Assessment of antimicrobial edible coatings derived from coffee husk pectin and clove oil for extending grapes shelf life

Grapes are rich in phenolic compounds with potent antioxidant properties that mitigate risks associated with cardiovascular and neurodegenerative diseases. However, postharvest storage often leads to microbial infestations, significantly deteriorating fruit quality. This study investigated the effects of two composite edible coatings i.e., Coffee Husk Pectin-Clove Oil (CHP-CO) and Freeze-Dried Coffee Husk Pectin-Clove Oil (FD-CHP-CO) on prolonging the shelf life of grapes. Coated and uncoated grapes were evaluated for their physicochemical (weight loss, colour, pH, total soluble solids and titratable acidity), bioactive compounds (total phenolics and total flavonoids), in vitro antioxidant and antimicrobial properties during 14 d of storage at ambient (RT, 25 ± 1 °C) and cold (4 ± 1 °C) storage conditions. Coated grapes maintained better quality compared to uncoated grapes, with FD-CHP-CO reducing weight loss by up to 76 % at ambient conditions (0.92 ± 0.26 % vs. 3.89 ± 1.63 % in uncoated grapes). The FD-CHP-CO coating also resulted in a significant inhibition zone increase against Staphylococcus aureus MTCC 96 from 11 to 15 mm. Additionally, the coated grapes showed higher retention of bioactive compounds, with total phenolics and total flavonoids retention of 86.9 % and 83.7 %, respectively. These results suggest that CHP-CO and FD-CHP-CO coatings effectively extend the shelf life of grapes, maintaining their quality and safety during storage, and highlight the potential of these coatings in reducing food waste and improving consumer satisfaction.