Response Of Potential Biomarkers Of Lamb Quality To Environmental Factors

Lamb is an important source of high-quality meat and is more preferred by consumers.Tenderness,color and water-holding capacity are important indexes to evaluate the quality of lamb,which are mainly determined by the source of raw and biochemical changes such as glycolysis,energy metabolism,heat stress,protein oxidation and apoptosis in postmortem.It was found that heat shock proteins(heat shock protein 27(Hsp27),heat shock protein 70(Hsp70))and metabolic enzymes(triosephosphate isomerase(TPI1),phosphate glucose mutase(PGM),enolase 3(ENO3)and pyruvate kinase isoenzyme(PKM)could be used as the potential biomarkers to characterize meat quality.These biomarkers are affected by temperature and packaging conditions during processing and storage of meat in post-mortem,but there is a lack of systematic research.In this study,lamb meat was taken as the research object to analyze the expression and response levels of Hsp27,Hsp70,TPI1,PGM,ENO3 and PKM under different environmental factors(chilling rate and packaging gas composition),and their relationship with meat quality.In order to comfirm whether these could be used as biomarker of lamb quality in post-mortem,and provide the reference for developing the technology to maintain and detect lamb quality.The specific research results are as follows:(1)The longissimus dorsi muscle of lamb with different chilling rates(4.8?/h,5.1?/h,23.0?/h,25.1?/h)was used as experimental materials.The responses changes of meat quality(pH value,shear force,color,cooking loss)and potential biomarkers(Hsp27,Hsp70,TPI1,PGM,ENO3,PKM)were measured,and the relationships among chilling rate,meat quality and potential biomarkers were analyzed,and analyzed the correlation between chilling rates,meat quality and potential biomarkers.The results showed that compared with other chilling rates,the response of Hsp27 was obvious at 25.1?/h,and its relative expression was the highest(P<0.05),and the relative expression of Hsp70 was the lower,and the shear force value of lamb was lower in postmortem 12 h-1 d.During the whole storage process,the relative expression of TPI1 at 23.0?/h was significantly higher than the other three treatment groups(P<0.05),and the cooking loss was significantly higher than that of the other three treatments groups(P<0.05).The relative expression of TPI1 at 25.1?/h chilling rate was significantly lower than that 23.0?/h(P<0.05),while the relative expression of PGM was significantly higher than that 23.0?/h(P<0.05),and the shear force was significantly lower than that 23.0?/h(P<0.05).The relative expression of TPI1 at 25.1?/h chilling rate was significantly lower than that 23.0?/h(P<0.05),the relative expression of PGM was significantly higher than that 23.0?/h(P<0.05),and the shear force was significantly lower than that 23.0?/h(P<0.05).At 1-7 days after slaughter,the relative expression of TPI1 at 25.1?/h was significantly lower than 23.0?/h(P<0.05)the relative expression of PGM was significantly higher than that 23.0?/h(P<0.05),and the L*value was higher and the cooking loss was lower.At 3-7 days after slaughter,the relative expression of PKM at 5.1?/h was significantly higher than that at 4.8?/h(P<0.05),the L*value,a*value and cooking loss were significantly higher than 4.8?/h(P<0.05).(2)The longissimus dorsi muscle of lamb was used as the experimental materials in air packaging,vacuum packaging,high oxygen modified atmosphere packaging(75%O2+25%CO2)and low oxygen modified atmosphere packaging(50%O2+50%CO2)for 1h postmortem.The response changes of meat quality(pH value,shear force,color,cooking loss)and potential biomarkers(Hsp27,Hsp70,TPI1,PGM,ENO3,PKM)were measured,and the relationships among packaging mode/gas composition,meat quality and potential biomarkers were analyzed.The results showed that compared with other treatment groups,the response of Hsp27 in vacuum packaging group was obvious at 6 h after slaughter,its relative expression was the highest(P<0.05),and the cooking loss was the lowest(P<0.05).The relative expression of Hsp70 in vacuum packaging group was significantly lower than that in air packaging and modified atmosphere packaging at 72 to 144 h after slaughter(P<0.05),and the relative expression of TPI1 and PGM in vacuum packaging group was significantly lower than that in the other three treatment groups at 24 to 72 h(P<0.05),the shear force was lower,and the L*value was higher.At 144 h after slaughter,the relative expression of TPI1,PGM and PKM in the high oxygen modified atmosphere package group were significantly higher than those of the other three treatment groups(P<0.05),and the shear force was significantly higher than that in the other three treatment groups(P<0.05).The relative expression of ENO3 in vacuum packaging group was significantly higher than that in air packaging and modified atmosphere packaging(P<0.05),and the shear force value of lamb was the lowest(P<0.05).