‘软儿梨’常温贮藏和冻融过程中糖类的变化

Changes in Carbohydrate Content of‘Ruaner Pear’During Ambient Temperature Storage and Freezing-thawing Period

以‘软儿梨’为试材,采用分光光度法和高效液相色谱等方法,研究了常温贮藏及冻融对可溶性固形物、淀粉、淀粉酶及果糖、葡萄糖、蔗糖和山梨醇等指标的影响,以期为‘软儿梨’的采后贮藏和加工提供参考依据。结果表明:常温贮藏条件下‘软儿梨’可溶性固形物含量随贮藏时间延长而呈现上升趋势,而解冻过程出现先增加后降低的趋势,并在第4天可溶性固形物含量最高,且在后熟过程中可溶性固形物含量始终高于常温后熟;2种方式后熟过程中‘软儿梨’淀粉含量呈明显下降趋势,淀粉酶含量均出现先上升后迅速下降的趋势,冻融过程中淀粉含量始终高于常温后熟;常温后熟过程中果糖、葡萄糖和蔗糖含量呈“上升-下降”的趋势,而山梨醇含量始终呈下降趋势,在解冻过程中果糖含量始终呈现上升趋势,但上升较为缓慢,而蔗糖含量始终呈现下降趋势,葡萄糖和山梨醇含量与常温后熟变化趋势相同。冻融后熟可明显缩短后熟时间,显著提高果实中可溶性固形物含量,但其淀粉的降解没有常温后熟充分,可溶性糖含量在2种后熟过程中变化趋势有所差异,但最终对于糖含量的影响并不明显。

Taking‘Ruaner Pear’as the test material,the effects of normal temperature storage and freezing-thawing on soluble solids,starch,amylase,fructose,glucose,sucrose and sorbitol were studied by spectrophotometry and high performance liquid chromatography,in order to provide reference for the post harvest storage and processing of‘Ruaner Pear’.The results showed that the soluble solids content of‘Ruaner Pear’increased with storage time,and increased first and then decreased during thawing,and the highest value of soluble solids appeared on the 4day,and the soluble solids content was always higher than that of‘Ruaner Pear’during post-ripening.The starch content of‘Ruaner Pear’showed an obvious downward trend but amylase content showed an upward trend and a rapid downward trend,and the starch content in freezing-thrawing process was always higher than normal temperature.During the normal temperature storage,fructose,glucose and sucrose showed a trend of the rise and fall,but the content of sorbitol was always a downward trend.In the process of thawing fructose presented a trend of increasing all the time,but it increased more slowly,and sucrose showed a trend of decline,glucose and sorbitol showed same trends under normal temperature.Experimental results showed that post-ripening time could be significantly shortened after freezing-thawing,and soluble solids content in fruits could be significantly increased,but starch degradation was not as sufficient as post-ripening at room temperature.The variation trend of soluble sugars in the two post-ripening processes was different,but the final effect on sugar content was not obvious.