European Journal of Nutrition & Food Safety

Aims: To develop and evaluate biodegradable polylactic acid (PLA) packaging films incorporated with zinc oxide nanoparticles (ZnONPs) and assess their effects on the physico-chemical characteristics as well as the shelf life of pork chops under frozen condition

Study design:  It is a controlled experiment where different treatments (types of packaging) are applied to the pork chops, and their effects are measured at multiple time points.

Place and Duration of Study: Sample: Department of Livestock Products Technology, College of Veterinary and Animal Sciences, Pookode, Wayanad District, Kerala State, India between June 2024 and December 2024.

Methodology: Plain PLA pouches and PLA pouches incorporated with ZnO were prepared. Pork hind leg chops were used as samples and were procured from a local butcher, cut into 200-250g and then packaged into Low Density Poly Ethylene (LDPE), plain PLA and PLA pouches incorporated with 2.5 per cent and 5 per cent concentrations of ZnO nanoparticles. Samples packed in LDPE were labelled as control while samples packed in PLA, 2.5 per cent PLA/ZnO pouches and 5 per cent PLA/ZnO pouches were labelled as treatment 1 (T1), treatment 2 (T2) and treatment 3 (T3) respectively. All samples were kept under frozen storage (-18 ± 2 ^oC) and analysis was done on the 0^th, 30^th, 60^th, 90^th and 120^th day of storage. The samples were analysed for their physico-chemical properties such as pH, cooking loss, water holding capacity, thiobarbituric acid reactive substances (TBARS) number and tyrosine value. Four trials of the experiment were conducted.

Results: A significant decrease in pH was observed in all the samples across the storage period except in T2 and the water holding capacity of all samples significantly (P ≤0.01) reduced with time. Corresponding to the trend in pH values over storage, was a significant decrease (P<0.01) could be observed in the cooking loss as well as water holding capacity. The TBARS (P<0.01) and tyrosine values P<0.05) increased significantly with time. However, there was no significant difference observed between the samples in any day of analysis indicating that PLA is equally effective as LDPE for the frozen storage of pork. The incorporation of nanoparticles, however did not exert a significant change in the quality of frozen pork.

Conclusion: PLA is equally effective as LDPE as a packaging material for the frozen storage of pork and can offer a sustainable solution to the packaging of muscle foods. The incorporation of nanoparticles, however did not exert a significant change in the quality of frozen pork.