Study On The Effect And Mechanism Of Exogenous L-arginine And L-lysine On Tenderness Of Cooked Marinated Chicken Breast

Cooked marinated meat products are always popular with consumers because of its strong flavor and moderate tenderness.Tenderness is the most important quality attribute and sensory characteristic of cooked marinated meat products.L-Arginine?L-Arg?and L-lysine?L-Lys?have multiple effects on the quality of meat products,such as flavor,color,texture,etc;however,their effects on the tenderness and other quality characteristics of cooked marinated meat products have not been reported yet.In addition,the mechanism of these two amino acids on the tenderness of cooked marinated meat products is not clear.Therefore,the work focused on the effects of L-Arg and L-Lys on the tenderness of cooked marinated chicken breast and the possible mechanism underlying these effects;meanwhile,the effects of these two amino acids on the other quality characteristics of cooked marinated chicken breast were also investigated.The main results are as follows:1.The effects of L-Arg and L-Lys on tenderness and other quality characteristics of cooked marinated chicken breast?1?Addition of L-Arg and L-Lys significantly decreased the shear force and cooking loss?CL?and increased pH value,but did not have significant influences on the water holding capacity?WHC?of cooked marinated chicken breast.?2?Low field-nuclear magnetic resonance?LF-NMR?showed that there were four peaks in the cooked marinated chicken breast in all cases,which were 0.01-0.9 ms(T_2b),1-10 ms(T₂₁'),15-150 ms(T₂₁),and 300-2500 ms(T₂₂).Among the four peaks,the addition of L-Arg significantly shortened the T₂₁ relaxation times?from 49.77 ms to 37.64 ms?.In addition,the samples with L-Arg and L-Lys exhibited obviously higher peak area ratio(A₂₁)than the control.?3?Addition of L-Arg and L-Lys effectively promoted the extraction of salt soluble protein?SSP?from precooking marinated chicken breast,but did not change the protein components of SSP.In addition,scanning electron microscopy?SEM?showed that the gap between muscle fibers narrowed with the increased L-Arg and L-Lys.?4?The textural parameters?hardness,springiness,chewiness and cohesiveness?of cooked marinated chicken breast increased with the enhanced L-Arg and L-Lys.Meanwhile,L-Arg and L-Lys effectively improved the sensory properties?color,taste,flavor and elasticity?of cooked marinated chicken breast.L-Arg and L-Lys could improve the tenderness,water retention,texture and sensory quality of cooked marinated chicken breast.This may be related to the facts that L-Arg and L-Lys improved the pH value of cooked marinated chicken breast,promoted the extraction of SSP from precooking marinated chicken breast,captured the immobilized water of cooked marinated chicken breast and reduced the gaps between muscle fibers.2.The effect mechanism of L-Arg and L-Lys on the tenderness of cooked marinated chicken breast?1?L-Arg and L-Lys significantly reduced the shear force and increased the pH value of chicken breast.?2?Transmission electron microscope?TEM?showed that L-Arg and L-Lys destroyed the structure of myofibrils?Z-disk,M-line and I-band?and increased the sarcomere length.In addition,L-Arg and L-Lys increased myofibrillar fragmentation index?MFI?of chicken breast.?3?Sodium dodecyl sulfate polyacrylamide gel electrophoresis?SDS-PAGE?showed that L-Arg and L-Lys promoted the degradation of troponin-T.Casein zymography showed that L-Arg and L-Lys may help keep calpain activity.?4?SDS-PAGE showed that in neutral 0.2 M KCl solution?pH=7.2?,L-Arg effectively dissociated actomyosin?AM?into myosin and actin,while L-Lys was less effective.In addition,L-Arg reduced the Ca²⁺/Mg²⁺-ATPase activities of AM.?5?Fluorescence spectroscopy and second-derivative UV spectra showed that L-Arg caused the expansion of AM.L-Arg and L-Lys increased pH value to keep the calpain activity and accelerated the degradation of troponin-T.In addition,L-Arg could change the conformation of AM,which may facilitate the interaction between L-Arg and Ca²⁺/Mg²⁺-ATPase of AM and accelerate the dissociation of AM.These may help improve the tenderness of cooked marinated chicken breast.