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Yeast mannan treatments effectively delayed colour change and firmness decline and inhibited ethylene production in two cultivars of tomato fruit during storage. The yeast mannan treatment maintained the integrity of tomato pericarp cell wall architecture and suppressed the modification of water-soluble and insoluble pectic polysaccharides in the cell wall. A decrease in the neutral sugars, including d -galactose, l -arabinose and l -rhamnose, in water-insoluble pectin and an increase in these sugars in water-soluble pectin were inhibited by yeast mannan. The contents of d -xylose and d -mannose in the hemicellulose fraction were significantly higher in the yeast mannan-treated fruit after storage. The activities of several cell wall-modifying enzymes, including pectinmethylesterase, polygalacturonase and β-galactosidase, were suppressed in fruit treated with yeast mannan during storage. Overall, the yeast mannan-induced delay in the ripening progress of tomato fruit might occur via the strong suppression of ethylene synthesis, causing inhibition of solubilization and depolymerization of cell wall polysaccharides. [ABSTRACT FROM AUTHOR]

Flesh reddening of ‘Friar’ plum ( Prunus salicina Lindl.) fruit developed rapidly during storage at intermediate temperatures of 5 and 15 °C in comparison to flesh turning yellow at 25 °C and almost no colour change at 0 °C. Thus, modifications of phytochemicals and antioxidant activity during flesh reddening were investigated. Anthocyanins accumulated rapidly in reddening flesh tissue and cyanidin-3- O -glucoside was identified as the absolutely predominant individual anthocyanin. Anthocyanins contributed greatly to the antioxidant activity at 5 °C, and especially at 15 °C by combining with non-anthocyanin phenolics, including protocatechuic, syringic, trans - p -coumaric and caffeic acids. Storage at 15 °C impeded the hydrolysis of sucrose to glucose and fructose, while storage at 5 °C maintained sucrose and accumulated fructose. Intermediate temperatures altered organic acid compositions helping to produce reasonable SSC/TA ratios. These results would provide a postharvest approach for fruit to meet the consumer’s demand for diverse tastes and health promoting effects. [ABSTRACT FROM AUTHOR]

Chilling injury (CI) in green pepper fruits during low-temperature storage causes a significant decline in quality. The present study utilized physiological, transcriptomic, and metabolomic analyses to idneitfy the mechanisms by which trypsin mitigates CI in green peppers stored at 4 °C for 8 days, followed by 3 days of shelf life. Results indicated that the trypsin treatment significantly reduced electrolyte leakage and the CI index in peppers, effectively extending their shelf life and preserving postharvest quality. After 4 days of storage, comparative -omic analyses identified 2514 differentially expressed genes (DEGs) and 397 differentially abundant metabolites (DAMs) between trypsin-treated and control peppers. The trypsin treatment induced changes in sugar metabolism, modulating the expression of HK, SUS, INV, and GLGC, which affected the abundance of metabolites such as CDP-glucose and α-D-p-glucose. Trypsin also enhanced carotenoid metabolism, altering the abundance of rhodopinal glucoside, 1′-hydroxyl-γ-carotene glucoside, and farnesyl 1-PP, and influencing the expression of PDS, CRTH, CRTB, and LUT5. Notably, the trypsin treatment activated the mitogen-activated protein kinase (MAPK) pathway that plays an integral role in the signal transduction of abiotic stress. Differential expression of FLS2, ELF18, PTO, PR1, PTI5, WPKY, MEKK1, and MPK6 genes in the MAPK pathway was observed, which was correlated with CI mitigation in green peppers during cold storage. In conclusion, trypsin is an effective treatment for reducing CI in green peppers during cold storage. The present study provides valuable insights into its physiological and molecular impact on green pepper fruit. • Physiological, transcriptomic, and metabolomic analyses were conducted. • Compared to CK, trypsin treatment identified 2514 DEGs and 397 DAMs in green peppers. • The trypsin treatment induced changes in sugar metabolism. • Trypsin enhanced the carotenoid metabolism, resulting in changes in the abundance. • The results showed that MAPK pathway regulated the CI level of green pepper. • In comparison to CK, trypsin treatment delayed chilling injury of green pepper. [ABSTRACT FROM AUTHOR]

The bacterial derived osmolyte ectoine has been shown to stabilize cell structure and function, a property that may help to extend the shelf life of broccoli. The impact of ectoine on broccoli stored for 4 d at 20 °C and 90% relative humidity was investigated. Results indicated that 0.20% ectoine treatment maintained the quality of broccoli, by reducing rate of respiration and ethylene generation, while increasing the levels of total phenolics, flavonoids, TSS, soluble protein, and vitamin C, relative to control. Headspace-gas chromatography–mass spectrometry, transcriptomic and metabolomic analyses revealed that ectoine stabilized aroma components in broccoli by maintaining level of volatile compounds and altered the expression of genes and metabolites associated with sulfur metabolism, as well as fatty acid and amino acid biosynthesis pathways. These findings provide a greater insight into how ectoine preserves the flavor and nutritional quality of broccoli, thus, extending its shelf life. • Ectoine delayed senescence and maintained broccoli quality during storage. • Ectoine treatment stabilized broccoli aroma components. • Ectoine affected metabolism of sulfur, fatty acid, and amino acid in broccoli. [ABSTRACT FROM AUTHOR]

