Carboxymethyl cellulose coating delays ripening of harvested mango fruits by regulating softening enzymes activities.

The effect of carboxymethyl cellulose [(1%) CMC] was evaluated on mango fruits under storage at 20 ± 1 °C for 20 days. The CMC coating noticeably reduced weight loss and disease incidence. Application of CMC delayed climacteric peak of ethylene and respiration rate with significantly reduced relative ion leakage, malondialdehyde, superoxide anion and hydrogen peroxide content. The treated mangoes showed significantly lower L*, a*, b* and total carotenoids. The CMC treatment reduced the increase in cellulase, pectin methylesterase and polygalacturonase activity that delayed softening of mango fruits. In addition, activities of peroxidase, catalase, ascorbate peroxidase and superoxide dismutase were substantially higher in CMC-treated mango fruits. The treated fruits showed significantly lower soluble solids and higher titratable acidity which thereby reduced the ripening index of mangoes. In conclusion, CMC treatment could be considered a potential pre-storage treatment to delay postharvest ripening and to conserve the eating quality of ambient stored mango fruits.

Combined application of ascorbic and oxalic acids delays postharvest browning of litchi fruits under controlled atmosphere conditions.

The effect of ascorbic acid [AA (40 mmol L-1)] and oxalic acid [OA (2 mmol L-1)] on browning of litchi fruit was investigated under 5% CO2 + 1% O2 controlled atmosphere (CA) and compared with air at 5 ± 1 °C for 28 days. The combined application of AA and OA suppressed browning index, soluble quinones, and activities of polyphenol oxidase and peroxidase under CA compared with control. The combination of CA along with AA + OA reduced weight loss and maintained higher anthocyanins, total phenolics, membrane integrity, ascorbate peroxidase, catalase, glutathione reductase and superoxide dismutase activities compared with control. In addition, AA + OA + CA combination showed markedly lower malondialdehyde, superoxide anion and hydrogen peroxide with substantially higher soluble solids content, ascorbic acid, titratable acidity and sensory quality compared with control. In conclusion, AA + OA combination could be considered appropriate to delay browning and to conserve litchi fruit visual appearance under CA storage conditions.

Effect of gum arabic coating on antioxidative enzyme activities and quality of apricot (Prunus armeniaca L.) fruit during ambient storage.

The effect of gum arabic (GA) coating was studied on apricot fruit at 20 ± 1°C for 8 days. GA coating substantially reduced weight loss, disease incidence, malondialdehyde concentration, and hydrogen peroxide compared to the control. GA coating resulted in significantly higher total phenols, ascorbic acid, and antioxidant activity in contrast to the control. GA coating also suppressed cellulase, pectin methylesterase, and polygalacturonase activity in contrast to the non-coated fruit. In addition, GA-coated apricot fruit had substantially higher catalase, peroxidase, ascorbate peroxidase, and superoxide dismutase enzymes activities in contrast with the control. Similarly, GA coating inhibited soluble solids content increase and inhibited the reduction in titratable acidity in coated fruit. The fruit coated with GA coating also had significantly better sensory and overall eating quality compared to the control apricots. In conclusion, GA could be considered an appropriate edible coating for quality conservation of apricots. PRACTICAL APPLICATIONS: Apricot is a well renowned and nutrients rich fruit. However, apricot has comparatively short shelf life potential due to its susceptibility to rapid senescence and deterioration under ambient conditions. GA is an eco-friendly and biodegradable coating which is considered relatively cheap as compared with other coating types. In our present work, application of gum arabic [GA (10%)] edible coating maintained significantly higher quality of harvested apricot fruit as compared with the control. The outcomes of the present work are of global significance with respect to apricot industry. So, GA coating could be considered an appropriate edible coating for quality conservation of the harvested apricot fruit.