•Wax profile in blueberry fruits were determined using GC–MS and SEM.•Two β-diketones were detected in the blueberry wax for the first time.•Ursolic or oleanolic acid was the most abundant ...triterpenoids.•Tube-type waxes were found in the fruits of all the examined cultivars.
The chemical composition and morphology of cuticular wax in mature fruit of nine blueberry cultivars were investigated using gas chromatography–mass spectrometry (GC–MS) and scanning electron microscope (SEM). Triterpenoids and β-diketones were the most prominent compounds, accounting for on average 64.2% and 16.4% of the total wax, respectively. Ursolic or oleanolic acid was identified as the most abundant triterpenoids differing in cultivars. Two β-diketones, hentriacontan-10,12-dione and tritriacontan-12,14-dione, were detected in cuticular wax of blueberry fruits for the first time. Notably, hentriacontan-10,12-dione and tritriacontan-12,14-dione were only detected in highbush (V. corymbosum) and rabbiteye (V. ashei) blueberries, respectively. The results of SEM showed that a large amount of tubular wax deposited on the surface of blueberry fruits. There was no apparent difference in wax morphology among the nine cultivars.
•UV-C treatment delayed senescence in postharvest peach fruit.•UV-C decreased respiratory activity by inhibiting SDH and CCO activities.•UV-C treated fruit manifested better integrity of ...mitochondrial membrane.•Decreased respiratory activity by UV-C was attributed to senescence retardation.•The delay of senescence by UV-C was also due to the increased mitochondrial membrane integrity.
The effect of 3.0kJ/m2 ultraviolet-C (UV-C) treatment on respiratory activity and mitochondrial membrane associated with fruit senescence in peach fruit stored at 20°C for 8days was investigated. UV-C treatment could reduce senescence development, as evidenced by higher fruit firmness due to inhibition of respiration rate via reducing succinic dehydrogenase and cytochrome C oxidase activity. Meanwhile, the activities of superoxide dismutase, catalase and ascorbate peroxidase in the UV-C-treated fruit were much higher than those in control fruit, resulting in lower levels of superoxide radicals (O2−) and hydrogen peroxide (H2O2). In addition, this treatment maintained a higher level of mitochondrial membrane fluidity and inhibited opening of mitochondrial permeability transition pore. Our results suggest that the induction of antioxidant enzymes to scavenge O2− and H2O2 by UV-C treatment was associated with the maintenance of mitochondrial membrane integrity, which also played an important role in senescence retardation in peach fruit.
► The levels of proline and GABA increased during the chilling development in loquat fruit. ► MeJA regulated enzymes involved in proline and GABA metabolism in loquat fruit. ► MeJA alleviated ...chilling in loquat fruit due to the increased proline and GABA partly.
Loquat fruit were pretreated with 10μmoll−1 methyl jasmonate (MeJA) for 24h at 20°C and then stored at 1°C for 35days to investigate the effect of MeJA treatment on chilling injury (CI) and changes in the contents of proline and γ-aminobutyric acid (GABA). The control fruit exhibited severe flesh leatheriness, a specific CI symptom, after 21days of storage at 1°C, but it was reduced in MeJA-treated fruit. During the development of CI in fruit, proline and GABA accumulated with the storage time, while MeJA treatment enhanced the increases in proline and GABA contents. The MeJA-treated fruit exhibited higher activities of Δ1-pyrroline-5-carboxylate synthetase (P5CS), ornithine δ-aminotransferase (OAT) and glutamate decarboxylase (GAD), and lower proline dehydrogenase (PDH) activity than control during storage. These results suggest that the reduction in CI in loquat fruit by MeJA may be due to the increased proline and GABA contents.
Blue light irradiation was applied to postharvest strawberry fruit to explore its influence on anthocyanin content and anthocyanin biosynthetic enzyme activities. Strawberry fruit was irradiated with ...blue light at 40 μmol m–2 s–1 for 12 days at 5 °C. The results indicated that blue light treatment improved total anthocyanin content in strawberry fruit during storage. Meanwhile, the treatment increased the activities of glucose-6-phosphate, shikimate dehydrogenase, tyrosine ammonia-lyase, phenylalanine ammonia-lyase, cinnamate-4-hydroxylase, 4-coumarate/coenzyme A ligase, dihydroflavonol-4-reductase, chalcone synthase, flavanone-3-β-hydroxylase, anthocyanin synthase, and UDP-glycose flavonoid-3-O-glycosyltranferase, which suggested that the enhancement of anthocyanin concentration by blue light might result from the activation of its related enzymes. Blue light might be proposed as a supplemental light source in the storage of strawberry fruit to improve its anthocyanin content.
Loquat fruit were pre-treated with 10
μmol/l methyl jasmonate (MeJA) for 24
h at 20
°C, and then stored at 1
°C for 35
days to investigate the effect of MeJA treatment on chilling injury and changes ...in the antioxidant system. Loquat fruit developed chilling injury, manifested as increased fruit firmness, decreased extractable juice rate and internal browning during storage. These chilling injury symptoms were significantly reduced by MeJA treatment. MeJA also markedly delayed the increases in O
2
−
production rate and H
2O
2 content. Meanwhile, the MeJA-treated fruit exhibited significantly higher activities of superoxide dismutase, catalase and ascorbate peroxidase, and lower activity in lipoxygenase than control fruit during the storage. The ratio of unsaturated/saturated fatty acid in MeJA-treated fruit was also significantly higher than that in control fruit. These results suggest that the reduction in chilling injury by MeJA may be due to enhanced antioxidant enzyme activity and higher unsaturated/saturated fatty acid ratio.
