Effects of in vitro oxidation on myofibrillar protein charge, aggregation, and structural characteristics. (1st December 2020) - Zhang, Dong
Highlights: The stability of myofibrillar protein (MP) solution is affected by many factors. The aggregation effect of MP is greater than the net charge effect in a strong oxidation. Excessive oxidation resulted in the decrease of MP isoelectric point. Excessive oxidation caused serious modification in some basic amino acid. Abstract: The effects of oxidation degree on the isoelectric point (pI), aggregation, and structural characteristics for pork myofibrillar protein (MP) were studied by employing extracted MP, which was incubated by using a hydroxyl radical oxidation system. The concentrations of hydrogen peroxide (H2 O2 ) were 0, 0.5, 1, 3, 5, 10, and 20 mM. With the increased oxidation degree, the contents of α-helix, ionic bonds, and hydrogen bonds decreased significantly ( P < 0.05). Moreover, the pI value and total amino acids showed a declining trend, and the β-sheet as well as solubility rised firstly and then declined. On the contrary, random curl, β-turn, and turbidity increased significantly ( P < 0.05). Therefore, amino acid side chain groups were modified, and the opposite effect, caused by oxidation that leads to protein cross-linking and aggregation, was greater than the promotion effect, such as net negative charge, these are the main factors that leads to the instability of protein solution systems.