Propyl Gallate Treatment Improves the Postharvest Quality of Winter Jujube (Zizyphus jujuba Mill. cv. Dongzao) by Regulating Antioxidant Metabolism and Maintaining the Structure of Peel

Zhaohui Xue,Caie Wu,Cunkun Chen,Xiaohong Kou,Xiaoyang Zhao,Chao Wang

doi:10.3390/foods11020237

Zhaohui Xue, Caie Wu + Show 4 more

Open Access

https://doi.org/10.3390/foods11020237

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Abstract

The quality and color of winter jujube fruits are easy to change after harvest. We studied the regulation mechanism of propyl gallate (PG) on post-harvest physiological quality of winter jujube, from the perspective of antioxidant metabolism and peel structure. In our research, winter jujube fruits were treated with 0.001 mol L−1 PG solution for 20 min. Our results showed that PG delayed the development of peel color, and improved the firmness, total soluble solids (TSS), and titratable acid (TA) of winter jujube. Meanwhile, the PG treatment had higher content of total phenols, total flavonoids, ascorbic acid (AsA), and reduced glutathione (GSH), and kept the enzyme activity including superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and peroxidase (POD) at a higher level. PG treatment reduced membrane oxidative damage and maintained the integrity of pericarp structure by reducing electrolyte leakage (EL), lipoxygenase activity (LOX), hydrogen peroxide (H2O2), and malondialdehyde (MDA) content in the peel. Accordingly, PG improved the postharvest quality of jujube fruits by regulating antioxidant metabolism and maintaining the structure of peel. The appropriate concentration of PG has good application potential in the storage and preservation of fresh fruits such as winter jujube.

Highlights

The visual appearance of winter jujube fruits in both groups almost remained unchanged in the initial fifteen days of storage (Figure 1), but the peel of the control turned red from Day 30, 15 d earlier than that of propyl gallate (PG) treatment
PG treatment significantly delayed the development of pericarp color of winter jujube during the storage period, compared with the control
The F values of treatments for all variables were higher than the F values of storage time, except the reddening index, firmness, total soluble solids (TSS), electrolyte leakage (EL), and total phenol, which indicated that the effect of treatments on postharvest quality of winter jujube was more significant than the storage times

Summary

Introduction

China and is a famous fresh fruit. It is delicious and juicy, with thin and crisp peel, and rich in dietary fiber, amino acids, vitamin C, and minerals [1]. They are popular among consumers and have good market prospects. Winter jujubes are prone to water loss, discoloration, softening, and loss of freshness during transportation, storage, and marketing, resulting in a rapid decrease in edible quality and nutritional value of the fruit [2,3]. How to keep the freshness of winter jujube fruits after harvest is an urgent problem to be solved during the industrialization of winter jujube

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