氯化钙和抗坏血酸处理对鲜切苹果品质和褐变的影响

Effects of CaCl_2 and AsA Treatments on Quality and Browning in Fresh-Cut Apple

【目的】明确苹果鲜切后品质和褐变的变化规律;探讨外源抗坏血酸(AsA)与氯化钙(CaCl2)处理的生理作用,筛选理想的保鲜剂。【方法】取成熟期富士苹果果实为试材,经去皮、去核后,切分成厚度约为1mm的果片,分别于蒸馏水、1.0%AsA、1.0%CaCl2水溶液中浸泡5min,吸干水分后,用培养皿盛装,置于室温(25℃)条件下于0、0.25、0.5、1、2、4、6、8、10、12h后进行褐变指数、失重率调查和可溶性总糖、可滴定总酸、抗坏血酸(AsA)、总酚、丙二醛(MDA)含量测定及多酚氧化酶(PPO)、过氧化物酶(POD)活性测定。【结果】苹果切分后,蒸馏水浸泡的果片褐化迅速、褐变严重,水分及其它易挥发性物质大量散失,可溶性总糖、可滴定总酸、抗坏血酸和总酚含量下降,糖酸比值上升,PPO、POD活性迅速升高,MDA含量先升高后下降。1.0%AsA和1.0%CaCl2处理均能有效延迟果肉褐化进程,降低褐变程度,抑制水分及其它易挥发性物质、可溶性总糖、可滴定总酸、抗坏血酸和总酚含量的下降,延迟糖酸比值上升以及PPO、POD活性高峰的到来,MDA含量升高。两者相比,1.0%CaCl2的处理效果更好。初步建立了鲜切苹果产品质量评价体系,可溶性固形物、可溶性总糖、可滴定总酸、酚类物质含量高,易挥发性物质散失速率低,不易褐变的品种属于良好的鲜切苹果加工品种。【结论】1.0%CaCl2是鲜切苹果理想的保鲜剂及褐变抑制剂。

【Objective】 The changes of quality and browning of the fresh-cut apples,the physiological roles of exogenous ascorbic acid （AsA） and calcium chloride （CaCl2） were studied for screening of an ideal preservative. 【Method】 Ripening ＇Fuji＇ apple fruits were used as materials and peeled,cored,and then cut into slices about 1mm; after soaked for 5 min in distilled water,1.0% AsA and 1.0% CaCl2 aqueous solution,wiped the surface water,then put in culture vessel under 25 ℃,and at 0,0.25,0.5,1,2,4,6,8,10,12 h,the browning index and the rate of weigh loss were surveyed,the contents of total soluble sugars,total titratable acids,ascorbic acid （AsA）,total phenols and malondialdehyde （MDA） were analyzed,and the polyphenol oxidase （PPO） and peroxidase （POD） activities were detected. 【Result】 The quality and physiological characteristics of the fruit slices soaked in distilled water were changed dramatically,flesh browning was rapid and serious,water and other volatile material released largely,the content of total soluble sugars,total titratable acids,AsA and total polyphenols decreased,the ratio of sugar and acid increased,the activities of PPO and POD rose rapidly. The content of MDA increased first and then decreased. 1.0% AsA and 1.0% CaCl2 treatment could effectively delay the process of flesh browning,reduced browning degree,inhibited decreasing of water,volatile substances,total soluble sugars,total titratable acids,ascorbic acid and total polyphenols,delayed sugar/acid ratio increase,as well as PPO,POD activities in the peak arrival,the content of MDA increased. In general,the treatment of 1.0% CaCl2 was better. In addition,a quality evaluation system of fresh-cut product was initially established. Varieties with high content of soluble solids,total soluble sugar,total titratable acids and phenolic substances,low volatile matter loss rate,and browning-resistance are good apple varieties for fresh-cut apples processing.【Conclusion】 1.0% CaCl2 is a better preservative reagent and browning inhibitor in fresh-cut apples.