Maintaining fruit quality and reducing waste: A pectin-rosemary nano-emulsion coating for apple and banana preservation

Edible coatings remain an alternative to modifying the atmosphere and low-temperature storage for fruit preservation and utilization. In this context, this study investigated the pectin, essential oil nano-emulsion, and glycerol composite coating solution to preserve bananas and apples. Pectin and essential oil are extracted from lemon peel and Rosmarinus officinalis (rosemary) leaf. GC–MS analysis showed that the rosemary leaf essential oil consists mainly of bioactive compounds such as 1,8-cineole, mentha camphor, and ferruginol. The Design-expert software was employed and optimized the composite coating formulation (high desirability of 0.945) with a pectin solution of 72.5 ml, rosemary essential oil nano-emulsion of 24.4 ml, and glycerol of 3.1 ml, resulting in higher transparency (88.95 %), the lowest water holding capacity (19.19 g/100 g), and higher tensile strength (15.74 MPa). Apples and bananas were coated with the optimal edible coating solution, and nutritional quality and microbiological analysis were evaluated up to 25 days of storage at room temperature. The study assessed the food quality parameters of coated fruits during storage, which range from proteins (3.57±0.02 g to 1.28±0.01 g), fat (0.38±0.01 g to 0.13±0.01 g), carbohydrates (13.26±0.03 g to 11.12±0.02 g), and vitamin A (177.5 ± 0.43 to 152.63±0.28 mg in coated bananas and 55.81±0.36 to 38.93±0.63 mg in coated apples). Also, compared to uncoated controls, the coated fruits exhibited reduced microbial decay and significantly less weight loss up to 25 days. Thus, this study concludes that the pectin-rosemary essential oil nano-emulsion-glycerol composite edible coating can aid in preserving apples and bananas and other fruit and vegetables for extended periods.