservative on flesh discoloration of peaches

In order to reduce flesh color changes in Nanhui peach (Prunus persica L. Batsch), which seriously affect their commercial value, carboxymethyl chitosan preservative and slightly acidic electrolyzed water were used to preserve Nanhui peaches. Changes in flesh color, and the quality characters related to flesh color were assayed periodically during storage at 2oC. T2-MAP made by magnetic resonance imaging (MRI) was used to check the inner quality of peaches at the beginning and end of the storage time. The results showed that the L* values, H* values, C* values of the control samples were 85%-91%, 85%-93% and 114%-122% higher than the two treated samples at the end of storage time, respectively (p<0.05). Compared with the control group, both carboxymethyl chitosan preservative and slightly acidic electrolyzed water can suppress ethylene production, decrease cell membrane permeability and changes in T2 relaxation constant, delay the increase in PPO activity and the accumulation of total phenolic compounds, thus decrease the peach flesh discoloration. Compared with slightly acidic electrolyzed water treatment, carboxymethyl chitosan preservative treatment was more effective in maintaining the quality of Nanhui peaches.