Effects of Different Thawing Methods on Physicochemical Properties and Oxidation Stability of Porcine Liver

To study the effects of thawing methods, including water immersion thawing, ambient temperature thawing, refrigeration thawing, microwave thawing, and ultrasonic thawing, on the physicochemical properties and oxidation stability of porcine liver, the total number of colonies, pH, thawing loss, color, POV value, TBA value, carbonyl content, and sulfhydryl content were investigated. The results showed that the thawing rates were different depending on thawing methods; microwave thawing had the shortest thawing time, whereas refrigeration thawing had the longest thawing time. Microwave thawing controlled the microbe quantity and reduced the thawing loss, but increased the oxidation of lipids and proteins. Refrigeration thawing and ultrasonic thawing had better color and lower oxidation of lipid and protein, while the thawing loss of porcine liver under ultrasonic conditions was higher than that in a refrigerator. The statistical analysis demonstrated that thawing loss had significant correlations to the pH, color, lipid oxidation and protein oxidation (P<0.05), and lipid protein and protein oxidation were highly linked to the color (P<0.05). In addition, we also observed a high correlation between lipid oxidation and protein oxidation (P<0.05). Overall, refrigeration thawing could be more suitable methods for the thawing of porcine liver, and ultrasonic thawing conditions need to be further studied.