真空预冷与雾化ε-聚赖氨酸共处理对采后上海青品质的影响

Effect of Vacuum Pre-Cooling Co-Treated with Atomized ε-Polylysine on Postharvest Quality of Pakchoi

摘要:

为探究真空预冷与ε-聚赖氨酸(ε-polylysine,ε-PL)共处理对上海青品质的影响,分析了真空预冷、真空预冷结合喷雾补水、真空预冷与雾化ε-PL共处理对低温流通过程和货架期间上海青外观品质、抗氧化物质、营养成分及有害物质含量的变化。结果表明:与对照组相比,单独真空预冷能够保持上海青较好的品质,但会导致叶片表面严重失水萎蔫,预冷后失水率达到4.45%；而真空预冷结合喷雾补水能改善组织的失水问题,失水率较单独真空预冷低了61.27%；相比之下,真空预冷与雾化ε-PL共处理不仅能降低单独真空预冷导致的失水问题,而且明显延缓了上海青的黄化程度。在货架期结束时,真空预冷与雾化ε-PL共处理组的总叶绿素质量比为0.74g/kg,分别是对照组、真空预冷及真空预冷结合喷雾补水组的2.87、2.00、1.56倍；真空预冷与雾化ε-PL共处理还显著减缓了抗氧化物质类胡萝卜素、抗坏血酸、叶酸和总酚含量的下降,维持了营养物质可滴定酸、可溶性糖和可溶性蛋白的较高含量,同时还有效抑制了亚硝酸盐及丙二醛的积累。真空预冷与雾化ε-PL共处理可有效延缓采后上海青的黄化衰老进程,维持其较好的营养品质。

Abstract:

To explore the influence of vacuum pre-cooling co-treated with atomized ε-polylysine (ε-PL) on the quality of pakchoi (Brassica chinensis L.), the effects of vacuum pre-cooling, vacuum pre-cooling co-treated with atomized water or ε-PL on the changes in the appearance quality, antioxidant substance, nutrient composition, and harmful substance contents of pakchoi during low temperature circulation and shelf life were analyzed. The results showed that vacuum pre-cooling alone maintained the better quality of pakchoi compared with control, but caused serious water loss and wilting of leaf surface, and the water loss rate after precooling reached 4.45%, while vacuum pre-cooling combined with atomized water group could reduce the water loss rate by 61.27%. In contrast, vacuum pre-cooling co-treated with atomized ε-PL could not only decrease the water loss caused by vacuum pre-cooling alone, but also obviously delay the yellowing degree of postharvest pakchoi. The total chlorophyll mass ratio in vacuum pre-cooling co-treated with atomized ε-PL group was 0.74g/kg at the end of shelf-life, which was 2.87,2.00, and 1.56 times higher than that of control group, vacuum pre-cooling group, and vacuum pre-cooling combined atomized water group, respectively. Moreover, vacuum pre-cooling co-treated with atomized ε-PL significantly slowed down the decrease of antioxidant such as carotenoids, ascorbic acid, folic acid, and total phenols, maintained higher levels of titratable acid, soluble sugar, and soluble protein, and effectively inhibited the accumulation of nitrite and malondialdehyde. Vacuum pre-cooling co-treated with atomized ε-PL could effectively delay the yellowing and senescence process, and maintain better nutritional quality of postharvest pakchoi.