• LED-BVOCs treatment maintained better green in postharvest broccoli during storage. • LED-BVOCs technology maintained the storage quality of postharvest broccoli. • Transcriptome and metabolome profiling revealed several DEGs and DAMs. • LED-BVOCs technology inhibited chlorophyll degradation and carotenoid accumulation. • The yellowing of broccoli has nothing to do with flavonoids. Volatile organic compounds produced by bacteria (BVOCs) have been proven to effect the postharvest metabolism of fruits and vegetables. The quality, color and antioxidant capacity of membrane lipids of broccoli in storage were effectively maintained by fumigation with BVOCs produced by Lysinibacillus fusiformis combined with white light emitting diode (LED) technology. An analysis of the transcriptome and metabolome of broccoli treated with the combined LED-BVOCs technology resulted in the identification of 49 differentially expressed genes (DEGs) and 13 differentially abundant metabolites (DAMs) involved in photosynthesis (32/0 DEGs upregulated/downregulated; 0/0 DAMs with increased/decreased abundance), chlorophyll (7/0; 1/2), carotenoid (5/0; 1/4) and flavonoid (3/3; 3/2) metabolism. The maintenance of green color in harvested broccoli treated by LED-BVOCs was associated with DEGs and DAMs that inhibited chlorophyll degradation and carotenoid accumulation. Our study provides a theoretical basis for understanding the delayed senescence of broccoli during storage using BVOCs-LED technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • 2.5 mg·L−1 ozone micro-nano bubble water was the optimum treatment in parsley. • Ozone micro-nano bubble water decreased five volatile signatures. • 24 major volatiles and 365 differential metabolites were identified. • Most metabolites related to flavor metabolism were induced. The production and use of ozone micro-nano bubble water (O 3 -MNBW) is an innovative technology that prolongs the reactivity of aqueous-phase ozone and maintains the freshness and quality of fruits and vegetables by removing pesticides, mycotoxins, and other contaminants. The quality of parsley treated with different concentrations of O 3 -MNBW was investigated during storage at 20 ℃ for 5 d, and found that a ten-minute exposure of parsley to 2.5 mg·L−1 O 3 -MNBW effectively preserved the sensory quality of parsley, and resulted in lower weight loss, respiration rate, ethylene production, MDA levels, and a higher level of firmness, vitamin C, and chlorophyll content, relative to untreated parsley. The O 3 -MNBW treatment also increased the level of total phenolics and flavonoids, enhanced peroxidase and ascorbate peroxidase activity, and inhibited polyphenol oxidase activity in stored parsley. Five volatile signatures identified using an electronic nose (W1W, sulfur-compounds; W2S, ethanol; W2W, aromatic- and organic- sulfur compounds; W5S, oxynitride; W1S, methane) exhibited a significant decrease in response to the O 3 -MNBW treatment. A total of 24 major volatiles were identified. A metabolomic analysis identified 365 differentially abundant metabolites (DMs). Among them, 30 and 19 DMs were associated with characteristic volatile flavor substance metabolism in O 3 -MNBW and control groups, respectively. The O 3 -MNBW treatment increased the abundance of most DMs related to flavor metabolism and reduced the level of naringin and apigenin. Our results provide insight into the mechanisms that are regulated in response to the exposure of parsley to O 3 -MNBW, and confirmed the potential use of O 3 -MNBW as a preservation technology. [ABSTRACT FROM AUTHOR]

[Display omitted] • Under red LED irradiation, transcriptome analysis of broccoli showed amino acid metabolism. • Red LED irradiation upregulates the expression of genes encoding the shikimate pathway. • Red LED irradiation induced the branched-chain amino acid biosynthesis pathway. • Under red LED irradiation, amino acids that are glucosinolate's precursors were elevated. • Red LED irradiation can postpone broccoli's postharvest senescence. Whole-transcriptomic profiling combined with amino acid analysis were conducted in order to gain a better understanding of global changes in amino acid metabolism induced in broccoli by red LED irradiation. The results showed that the contents of almost all 16 amino acids in postharvest broccoli were maintained under red LED illumination. The red LED irradiation enhanced the anabolism of amino acid, including the biosynthesis of aromatic amino acids by upregulating the genes' expression in the shikimate pathway, as well as by upregulating the genes' expression which encoding biosynthetic enzymes in the branched-chain amino acid biosynthesis pathway. Red LED irradiation induced the expression of genes encoding aspartate aminotransferase, which plays a role in Asp synthesis, aspartate kinase, which functions in aspartate metabolism, and a cytoplasmic aspartate aminotransferase that converts 2-Oxoglutarate into Glu. Genes encoding imidazole glycerol-phosphate synthase and histidinol-phosphatase, which function in the His biosynthesis pathway, were also upregulated. According to our results, red LED irradiation delays broccoli's yellowing and senescence by regulating amino acid metabolism. These results enhance our understanding of the role of amino acid metabolism in the senescence of broccoli and the mechanism of red LED irradiation to alter amino acid metabolism in harvested broccoli. [ABSTRACT FROM AUTHOR]

• Cellular fluids released from the cut stem are the primary cause of browning. • Mass levels of ROS production have an indirect effect on stem browning. • The browning of cellular fluids was mainly related to the PAL activity increased. • The stem browning was related to unsaturated fatty acids content decreased. • A sufficient supply of energy can maintain the activity of antioxidant enzymes. Cellular fluids and latex released from cut cells in the stems of lettuce when it is harvested are the major source of stem browning. In the present study, the browning process of cellular fluids and latex released from romaine and iceberg lettuce stems was investigated. An increase in LOX enzyme and total phenolics also occurs during lettuce stem browning. A decrease in ascorbic acid content, an increase in phenylalanine ammonia lyase and lipoxygenase activity were important factors responsible for the browning. Metabolomic and proteomic analyses indicated that changes in the level of glutathione metabolism, indole alkaloid biosynthesis, oxidative phosphorylation, galactose metabolism were also associated with stem browning. The main causes of stem browning in fresh cut lettuce were comprehensively investigated in the present study and the resulting data provided information that can be used in the study of browning in lettuce and other vegetables during harvest or fresh-cut processing. [ABSTRACT FROM AUTHOR]