Abstract: The effects of high-temperature heating, repeated freezing and thawing, and ultraviolet (UV) irradiation on the acceleration of lipid oxidation in pork backfat were compared. Changes in the acid value (AV), free fatty acid (FFA) content and composition, peroxide value (POV), thiobarbituric acid reactive substances (TBARS) value, lipid oxidation products (LOP) and microbial load of pig backfat were measured to obtain the most suitable accelerated lipid oxidation method. The results showed that high-temperature heating treatment was the most effective way to promote lipid oxidation, increasing the POV from (0.008 3 ± 0.00) to (0.053 0 ± 0.00) g/100 g and the TBARS value from (0.24 ± 0.01) to (0.65 ± 0.00) mg/kg. Repeated freezing-thawing treatment increased the POV from (0.018 0 ± 0.00) to (0.034 7 ± 0.00) g/100 g and the TBARS value from (0.13 ± 0.00) to (0.25 ± 0.00) mg/kg, and UV irradiation increased the POV from (0.008 1 ± 0.00) to (0.019 8 ± 0.00) g/100 g and the TBARS value from (0.07 ± 0.00) to (0.21 ± 0.00) mg/kg. No microorganisms were detected in the high-temperature heating treatment. In the repeated freezing-thawing and UV irradiation treatments, the number of microorganisms gradually increased with the number of freezing-thawing cycles or irradiation time. This does not rule out the influence of microbial growth on lipid oxidation. Therefore, high-temperature heating treatment is the most suitable method to accelerate lipid oxidation among these three methods.

Key words: high-temperature heating treatment; repeated freezing-thawing treatment; ultraviolet irradiation treatment; lipid oxidation; number of microorganisms