Preparation, characterization and pork preservation of antibacterial chitosan composite film based on ethyl p-methoxycinnamate isolated from Kaempferia galanga L.

Abstract

Chitosan (CS)-based films incorporated with ethyl p-methoxycinnamate (EPMC) isolated from Kaempferia galanga L. were fabricated to prolong the shelf life of refrigerated pork. Addition of EPMC into CS-based films significantly improved the physical properties, such as opacity (6.42 to 46.33), moisture content (44.01% to 33.29%) and water vapor permeation (0.21 to 0.13 g mm kPa⁻¹ h⁻¹ m⁻²). These changes were verified via multiple spectral techniques, indicating that the improvement in the characteristics of the composite films probably resulted from the intermolecular interaction between CS and EPMC. The diameter of the inhibition zone against Escherichia coli of the composite film with a high content (0.4%) of EPMC increased from 1.42 cm in the control CS group to 1.93 cm. The pH values, thiobarbituric acid-reactive substances, total volatile base nitrogen and total viable count of bacteria of fresh pork stored at 4 °C for 8 days coated in composite film with a high content (0.4%) of EPMC were 5.8, 0.66 mg kg⁻¹, 20 mg (100 g)⁻¹ and 10⁶ CFU g⁻¹, respectively. This indicates that shelf life of fresh pork coated in the composite film was prolonged up to 8 days at 4 °C. The results demonstrated the considerable potential for the utilization of the composite film in pork preservation. © 2024 Society of Chemical Industry.