Development of a coating material composed of sodium alginate and kiwifruit seed essential oil to enhance persimmon fruit quality using a novel partial coating technique

Abstract

We developed edible films composed of sodium alginate (SA) and varying concentrations of kiwifruit seed essential oil (KSO) (10 %, 30 %, and 50 % v/w SA) and extensively characterized. Gas chromatography-mass spectrometry/mass spectrometry revealed that cyclotene, valencene, and camphene are the major components of KSO. Film’s physiochemical parameters revealed that KSO increased the solution’s viscosity from 4.8 to 6.0 cp, and the film’s opacity from 4.2 to 10.6 mm^-1, while also enhancing thermal stability and elongation at break. Fourier-transform infrared spectroscopy and scanning electron microscopy confirmed the induction of KSO into SA. Water contact angle, moisture content, and water vapor permeability results indicated that KSO30 was more hydrophobic than control, KSO10 and KSO50, identifying KSO30 the optimal composition. The final treatments to evaluate partial (P) and full (F) coating on persimmon fruits were uncoated (control), SA, and KSO30. Results indicated that KSO30 was effective in reducing the weight loss and maintaining the firmness and respiration rate compared to the control and SA. Although no significant differences in the respiration rate, firmness, color, or TSS were observed between partially and fully coated persimmons, full coating was more effective in retaining weight loss and pH. At the final day of storage, KSO30 had 5.1 % weight loss and a pH of 6.3, while control fruits had 6.8 % weight loss and a pH of 6.1. Therefore, incorporating SA with KSO is a promising coating material for prolonging the shelf-life of persimmon fruit, and partial coating could be a more economical and viable alternative to full coating.