| Satsuma mandarins may cause to overstock even rot due to the physiologicaldisorder of the organization or aging during the postharvest storage and transportationprocess, resulting in huge economic losses, which is the important issue of the citrusindustry to study and resolve urgently. Preserving fresh-keeping techniques ordeveloping new biological preservative is the main way to solve this problem.Sucrose-based polymers(SBP) is a biodegradable, non-toxic, environmentally friendlyand water-soluble new fresh-keeping coating agent which can significantly improvethe qualities of fruits and vegetables during storage. This study was to research andthe effects of SBP coating treatments with varying concentrations (0.1%,0.2%,0.3%,0.5%and1.0%, v/v) on postharvest fruit quality of Satsuma mandarin (Citrus unshiuMarc. cv. Miyagawa Wase). The present study used SBP treatments to coat‘Miyagawa Wase’ fruits and then stored at room temperature and low temperature(4℃) conditions. We measured decay rate, soluble solids concentrations, titratableacidity(TA), total sugars, vitamin C(Vc) and total carotenoids, the activity of catalase(CAT), superoxidase dismutase (SOD), polyphenol oxidase (PPO) and theperoxidase(POD) of ‘Miyagawa Wase’ during the period of25days. In addition, wealso illustrated the effects of0.3%SBP on soluble sugar and organic acid of theprecocious ‘Miyagawa Wase’.The results showed that the titratable acidity contents of ‘Miyagawa Wase’ fruitstreated by SBP were significantly lower than the control (p <0.05) under roomtemperature conditions. Vc contents, total sugar contents and soluble solids contentswere higher than the controls (p <0.05).0.2%and0.3%SBP had the most significantdifferences of total sugars contents compared to the controls. The total carotenoidscontents in treated peel and pulp were also higher than the controls. In addition, SBPcould also significantly improve the activities of antioxidant enzymes (CAT, SOD andPOD) of ‘Miyagawa Wase’ fruit. SBP could restraint the activity of PPO of treatedfruits and the changes of the fruits after treated with0.3%and1.0%SBP were mostsignificant.SBP could also significantly improve the quality of ‘Miyagawa Wase’ fruitsunder low temperature conditions. It could increase the soluble solids concentrations,Vc, total sugars and total carotenoid contents, the activities of CAT and SOD, whilethe decay rate, TA, the activity of PPO were greatly reduced. The titratable acid contents of0.3%SBP treated fruits were lower than the controls throughout the wholestorage period, and its Vc content reached to19.74mg/100g, higher than the controland treated fruits with other concentrations on15d; The activities of POD of treatedfruits had the maximum differences compared with the controls after10d.SBP could significantly increase the contents of soluble sugar in the pulp of theprecocious ‘Miyagawa Wase’ in the early and late storage period. The total sugar,glucose and fructose had the same changing trends, however, this difference was notsignificant in the peel; SBP could significantly reduce the organic acid contents ofprecocious ‘Miyagawa Wase’, especially the citric acid.The research results suggested that SBP not only improved the fruit quality of‘Miyagawa Wase’, but also delayed the aging and extended the shelf life of thiscultivar. Our present study provided the theoretical data for the practical application ofthe SBP on the area of the fruits and vegetables fresh-keeping. It could also play asignificant guidence role in improving the economic value of citrus processing waste. |
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