采前翠贝喷洒及采后壳聚糖涂膜对厚皮甜瓜低温贮藏期间冷害及品质的影响
Effect of preharvest Stroby spray and/or chitosan postharvest coating on chilling injury and quality of muskmelon during cold storage
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摘要: 厚皮甜瓜(Cucumis melo L.)对低温敏感,在低温条件下贮藏易发生冷害,导致果实品质下降,货架期缩短。本实验以"玛瑙"厚皮甜瓜为材料,研究了在果实发育期(幼果期、膨大期、网纹形成期及采前48 h)单独400 mg/L翠贝4次喷洒、采后单独1.5%壳聚糖涂膜及采前、采后结合处理对果实低温(5℃)贮藏期间冷害及品质的影响。结果表明,采前单独翠贝喷洒或结合采后壳聚糖涂膜均可有效减轻贮藏期间的厚皮甜瓜冷害,明显降低果实细胞膜渗透率和丙二醛(MDA)含量,其中以采前翠贝处理对冷害的控制效果最好,在贮藏第21 d时,处理果实的冷害指数仅相当于对照组的1/3。同样,以上3种处理还延缓了贮藏期间果实可溶性固形物(TSS)和可滴定酸(TA)的下降,保持了果实良好的品质。其中,采前翠贝处理对维持果实的硬度和亮度、色泽效果较好;而采后壳聚糖涂膜对延缓果实TSS下降,降低失重率的效果较为突出。Abstract: Muskmelon(Cucumis melo L.) was sensitive to low temperature,which likely causes chilling injury(CI)during cold storage,and makes a decline in quality,resulting in shelf life shortened. In this study, ‘Manao'muskmelon was used to investigate the effect of 4 time 400 mg/L Stroby spray alone during the fruit development period(young fruit,swelling period,netting period and 48 hours before harvest) and/or 1.5% chitosan postharvest coating on quality and CI of muskmelon during low temperature(5 ℃) storage.The results showed that preharvest Stroby spraying or postharvest chitosan coating alone or their combination effectively reduced the CI of muskmelon,significantly lowered the membrane permeability and the content of MDA in fruit,and that the effect of preharvest Stroby spraying alone was the best as the fruit CI index of this treatment was only about 1/3 of the control fruit. Similarly,anyone of the above three treatments also delayed the decline of TSS and TA,maintained good fruit quality during storage. Among them,preharvest Stroby spraying alone was the best to maintain higher fruit firmness,L* and h° values. Postharvest chitosan coating had the best effect to alleviate the decline of TSS and fruit weight loss.