The effects of fatty acid composition on lipid oxidation, protein oxidation and color stability in minced pork

The literature review covers different aspects of lipid oxidation and protein oxidation in meat.The mechanism of lipid and protein oxidation, factors influencing lipid oxidation, the consequences of protein oxidation, measurement methods, and the interactions between lipid oxidation, protein oxidation and meat color are introduced. The present thesis was aiming to study the effects of different fatty acid composition on lipid oxidation, protein oxidation and meat color in minced pork stored in modified atmosphere packages (80% O2, 20% CO2) at 5 oC during 12 days of storage. The possible interactions between lipid oxidation, protein oxidation and meat color were also investigated. Minced meat differing in fatty acid composition was prepared by mixing lean minced meat and fat fractions obtained by dry fractionation. Three groups of minced meat were obtained, namely, more saturated, medium saturated and less saturated. Lipid and protein oxidation were measured by determining thiobarbituric acid-reactive substances (TBARS) and free thiol content, respectively. Meat color measurement was performed using the Hunter L*, a*, b* system. The results showed that the less saturated group had higher oxidative stability in relation to lipid and protein oxidation than the more saturated and medium saturated groups, which might result from the balance between the proportion of unsaturated fatty acids and the vitamin E content. This was supported by the finding that the less saturated samples contained more unsaturated fatty acids and vitamin E than those in the more saturated and medium saturated groups. TBARS level was negatively related to free thiol content, indicating the presence of possible interactions between lipid and protein oxidation. Furthermore, a* values were found to be correlated to lipid and protein oxidation, suggesting likely interactions between these factors. However, color values were not influenced by fatty acid composition.