Enhanced preservation of postharvest peaches with an edible composite coating solution of chitosan, tannic acid, and beeswax

Abstract

Coating materials play a crucial role in prolonging the shelf life of fruits by establishing a protective barrier against microbial growth and preserving their freshness. In this investigation, we formulated an edible composite coating solution comprising chitosan (CS), tannic acid (TA), and beeswax (BW) in the following proportions: 0.5 % chitosan, 0.5 % tannic acid, and 2 % beeswax. The solution was created by blending equal volumes (1:1) of 1 % CS and 1 % TA solutions. Subsequently, 2 % solid BW was dissolved through gentle heating, with the addition of 0.2 % glycerol and 0.2 % Tween80. This solution exhibited outstanding antioxidant activity, registering a percentage inhibition of 87.64±1.4 %. Moreover, the solution demonstrated antibacterial effectiveness against Escherichia coli and Bacillus subtilis, with an efficiency of 46–48 %, compared to the standard antibiotic Kanamycin. To assess its efficacy in preserving fruits, we applied the solution to peach surfaces using cotton swabs and observed them at room temperature over several days. It became evident that untreated samples began to spoil and exhibited signs of microbial growth within just 3, 4 days, whereas treated samples remained preserved even after 9, 10 days. Additionally, after 6 days, the treated samples showed slightly less weight loss at 9.10±0.63 %, compared to the control samples at 10.31±0.21 %. The fruit firmness of the treated samples was 4.453±0.59 N, while the control samples measured 3.707±1.98 N. The control samples showed a greater decrease in titrable acidity, with a difference of 0.03 % from day 0 to day 9, compared to a difference of 0.024 % in the treated samples. This study underscores the potential of the CS/TA/BW solution as an innovative edible fruit coating, emphasizing its remarkable antioxidant and antibacterial properties.