The impact of Pleurotus eryngii on myofibrillar protein: Physicochemical properties and structural alterations in quick-frozen pork patties during freeze-thaw cycles

This study investigated the impact of Pleurotus eryngii (PE) on the oxidative stability and gel characteristics of myofibrillar protein (MP) from pork patties undergoing multiple freeze-thaw (F-T) cycles. Pork patties with PE served as the experimental group, and those without PE as the control group. The results suggested that PE effectively inhibited MP degradation based on the MP function and structure. After 5 F-T cycles, the protein solubility of MP from patties containing 0.5 % PE powder was significantly higher than the control (P < 0.05). Additionally, the inclusion of PE in patties could inhibit the decrease in whiteness and water-holding capacity, the WHC of MP gels in the control group started at 77.05 % and decreased to 48.67 % after 5 F-T cycles. In the experimental group, the WHC started at 83.81 % and decreased to 59.06 % after 5 F-T cycles. Scanning electron microscopy (SEM) images revealed that the freezing and thawing processes disrupted the regular aggregated structure of MP gels. However, MP gel from patties containing PE formed a relatively smoother and denser network after the same F-T cycle. Furthermore, the inclusion of PE inhibited the degradation and structural unfolding of protein. After many F-T cycles, the carbonyl content of MP grew significantly from 1.85 nmol/mg to 11.69 nmol/mg. When 0.5 % of Pleurotus eryngii was added, the carbonyl content increased from 1.72 nmol/mg to 6.67 nmol/mg, the sulfhydryl content in the control and experimental groups decreased from 12.80 nmol/mg and 12.85 nmol/mg to 3.16 nmol/mg and 10.46 nmol/mg, respectively. These findings underscore the significance of PE in maintaining the structural stability of MP and the physicochemical properties of pork patties during F-Tcycles.