The restorative role and mechanism of L-lysine in yak myofibrillar protein gelling properties under malondialdehyde-induced over-oxidation damage
Hui-Qin Lu, Linlin Wang, Lina Wang, Yi-Wen Mei, Cai-Hui Wang, Bi-Feng Xu, Na-Li
Abstract
The effects of different concentrations of L-lysine (L-lys, 5 mmol/L, 10 mmol/L, 15 mmol/L, and 20 mmol/L) on the structure and gelling behavior of yak meat myofibrillar protein (MP) under the oxidative stress of malondialdehyde (MDA) were explored. L-lys substantially inhibited the oxidation-induced structural deterioration of the proteins, and restored the gelation performance. Intrinsic tryptophan fluorescence and Fourier transform infrared spectra analysis confirmed that the addition of L-lys enhanced the structural stability of MP. L-lys also appreciably decreased oxidation-induced protein crosslinking and aggregation, as shown by particle size and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Moreover, the repair effect of L-lys on MP oxidative damage showed a significant concentration-dependent effect, in which L-lys showed the best repairment at a concentration of 20 mmol/L. These results advocate that oxidation disrupted the structure and gel characteristic of MP, but L-lys effectively restored these destructive changes.