The Study On The Edible Cow Hoof And Cowhide Dehairing Method And Nutritional Quality

The nutritional value of cow hoof and cowhide are rich and is widely eaten,but all the edible parts are covered by hairs,which bring some difficulties for eating.At present,the methods of hair removal at home and abroad are enzyme method,alkali perm,steam hair removal,and rosin glyceride dehairing,but all of them have the disadvantages of low dehairing efficiency and many harmful residues.To study a more efficient and clean method of dehaieing,In this experiment,the post slaughter cow hoofs and cowhides were divided into fresh and frozen groups,with different dehairing methods,single factor,orthogonal and response surface test were carried out with the indexes of hair removal rate,collagen and sensory evaluation,and the best dehairing process and parameters were obtained.The mechanism of the dehairing and the effect of different methods on the quality of cow hoofs and cowhides were studied.The main conclusions are as follows:manual?1?The best process of blanching dehairing is:material washing,pruning treatment,hot blanching,mechanical?manual?dehairing,pruning treatment and rinsing.the best processing parameters of blanching process are:2h after the slaughter time,blanching temperature was65?,blanching time 10min,and the hair removal rate was 97.11%under these conditions.?2?The combined alkaline-enzymatic unhairing process was developed for the chilled group hoofs and cowhides.The best process was as follows:raw material thawing,pruning treatment,swelling process,enzyme treatment,mechanical hair removal,pruning treatment and rinsing,The alkali and enzyme used in this experiment are edible alkali and alkaline protease respectively.a.Through the L₉?3⁴?orthogonal test,it is concluded that the process parameters for the alkaline swelling of the cow hoofs was 15h,the concentration of alkaline solution was 4%and the time of water swelling was 16h,the rate of swelling was 4.99%under this condition;the process parameters for the alkaline swelling of the cowhides was 20h,the concentration of alkaline solution was 5%and the time of water swelling was 16h,the rate of swelling was4.95%under this condition.b.The optimum processing parameters for the enzyme treatment of cow hoofs are as follows:the enzyme hydrolysis temperature was 48?,the pH was 9.7,the enzyme hydrolysis time was 3.2h,and the amount of enzyme added was 0.4%.Under this condition,the hair removal rate of cow hoofs was 90.90%;the optimum processing parameters for the enzyme treatment of cowhides are as follows:the enzyme hydrolysis temperature was 50?,enzyme solution pH10.0,enzyme hydrolysis time 2.5h,enzyme addition was 0.3%,and the hair removal rate was 91.98%.?3?Through the observation of the microstructure can be obtained without enzyme treatment of cowhide the hair roots in the pores are visible,and enzymatically treated leather pores appear empty,it was proved that the combined alkaline-enzymatic unhairing process can achieve a effective hair removal effect;the swelling process has played the role of loose,expanding cow hoofs and cowhide collagen fibers.?4?Through the exploration of the mechanism of swelling,it is concluded that a certain concentration of alkaline solution can hydrolyze the protein and mucin like proteins around the hair follicle and the fibrous interstitial,and decompose the collagen fiber,and to a certain extent,it has the effect of loosening,expanding the cow hoof and skin collagen fibers.?5?There was no significant change in other nutritional indexes except for water and protein?P<0.05?Among these two dehairing methods.the combined alkaline-enzymatic unhairing method increased the moisture content of the products by 3.4%,and the protein decreased by 9.37%.