Pork is perishable due to oxidation and microbial spoilage. Edible coating based on biopolymers and phenolic compounds is an effective way to preserve the quality of pork. In this study, ferulic acid-grafted-CS (ferulic acid-g-CS) with strong antioxidant and antimicrobial activities was synthesized through a carbodiimide-mediated coupling reaction. The obtained ferulic acid-g-CS was used as an edible coating material for fresh pork. The effect of ferulic acid-g-CS coating on the quality of pork during storage was investigated at 4 °C for 8 days. As compared to the uncoated pork, pork coated with CS and ferulic acid-g-CS showed lower total viable counts, total volatile basic nitrogen values, pH values, thiobarbituric acid reactive substances, and drip losses. Besides, pork coated with CS and ferulic acid-g-CS presented more compact microstructures than the uncoated pork at the eighth day. Sensory evaluation assay showed pork coated with CS and ferulic acid-g-CS had better color, odor, and over acceptance in comparison with the uncoated pork. Ferulic acid-g-CS coating, due to its relatively higher antioxidant and antimicrobial activities compared to CS coating, had a better performance in refrigerated pork preservation. Ferulic acid-g-CS coating effectively extended the shelf life of refrigerated pork to 7 days. This study revealed ferulic acid-g-CS coating was a promising technology for refrigerated pork preservation.
Keywords: chitosan; edible coating; ferulic acid; graft copolymer; pork preservation.