Effects Of Gallic Acid And Chlorogenic Acid On The Properties Of Phosphorylated Myofibrin From Chicken Breast

Myofibrin has the highest proportion in the content of muscle protein,so it determines the physical and chemical characteristics and sensory quality of muscle products,directly affects the processing suitability and storage period of muscle products.Protein modification is a hot research area,and phosphorylation has been proved to be a reliable method to improve protein function.Gallic acid and chlorogenic acid is a kind of natural plant polyphenol compounds,antioxidant,antitumor,anti-inflammatory and other bioactive functions,because more phenolic compounds can be combined with protein,change of protein structure,in turn,affects protein functional properties,therefore as a natural antioxidant used in meat products has a good prospect.To provide a theoretical basis for the production and processing of chicken breast meat products by polyphenol synergistic phosphorylation,this topic based on the optimization of myofibrin phosphorylation technology,two polyphenols,gallic acid and chlorogenic acid,were selected as additives to investigate the effect of phosphorylated myofibrin on antioxidant and functional properties.The oxidative system was established to further study the effect on protein structure and function.Finally,the storage quality of chicken meatballs with chlorogenic acid and phosphate was studied and the shelf life was predicted.The main findings are:1.Chicken breast as raw material,myofibrillar proteins were phosphorylated with sodium tripoly phosphate(STP).On the basis of single-factor investigation,response surface methodology was employed to establish optimum conditions for phosphorylation.The results showed that the optimal conditions of myofibrillar protein phosphorylation were pH 7.52,protein concentration 15.36 mg/mL,NaCl concentration 0.75 mol/L,reaction time 2 h,and STP content 3.40%.Under this condition,the degree of phosphorylation was 99.001 mg/g.The degree of protein phosphorylation obtained by simulating the actual processing of meat products was close to the experimental results,which proved the feasibility of phosphorylation.2.Two polyphenols,gallic acid and chlorogenic acid,were selected to investigate the effects of different concentrations of gallic acid and chlorogenic acid on the antioxidant and functional effects of phosphorylated chicken breast myofibrin.The results showed that the synergistic effect of polyphenols and phosphorylation significantly increased the antioxidant activity of myofibrin.the emulsifying activity,emulsifying stability and turbidity were increased because of the addition of polyphenols.With the increase of polyphenol concentration,emulsifying activity and emulsifying stability first increased and then decreased.Low medium concentration had little effect on turbidity.High concentration reduced turbidity significantly.Compared to chlorogenic acid,gallic acid had more significant effects on various aspects of gel properties;as the concentration of polyphenols increased,the gel hardness first increased and then decreased;the gel elasticity didn't change significantly;the gel whiteness first decreased and then increased with the increase of chlorogenic acid concentration,and decreased with the increase of gallic acid concentration.The water retention of the gel gradually increasedas the concentration of polyphenols increased.3.The linoleic acid oxidation system was established,and the effects of different concentrations of chlorogenic acid and gallic acid on the structure and function of phosphorylated chicken breast myofibrin were studied.The results showed that chlorogenic acid and gallic acid generally inhibited protein carbonyl formation and prevent sulfydryl losses caused by oxidation.FTIR indicated that the addition of chlorogenic acid and gallic acid in the oxidizing system resulted in the weakening of the amide I and II bands of phosphorylated myofibrin,at the meantime,intensified oxidation-initiated loss of?-Sheet conformation.Effect of oxidation on tertiary structure was demonstrated by tryptophan fluorescence and surface hydrophobicity.Tryptophan was protected by the introduction of phosphate groups,but the effect of polyphenols on endogenous tryptophan was dose-dependent,accompanied by increase of surface hydrophobic group.The functional characteristics changes with 40 and 100?g/mL chlorogenic acid/gallic acid led to a widely enhanced,but with 60?g/mL chlorogenic acid and 80?g/mL gallic acid led to a remarkably reduced.4.Three different storage conditions was setted up,and the color difference,pH value,total number of colony and sensory evaluation of cooked chicken meatballs with chlorogenic acid and phosphate were studied.The results showed that the higher the storage temperature,the faster the index change rate of chicken meatballs.The change of the total number of colonies of chicken meatballs at different storage temperatures was consistent with the first-order reaction,and the reaction rate constant was consistent with the Arrhenius equation.It can predict that shelf life at different temperature of cooked chicken meatball by the model which was fit well.The Arrhenius equation of the quality change of the chicken meatball was obtained:k=2.13×10~8exp(-50593/RT).