Effect Of Different Thicknesses Of PE Preservation Bags On The Storage Effect Of Sweet Cherries

A previous study found that coating sweet cherries with a mixture of 5 g/L potassium cinnamate and 5 g/L sodium alginate improved the storage quality and extended the storage life of sweet cherries.In this study,sweet cherries treated with a mixture of 5 g/L potassium cinnamate and 5 g/L sodium alginate were treated with 0.04 mm thick polyethylene（PE）film bags as CK,and 0.07 mm,0.10 mm and 0.11 mm thick PE film bags as T1,T2 and T3,respectively.The results of the study were as follows:The storage quality,oxidative damage,antioxidant defence,cell wall metabolism and sugar metabolism of sweet cherries were measured in order to find the optimum thickness of PE film bags to improve the storage and preservation technology of sweet cherries and extend their storage and preservation period.The results of the study are as follows:（1）Effect of different treatments on the storage quality of sweet cherriesThe T1,T2 and T3 treatments all inhibited the increase in fruit respiration rate to varying degrees,reduced fruit weight loss and decay,maintained fruit hardness,stabilised total soluble solids（TSS）and titratable acid（TA）content,and delayed the decrease in fruit brightness（L*）,colour saturation（C*）and hue angle（H⁰）.Of all the treatments,the T2 treatment performed best,reducing the respiration rate and decay rate of sweet cherries,inhibiting the reduction in hardness,L*,C*and H⁰ values,and maintaining the colour of sweet cherry fruit;at the end of storage,the weight loss rate of the T2 treatment was 0.14%,a reduction of 26.37%and 66.75%compared to the T1 and T3 treatments respectively.（2）Effect of different treatments on the metabolism of reactive oxygen species in sweet cherriesAll treatments improved the metabolism of reactive oxygen species in stored sweet cherries,with the T2 treatment performing best,effectively reducing the content of superoxide anion（O₂^-）,hydrogen peroxide（H₂O₂）and malondialdehyde（MDA）in sweet cherries.The T2 treatment also maintained the phenolic,flavonoid,ascorbic acid（ASA）and reduced glutathione（GSH）contents of sweet cherries,delayed the onset of peak catalase（CAT）and superoxide dismutase（SOD）activities by 10 days and effectively delayed the reduction of CAT,SOD,polyphenol oxidase（PPO）and peroxidase（POD）activities,significantly improving the The antioxidant capacity of sweet cherry was significantly improved.（3）Effect of different treatments on sweet cherry cell wall metabolismT1,T2 and T3 treatments all inhibited the increase of cellulase（CE-Cx）,polygalacturonase（PG）,β-glucosidase（β-Glu）andβ-galactosidase（β-Gal）activities to different degrees during post-harvest sweet cherry storage and preservation;At the end of storage,CE-Cx activity was 2.49%and 5.37%lower,PG activity was 8.03%and 3.25%lower,andβ-Glu activity was 8.94%and 6.25%lower in T2 than in T3.（3）The cell wall metabolism rate of sweet cherry was significantly inhibited by the different treatments,which decreased by8.94%and 6.73%,andβ-Gal activity by 7.16%and 3.50%,respectively.（4）Effect of different treatments on sugar metabolism in sweet cherryAll treatments inhibited the increase in glucose and fructose content of sweet cherry fruit during storage and maintained high sorbitol and sucrose content in sweet cherry fruit;reduced sucrose synthase（SS-C）,sorbitol dehydrogenase（SDH）activity,acid transformase（AI）and neutral transformase（NI）activity and maintained sucrose phosphate synthase（SPS）activity;among all treatments,T2 treatment At the end of storage,the sorbitol and sucrose contents of T2 treatment were 7.15%and 27.66%higher than those of T1 treatment,and 1.92%and 5.40%higher than those of T3 treatment,respectively;and SS-C,SDH,AI and NI activities of T2treatment were the lowest during storage,while SPS activity was the highest,being 23.04%and The T2 treatment inhibited the metabolism of sucrose and sorbitol in stored sweet cherries and delayed the softening of sweet cherry fruits.