Developing sodium alginate based edible film incorporated with potassium sorbate and application for fresh cold pork preservation

Abstract

Cold-stored fresh pork is widely consumed worldwide, whereas quality deterioration and spoilage limit its shelf-life and commercial value. The present study aims to develop a sodium alginate-based edible film incorporated with varying concentrations of potassium sorbate (PS) ranging from 0% to 5%, using 4% glycerol as a plasticizer. The optimal concentration of PS was determined to be 3% based on a comprehensive characterization of the film's optical, mechanical, and antimicrobial properties. The edible film containing 3% PS in a 2% sodium alginate substrate exhibited a uniform surface and well-arranged microstructure, with the film thickness of 0.43 mm, tensile strength (TS) of 7.11 MPa, elongation at break (EB) of 75.5%, and Water vapor permeability (WVP) of 1.33 g‧mm‧m⁻²‧h⁻¹‧kPa⁻¹. This formulation demonstrated superior tensile strength, elongation at break, and appropriate water vapor permeability. The preservation efficacy of the developed PS edible film on fresh pork was evaluated in comparison to PS solution spraying and dipping approaches. The results indicated that the PS edible film most effectively maintained the appearance, sensory attributes, and physiological quality of fresh pork during cold storage at 4 °C for 14 d. On the 14 d, the total volatile basic nitrogen (TVB-N) content was as low as 2.38 mg‧100 g⁻¹, the thiobarbituric acid reactive substances (TBARS) content was 0.63 mg‧kg⁻¹, the total viable count (TVC) was 5.12 log cfu‧g⁻¹, and the total count of molds and yeasts was 5.05 log cfu‧g⁻¹, which were significantly lower than those observed in the spraying and dipping treatments. These findings support the use of the PS edible film as an effective antimicrobial packaging solution, offering significant potential for preserving the quality of cold-stored fresh pork and extending its shelf life.