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BACKGROUND: Food marketers desire residue‐free fresh grapes although grapes have a short postharvest life. This study was performed to determine the influences of pre‐ and/or postharvest chitosan (Ch) coatings on postharvest quality of minimally processed (stem‐detached) organic 'Crimson Seedless' berries. Berries were sorted as: (a) control (untreated berries); (b) preharvest Ch (dipping the clusters on the vine into 1% Ch 10 days before harvest at 20% soluble solid content (SSC)); (c) postharvest Ch (dipping the stem‐detached berries into 1% Ch); and (d) pre + postharvest Ch. Berries were stored in 12 × 15 cm rigid polypropylene cups for up to 42 days at 1.0 ± 0.5 °C. RESULTS: Pre‐ and/or postharvest Ch coating reduced weight loss during storage. Pre‐ + postharvest Ch was the best treatment for restricting polygalacturonase (PG) activity, extending the visual quality, color features (L*, C and h°), skin rupture force, biochemical (SSC, titratable acidity, maturity index and pH) and bioactive (total phenol content, antioxidant activity) features. Pre‐ or postharvest Ch was also significantly effective in maintaining many quality features. CONCLUSION: Pre‐ and/or postharvest 1% Ch coatings effectively maintained the quality of minimally processed grape berries of organically produced 'Crimson Seedless' grapes by delaying weight loss and PG activity and keeping the postharvest physical, biochemical and bioactive features for 42‐day cold storage at 1.0 ± 0.5 °C. The combined use of pre‐ and postharvest Ch found to be more effective than single treatment. Thus, pre‐ + postharvest 1% Ch coating could be recommended as an ecofriendly sustainable methodology for extending the postharvest quality of minimally processed fresh grapes. © 2024 The Author(s). Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

International trade in table grapes has expanded tremendously over the last few decades, with out-of season fresh produce now being consumed and traded globally. However, fresh table grapes decay quickly due to pathogen infestation and water loss, which make it difficult to preserve without an effective treatment. The objective of this study was to determine the effects of UV‑C and chitosan coatings (1%), alone or in combination, on the quality of minimally processed table grapes cv 'Michele Palieri' during cold storage at 1 ± 0.5 °C and 90 ± 5% RH for 21 days. The minimal operation was performed by cutting the pedicel with a sharp scissor leaving 1–2 mm of cap stem. The treatments were effective on maintenance of general quality of the berries in comparison to control. But, the chitosan coating with UV‑C irradiation could further extent the postharvest quality of stem-excised 'Michele Palieri' berries, by restraining the increase in weight loss and keeping the visual quality compared to other treatments. Overall results showed that UV‑C plus chitosan treatment can be an effective method for enhancing the phytochemical content and delaying the senescence of minimally processed table grapes during cold storage. [ABSTRACT FROM AUTHOR]

Certain postharvest disorders such as rachis desiccation, weight loss, accelerated softening and biochemical changes limit the postharvest life of table grapes. The present study was conducted to evaluate the effect of pre-harvest micronized calcium pulverizations, postharvest UV-C treatment and their combined applications on extending postharvest quality of table grapes cv 'Crimson Seedless'. Pre-harvest micronized calcium pulverization was performed to improve rachis greenness and berry resistance while postharvest UV-C was aimed to induce physiological resistance and delay senescence in grape berries. Ca treatments significantly increased chlorophyll concentrations of rachis while Ca plus UV-C was the best treatment to maintain rachis chlorophyll concentration. UV-C with or without pre-harvest Ca treatment effectively delayed the weight loss during the storage. Ca delayed the increase of SSC during the storage. All the treatments, particularly postharvest UV-C, significantly delayed the berry senescence by delaying the decrease in acidity. UV-C with or without Ca, with the lowest values, significantly retarded the changes in phenols and decreased the berry decay. Ca plus UV-C treatment also effectively maintained the skin rupture force during the storage. Overall, pre-harvest micronized Ca pulverizations plus postharvest UV-C treatment can be recommended to extent the quality of table grapes cv. 'Crimson Seedless' up to 120 days at cold storage. [ABSTRACT FROM AUTHOR]

Demand for fresh grapes is increasing globally due to their rich composition in phenolic compounds, which have a strong antioxidant capacity. However, fresh table grapes deteriorate rapidly due to berry water loss and pathogen growth, which make it difficult to preserve without treatment. Chitosan coating, as a healthy, simple and innovative technology against to common SO2 fumigation, was tested at various concentrations (0%, 0.5%, 1.0% and 2.0%) for the effectiveness on postharvest quality extension of detached grapes of 'Alphonse Lavallée' cultivar. Chitosan coating at all doses significantly retarded the loss in berry weight, extended the skin rupture force and total phenol content. Visual quality was higher due to coating the berries with chitosan. Chitosan at all concentrations was effective on delaying maturity index (used to express postharvest senescence) and changes in berry colour values such as L*, C and Hue angle. Among the applied doses, 1% chitosan solution can be recommended to apply since higher doses were more effective with similar results on overall quality features of berries. Overall findings demonstrated that chitosan as an edible coating with their unique barrier can be utilized as a natural preservative of detached grapes to extend the postharvest quality up to 28 days. [ABSTRACT FROM AUTHOR]