Advances in the Understanding of Postharvest Physiological Changes and the Storage and Preservation of Pitaya.

Highly prized for its unique taste and appearance, pitaya is a tasty, low-calorie fruit. It has a high-water content, a high metabolism, and a high susceptibility to pathogens, resulting in an irreversible process of tissue degeneration or quality degradation and eventual loss of commercial value, leading to economic loss. High quality fruits are a key guarantee for the healthy development of economic advantages. However, the understanding of postharvest conservation technology and the regulation of maturation, and senescence of pitaya are lacking. To better understand the means of postharvest storage of pitaya, extend the shelf life of pitaya fruit and prospect the postharvest storage technology, this paper analyzes and compares the postharvest quality changes of pitaya fruit, preservation technology, and senescence regulation mechanisms. This study provides research directions for the development of postharvest storage and preservation technology.

Thymol application delays the decline of fruit quality in blueberries via regulation of cell wall, energy and membrane lipid metabolism.

In this study, we evaluated the potential for exogenous thymol to slow this decline by measuring the effects of thymol application on cell wall, energy, and membrane lipid metabolism. The results showed that thymol application improved the preservation of the total soluble solids, titratable acidity, decay rate, and anthocyanin content, and effectively inhibited the accumulation of O2·-, H2O2, and malondialdehyde in blueberries during storage. Thymol application also effectively maintained fruit firmness, cell wall structure, and energy levels, while delaying the degradation of membrane phospholipids and unsaturated fatty acids during the storage of post-harvest blueberries. Therefore, exogenous thymol can maintain the quality of blueberry fruits by regulating energy and membrane lipid metabolism and reducing cell wall degradation. Thus, thymol-treatment could be a suitable biocontrol agent for maintaining blueberry quality and extending blueberry fruit storage life.

Maintaining quality of postharvest green pepper fruit using melatonin by regulating membrane lipid metabolism and enhancing antioxidant capacity.

Green pepper quality often deteriorates during storage because of membrane lipid damage and oxidative stress. This study investigated the effects of exogenous melatonin (MT) on green pepper storage quality, membrane lipids, and antioxidant metabolism. The results showed that MT increased the activities of superoxide dismutase, catalase, ascorbate peroxidase, peroxidase, monodehydroascorbate reductase, and dehydroascorbate reductase in green peppers compared to the control group. It upregulated expression of multiple enzymes; reduced accumulation of reactive oxygen species such as dehydroascorbic acid, H2O2, and O2.-; and maintained high ascorbic acid, glutathione, coenzyme II, and nicotinamide adenine dinucleotide while reducing oxidized glutathione levels. In addition, MT decreased lipoxygenase and phospholipase D activities, downregulated ReLOX and RePLD expression, and delayed the degradation of phosphatidylcholine, phosphatidylethanolamine, and oleic, linoleic, and linolenic acids in green peppers. These results suggest that MT helps to improve the chilling injury and quality of green peppers and extends shelf life.