| Kiwifruit(Actinidia chinensis)is an important subtropical fruit with high nutritional value,and the market demand of kiwifruit is growing.However,the ripening process of kiwifruit is rapid,and the respiration is strong during storage,which leads to the decrease of fruit firmness and enzyme activity and the decrease of nutrient content.In this paper,the widely used preservative potassium sorbate was combined with lowdensity polyethylene and linear low-density polyethylene to obtain a potassium sorbate compound packaging.Potassium sorbate compound packaging was used to store kiwifruit under ambient conditions(25℃,45%RH).Taking normal packaging,potassium sorbate soaking as controls.To investigate the preservation effect of potassium sorbate compound packaging on kiwifruit,the physiological and chemical indicators related to physiological metabolism were measured,and high-throughput sequencing technology was used to reveal the changes in kiwifruit microbial community structure during storage.The main results of this paper are:1.Potassium sorbate compound packaging was obtained.The potassium sorbate release analysis showed that the 4.5 mg/L potassium sorbate can be detected in packaging after stored at 4°C for 30 d,which suggested that potassium sorbate can exist in the film for a long time.The storage of kiwifruit in potassium sorbate composite packaging can maintain the firmness of kiwifruit,delay the degradation of soluble solid,slow down the degradation of kiwifruit cellulose and pectin,and delay the decline of total phenol content.When stored for 6 days,the firmness of kiwifruit treated with potassium sorbate compound packaging was 273 g,that in normal packaging and potassium sorbate soaking was 202 g and 211 g.During storage,the respiratory rate and weight loss rate of kiwifruit in potassium sorbate compound packaging was lower than unpacked groups.The results of oxidative stress-related enzymes were significantly higher than those of the control group.The inhibitory effect of oxidative adverse factors was better,the reactive oxygen metabolism process of kiwifruit and the degradation of cellulose,pectin and starch were delayed,potassium sorbate compound packaging can maintain the quality of kiwifruit during storage.2.Electronic nose and GC-MS of kiwifruit flavor was determined during storage under different treatments.The changes in ketones,alcohols,ammonia and oxidizing gases during storage were significant;a total of 47 volatile substances were detected.When stored for 12 days,content of the main volatile aroma components of kiwifruit under potassium sorbate compound packaging-aldehydes and esters,were higher than those in the normal packaging and the control.After 12 days’ storage,the sensory evaluation of kiwifruit was carried out.the results showed that kiwifruit with potassium sorbate packaging was moderately soft and hard,with good taste,which indicated that compared with normal packaging,the potassium sorbate compound packaging can effectively maintain the content of volatile components and ensure the stability of kiwifruit flavor during storage.3.16 S r DNA sequencing analysis was conducted on kiwifruit during storage,and the richness and diversity of the microflora of kiwifruit kept changing during storage.A total of 23 major bacteria genera were measured from kiwifruit in potassium sorbate compound packaging and normal packaging.With the extension of storage time,the relative abundance of Methylobacterium was on the rise and the relative abundance of Ralstonia was on the decline.At the end of storage,the relative abundances of Ralstonia,Sphingomonas,Methylobacterium,and Curtobacterium in kiwifruit with potassium sorbate compound packaging were significantly lower than that with the normal packaging and the control,indicating that compared with the normal packaging,the potassium sorbate compound packaging can inhibit the growth of dominant spoilage bacteria,delay the decline of beneficial bacteria,and effectively protect the quality of kiwifruit. |
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