The effect of exogenous γ-aminobutyric acid (GABA) on chilling injury of peach fruit was investigated. Freshly harvested peaches were treated with 1, 5, or 10 mM GABA at 20 °C for 10 min and then ...stored at 1 °C for up to 5 weeks. The results showed that all of the GABA treatments could reduce chilling injury of peach fruit with 5 mM being the most effective concentration. GABA treatment significantly enhanced the accumulation of endogenous GABA and proline, which resulted from the increased activities of glutamate decarboxylase, Δ1-pyrroline-5-carboxylate synthetase, and ornithine δ-aminotransferase and decreased proline dehydrogenase activity. Our results revealed that GABA treatment may be a useful technique to alleviate chilling injury in cold-stored peach fruit, and the reduction in chilling by GABA may be due to the induction of endogenous GABA and proline accumulation. These data are the first evidence that exogenous GABA induced chilling tolerance in postharvest horticultural products.
► Chilling resistance of loquat fruit differed from the cultivars. ► ‘Qingzhong’ fruit manifested higher membrane lipid unsaturation. ► The resistant cultivar showed higher activities of antioxidant ...enzymes. ► Loquat chilling resistance was due to lipid unsaturation and antioxidant system.
Two cultivars of loquat fruit with contrasting chilling resistance were stored at 1
°C for 35
days to investigate the relationship between chilling injury and fatty acid composition and its antioxidant system. No symptoms of chilling injury occurred in the fruit of ‘Qingzhong’ cultivar during the whole storage, whereas in ‘Fuyang’ fruit, chilling injury increased sharply after 21
days of storage at 1
°C. ‘Qingzhong’ fruit had lower levels of superoxide radical and H
2O
2, in addition to lower lipoxygenase activity, but higher membrane lipid unsaturation and higher activities of superoxide dismutase and catalase than ‘Fuyang’. Furthermore, the chilling resistant ‘Qingzhong’ fruit also showed higher activities of antioxidant enzymes involved in ascorbate–glutathione cycle and higher levels of ascorbate acid and reduced glutathione. These results suggest that the higher membrane lipid unsaturation and the more efficient antioxidant system were both beneficial in enhancing resistance of loquat fruit to chilling injury.
► GABA treatment inhibited chilling injury development in cold-stored peach fruit. ► GABA treatment induced higher activities of antioxidant enzymes. ► GABA-treated fruit showed higher ATP content ...and energy charge. ► Chilling tolerance was induced by GABA in peaches, due to increased ATP content and antioxidant system.
Peach fruit were immersed in 5mM γ-aminobutyric acid (GABA) solution for 10min at 20°C and then stored at 1°C for 5weeks to investigate the effect of GABA treatment on chilling injury (CI), antioxidant enzymes and energy status in peach fruit. The results showed that GABA treatment significantly inhibited CI incidence of peaches and enhanced activities of antioxidant enzymes, such as superoxide dismutase, catalase, ascorbate peroxidase, glutathione peroxidase, glutathione S-transferase, monodehydroascorbate reductase and dehydroascorbate reductase. The treatment also increased contents of adenosine triphosphate and adenosine diphosphate, but lowered adenosine monophosphate content, which resulted in a higher level of energy charge in treated fruit. These results indicated that GABA increased chilling tolerance of peach fruit through enhancing its enzymatic antioxidant system and maintaining energy status in peach fruit.
•Cooking methods affect the nutritional quality of red cabbage.•Fresh-cut red cabbage could retain the highest nutrition.•Steaming with less water and cooking time was recommended to use in Asian ...cuisine.
The aim of this work is to investigate the effects of domestic cooking methods, including steaming, microwave heating, boiling and stir-frying on the nutritional quality of red cabbage. Compared with fresh-cut red cabbage, all cooking methods were found to cause significant reduction in anthocyanin and total glucosinolates contents. Moreover, steaming resulted in significantly greater retention of vitamin C and DPPH radical-scavenging activity, while stir-frying and boiling, two popular Chinese cooking methods, led to significant losses of total phenolic, vitamin C, DPPH radical-scavenging activity, and total soluble sugar as well as reducing sugars. Normally, red cabbage consumed fresh in salads could maintain the highest nutrition. However, considering the habits of Asian cuisine, it is recommended to use less water and less cooking time, such as steaming based on our present results, so as to retain the optimum benefits of the health-promoting compounds.
The influence of high O2 atmosphere on postharvest decay, quality, total phenolic, total anthocyanin contents, antioxidant enzymes activity, and antioxidant activity of Chinese bayberry fruit was ...investigated. Freshly harvested Chinese bayberry fruits were placed in jars and ventilated continuously with air or with 80 and 100% O2 for up to 12 days. Samples were randomly selected initially and at 3-days interval during storage. The fruit exposed to high O2 was resistant to decay, had high levels of total soluble solids, titratable acidity and ascorbic acid contents, and also reduced the increment of pH value. High O2 treatment was less stressful as reflected by having the significantly lower malonaldehyde contents and higher catalase, ascorbic acid peroxidase, and peroxidase activities during storage. Both 80% and 100% O2 treaments had also retained the bioactive contents and 1,1-diphenyl-2-picrylhydrazyl radical scavenging activity during storage. These results indicate that elevated O2 levels may improve the ability of the antioxidative defense mechanism in Chinese bayberry and result in a better control of fruit decay.
