Postharvest Aloe vera Gel Coatings Delay the Physiological Senescence of ‘Alphonse Lavallée’ and ‘Red Globe’ Grapes During Cold Storage as an Alternative to SO2

This study aimed to reveal the effects of different concentrations (0, 5, 10, and 20%) of Aloe vera gel (AV) coating on the quality-related characteristics of table grapes (‘Alphonse Lavallée’ and ‘Red Globe’) during cold storage at 1.0 ± 0.5 °C with 90 ± 5.0% relative humidity for 75 days. Sulphur dioxide (SO2) was also used as a common chemical-based postharvest application to compare the effectiveness of the treatments. During the cold storage, AV treatments were remarkably effective in delaying the loss in fresh weight of grapes with greater effects than both the control and SO2. Postharvest changes in biochemical features such as the soluble solid contents (SSC), titratable acidity (TA), and maturity index (MI) of both grape cultivars were significantly delayed by AV concentrations. Higher concentrations of AV displayed better protection in the physical, biochemical, and visual quality-related properties of the grape cultivars. Considering the general findings, the use of 10% AV treatment could be recommended as a natural, safe, and healthy alternative strategy to chemicals as it provided better conservation of the fresh grapes in long-term cold storage.