壳聚糖-海藻酸钠/纤维素纳米晶多层包装对鲜切雪梨保鲜效果及呼吸代谢的影响

Effects of Chitosan-Sodium Alginate/Cellulose Nanocrystal Multilayer Packaging on Preservation and Respiration Metabolism of Fresh-Cut Pyrus Nivalis

将壳聚糖(Chitosan,CTS)-海藻酸钠(Sodium alginate,SA)/纤维素纳米晶(Cellulose nanocrystals,CNC)多层纳米复合膜用于包装鲜切雪梨,探索CTS-SA/CNC多层纳米包装对鲜切雪梨呼吸代谢的影响。在4℃贮藏条件下,通过定期分析鲜切雪梨的呼吸强度、褐变度、还原糖含量和呼吸代谢相关酶活性,发现经CTS-SA/CNC包装的鲜切雪梨在贮藏第7天的褐变度为23.4±1.6,呼吸强度为(19.9±1.3)CO_(2)·mg/(kg·h),均明显低于对照组。此外,相较于对照组,CTS-SA/CNC包装组的糖酵解途径中丙酮酸激酶和磷酸丙糖异构酶的活性提高至(84.4±11.5)U/g和(412.6±9.8)nmol/(min·g),三羧酸循环中丙酮酸脱氢酶和琥珀酸脱氢酶的活性提升至(162.7±14.7)U/g和(20.7±3.4)U/g,磷酸戊糖途径中葡萄糖6-磷酸脱氢酶和6-磷酸葡糖酸脱氢酶的活性提高至(102.9±6.6)U/g。综合考虑各指标的变化,使用CTS-SA/CNC多层纳米膜对鲜切雪梨进行包装贮藏可以有效抑制其呼吸作用,保持生理品质,延长货架期。

In this study,a multilayer nanocomposite film composed of chitosan(CTS),sodium alginate(SA),and cellulose nanocrystals(CNC)was utilized for packaging fresh-cut Pyrus nivalis,aiming to investigate the impact of CTS-SA/CNC nanocomposite packaging on the respiratory metabolism of thePyrus nivalis.Under storage conditions of 4℃,the respiratory intensity,browning index,reducing sugar content and respiratory metabolism-related enzyme activities of the fresh-cut Pyrus nivalis were regularly analyzed.It was observed that on the 7th day of storage,the browning index was significantly lower at 23.4±1.6 and the respiratory intensity was significantly reduced at(19.9±1.3)CO_(2)·mg/(kg·h)in the Pyrus nivalis packaged with CTS-SA/CNC compared to the control group.Additionally,compared to the control group,the CTS-SA/CNC packaging group exhibited increased activities of pyruvate kinase and triose-phosphateisomerase in the glycolysis pathway,with levels reaching(84.4±11.5)U/g and(412.6±9.8)nmol/(min·g),respectively.Furthermore,activities of pyruvate dehydrogenase and succinate dehydrogenase in the tricarboxylic acid cycle were elevated to(162.7±14.7)U/g and(20.7±3.44)U/g,respectively.Moreover,activities of glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase in the pentose phosphate pathway were enhanced to(102.9±6.6)U/g,respectively.Taking into account the changes in various indicators,the use of CTS-SA/CNC multilayer nanocomposite film for packaging and storage of freshly cut Pyrus nivalis effectively suppressed their respiratory activity,preserved their physiological quality,and extended their shelf life.