Fraction I of Whey Protein Hydrolysates Improves Lipid Stability and Water Retention in Ground Pork During Freeze–Thaw Cycles

This study investigated the potential of Fraction I (FI, <1 kDa), a peptide fraction derived from whey protein hydrolysates (WPH) exhibiting strong in vitro scavenging activity against DPPH, superoxide, and hydroxyl radicals, to mitigate quality deterioration in ground pork subjected to up to seven freeze-thaw (F-T) cycles. Ground pork samples were supplemented with FI at three concentrations (5%, 10%, and 15%) and analyzed for oxidative and physicochemical changes. Successive F-T cycles markedly promoted lipid oxidation, as indicated by increased peroxide value and thiobarbituric acid reactive substances (TBARS), and overall quality deterioration, evidenced by a rise in acid value and pH along with a decrease in G″. Incorporation of 10% FI effectively inhibited these oxidative reactions and improved the water-holding capacity of ground pork. These results demonstrate that among the tested concentrations, FI at 10% most effectively enhances oxidative stability and maintains water distribution, thereby preserving the quality of ground pork during multiple F-T cycles.