| Rabbit meat is rich in nutrients with high protein,phospholipid,polyunsaturated fatty acid and digestibility,as well as low fat,cholesterol and calories.With these characteristics,rabbit meat can meet the needs of modern consumers for healthy diet.China is the country with the highest output and export of rabbit meat products around the world,but the consumption of rabbit meat lags behind some Mediterranean countries.One of the reasons is that the tenderness and water holding capacity of rabbit meat will decrease after hot processing,resulting in the dry and hard taste,poor elasticity and chewability.Improving the tenderness and water holding capacity of rabbit meat is an important prerequisite for further processing.In this condition,the tenderizer treatment is an effective tenderizing method with low cost,high tenderizing efficiency and safety.With the in-depth study of tenderizer at home and abroad,the compound tenderizer has become a research hotspot.Compared with the single tenderizer,it can not only improve the tenderizing effect,but also avoid the phenomenon of excessive tenderization.Therefore,the research object of this program was the hind leg meat of irah rabbit,which mainly focused on the following three aspects:?1?In order to study the effective tenderizer,taking the shear force and cooking loss as the dependent variables,the tenderizing effect of calcium chloride,figs protease and kiwifruit protease on rabbit hind leg meat in the form of single and compound were studied.The results showed that the effect of the compound of the three stuffs was more significant;then the proportion of the three was optimized by response surface method;the tenderizing conditions were optimized by orthogonal test;finally,the shear force,cooking loss,MFI and texture analysis were used as the index of verification test.The results showed that the most significant tenderizing effect was obtained when the concentrations of calcium chloride,fig protease and kiwi protease were 18 mg/L,11 mg/L and 6mg/L,as well as the conditions were pH 8.0,temperature 30? and time 90 min.Compared with the control group,the shear force,cooking loss and hardness of the treated group decreased by 50%,17%and 65%respectively,and the MFI as well as elasticity increased by 54%and 40%respectively.The results showed that the compound tenderizer could significantly improve the tenderness and water holding capacity of rabbit meat.?2?To study the synergistic tenderization mechanism of compound tenderizer composed of calcium chloride,fig protease and kiwifruit protease on the structure of myofibrillar protein in rabbit hind leg meat.When the MFI of the compound group no longer changed significantly?P>0.05?,the time node was the end point?180min?.The MFI,myofibrillar protein solubility,SPC,myofibrillar protein surface hydrophobicity and SDS-PAGE of the rabbit meat treated by the compound group,calcium chloride group,kiwi protease group and figs protease group were compared.Among all the indexes,MFI of the compound tenderizer was significantly improved,which showed that with the treat of the compound tenderizer,the degradation of myofibrillar protein and the increase of meat tenderness in the same time are significantly higher than that of the single group?P<0.05?;the protein surface hydrophobicity in the four groups increases first and then decreases,which showed that in the tenderization process,myofibrillar protein structure first expands and then aggregates,and the hydrophobicity of the compound group is the highest,The results showed that the protein,which under the treat of compound group,unfold and exposed more hydrophobic amino acid residues.The surface hydrophobicity of the calcium chloride group was better than that of the other two single enzyme groups?P<0.05?,indicating that the main function of calcium chloride in the compound tenderizer was to change the protein structure.The solubility of myofibrillar protein in the compound group was the highest?P<0.05?,and the two kinds of protease were significantly higher than that in the calcium chloride group,which indicated that the main role of protease in the compound tenderizer was to degrade myofibrillar protein,and the SPC in the calcium chloride group was significantly lower than that in the two single enzyme groups,which also confirmed the limited degradation of protein with the treat of the calcium chloride group.The SDS-PAGE showed at 90 min,the bands of macromolecular proteins in the compound group were obviously shallower and narrower,which further showed that the compound group had higher tenderization efficiency.The bands changed in the calcium chloride group were mainly foused on troponin T which maintained the cell structure,the result showed that the main role of calcium chloride was to make the protein structure lose stability.In addition,the SDS-PAGE also showed that fig protease mainly degrades myosin light chain,C protein and kiwifruit protease foused on degrading myosin heavy chain.The above results showed that the complex system has synergistic effect on MP degradation.The mechanism may be due to the loss of stability of MP induced by calcium chloride,with the expansion of MP structure,more enzyme binding sites were exposured,at the same time,the combination of different specificity of the two proteases also enhanced protein degradation and solubilization.?3?In order to study physical and chemical properties as well as microbial properties of rabbit meat after the tenderized treatment during storage and to determine the shelf life at-4? and-18?,the tenderized group,which with compound tenderizer?CaCl2,fig protease and kiwifruit protease?and blank group were storaged at–4? and-18? respectively.the changes of TAC,pH,TVB-N,TBARS,shear force,cooking loss and color of two groups were compared.The results showed that the TAC of tenderized group was lower than that of blank group,and the pH,TVB-N and TBARS of tenderized group were higher than that of blank group.Tenderized rabbit meat could maintain good tenderness,color and low cooking loss within 15 days at-4?.Within 30 days at-18?,the shear force and cooking loss of tenderized group changed little,but the color stability was lower than that of blank group.Therefore,the freshness of tenderized rabbit meat decreased more quickly though it had some bacteriostatic effect.The shelf life of tenderized rabbit meat were 15 days at-4? and 30days at-18?,but the color deterioration of tenderized group was significant at-18?. |
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