Effects Of Whey Peptides On Gel Properties And Myofibrillar Protein Oxidation Of Chopped Prok During Repeated Freeze-thaw Cycles

As a green and safe natural antioxidant,whey protein hydrolyzed(WPH)can delay the oxidation of pork mince and maintain the quality of meat products during repeated freeze-thaw(F-T)cycles.This experiment thoroughly explored the various effects of WPH on the quality and oxidation characteristics of meat emulsion during repeated F-T processes.The main research includes the following four aspects:1.By measuring the whiteness,p H value,texture,gel strength,Met Mb content and rheological properties of minced pork,explore the effect of WPH on the quality characteristics of repeated F-T minced pork.With the increase of the number of repeated F-T,the p H value showed a significant increase trend,and the whiteness value decreased significantly.In terms of the gel texture of minced pork,the hardness,chewiness,elasticity and cohesiveness of minced pork decreased significantly as the number of F-T cycles increased.Adding WPH can effectively inhibit juice loss and meat rancidity during repeated F-T processes,inhibit the decrease in texture properties and gel strength,and delay the decrease in rheological properties.Among them,15% WPH had the best effect,which was significantly different from other groups(P<0.05).2.By measuring the peroxide value(PV)of minced pork,thiobarbituric acid reactive substances(TBARS),carbonyl content,sulfhydryl content,and total volatile base nitrogen(TVB-N)Value and other indicators to explore the effect of WPH on the oxidation characteristics of repeated FT pork mince.It is concluded that the addition of WPH helps to inhibit the increase of PV value during repeated FT.In addition,it also inhibits the increase of protein carbonyl content,and effectively reduces the sulfhydryl content,salt-soluble protein content,and the rate of increase of TVBN value and TBARS value.Delay the degree of oxidation of minced pork.3.By measuring the surface hydrophobicity of myofibril protein,mid-infrared spectroscopy(FT-IR),salt-soluble protein content,Zeta potential,particle size and other indicators,explore the effect of WPH on the secondary structure and internal structure of myofibrillar protein in repeated FT pork minced meat.The influence of cross-linking aggregation.It is concluded that the addition of WPH helps to inhibit the decrease of ?-helical structure content and the increase of the hydrophobicity of the gel surface,and maintain a stable protein conformation.In addition,it can also enhance the content of salt-soluble protein and reduce the production of protein aggregates in the F-T cycle.The 15% effect is the best,which is equivalent to the effect of Butyl hydroxy anisd(BHA).4.Study the influence of WPH on the moisture and movement of repeated F-T myofibrillar protein gel by measuring the thawing loss,cooking loss,low-field nuclear magnetic resonance and gel water holding capacity of minced pork.It is concluded that the addition of WPH helps to inhibit the increase of cooking loss and thawing loss,increase the water holding capacity of the gel,and prevent the migration and loss of water,of which 15% has the best effect,exceeding BHA.