Effect Of Resveratrol And Lactic Acid On Quality And Shelf Life Of DFD Beef Patties

DFD(Dark,Firm and Dry)Beef,also known as Dark Cutting Beef,is a heterogeneous meat with dark appearance,harder texture than normal beef,less juice and slightly dry surface,high p H value(≥ 6.09),poor microbial stability and short shelf life.At present,although many measures have been taken to reduce the incidence of DFD beef,there is still a certain incidence of DFD beef in China,which brings huge economic losses to the beef processing industry.In recent years,natural antioxidants and preservatives are favored because of their low toxicity and high safety,so the search for natural active components with antioxidant and antibacterial properties has become a research hotspot.Therefore,this study aimed at using DFD beef as a raw material processed into patties in the process of color deterioration and short shelf life,choose different concentration of resveratrol and lactic acid on DFD patties for processing,in order to good in using DFD beef tender degrees,on the basis of improving the quality of the DFD patties,delay the color deterioration,inhibition of lipid oxidation,extend the shelf life,improve the effective utilization and economic benefit of DFD beef.The longest dorsal muscle of Simmental crossbred herd(p H ≥ 6.10 at 24 hours after slaughter)was selected as the raw material.The research was divided into two parts: In the first part,according to the production process of beef patties,0.025,0.05,0.075,0.1,0.125 g/kg of resveratrol and 0.05%,0.1%,0.15%,0.2%,0.25% of lactic acid were added to DFD patties,respectively,then packed the patty tray and refrigerate it at 0～4℃ for 0,4,7 days.The microbial index,meat color index(L*,a*,b*),quality index(p H value,sensory evaluation)and lipid oxidation index of DFD patties were determined at different storage time to study the effect of single factor of lactic acid and resveratrol on the quality and shelf life of DFD patties.Based on the results of the first part of the experiment,lactic acid and resveratrol were added to DFD beef patties in a two factors,three levels orthogonal design for a seven-day storage period.The optimal combination concentration was determined according to the microbial index,meat color index and quality index,and the effect of the optimal formula on the quality and shelf life of DFD beef patties was further studied.The main results of this study are as follows:(1)Resveratrol concentration optimization: Resveratrol has significant antibacterial color antioxidant effect,but no effect for DFD patties p H value,eating quality of patties improved to a certain extent,while adding concentration on p H and there was no significant difference in eating quality,etc,combined with bacteriostatic effect and color stability,we selected the optimal adding concentrations of resveratrol is 0.05 g/kg,on this basis,the next step of optimization experiment.(2)Lactic acid concentration optimization:Lactic acid can significantly inhibit microbial growth,maintain stable meat color,and reduce the p H value of DFD patties.There was no significant difference between 0.2% and 0.25% lactic acid in the antibacterial and color protection effect.The lipid oxidation level of 0.25% lactic acid treatment group was higher than that of 0.2% lactic acid,and 0.25% of the sensory evaluation had a certain sour taste and odor.Considering the economic factors and the results of lipid oxidation and evaluation,the optimal concentration of lactic acid was selected as 0.2%,and the next optimization experiment was carried out on this basis.(3)The optimal concentration and optimal combination of resveratrol and lactic acid on the preservation effect of DFD beef patties during the storage period: the optimal combination of 0.05 g /kg resveratrol and 0.2% lactic acid was determined by the orthogonal experiment results of the total number of bacterial colonies,a* value,TBARS,and overall sensory acceptability.After the DFD beef patty was treated with 0.05 g /kg resveratrol and 0.2% lactic acid,the total number of bacterial colonies in 11 days of storage still did not exceed 7 log value,while the control group reached the spoilage standard in 7 days,which also had a significant inhibitory effect on enterobacter bacteria.The results showed that resveratrol combined with lactic acid could significantly improve the antibacterial effect.Look from the sensory evaluation results in the control group storage can not accept,7 days to 11 days full of corruption,and distribution of treatment group is still in the acceptable range,0.05 g/kg of resveratrol and 0.2%lactic acid optimization combination can effectively restrain metmyoglobin accumulation,delay the color deterioration,inhibition of lipid oxidation,and then improve the DFD patty quality and prolong the shelf life of at least 4 days.