The Research On Extraction And Application Of Kafirin

In this thesis, the aim was to extract the kafirin from sorghum, the kafirin is the mixture ofproteins in sorghum which can dissolve in the ethanol solution. On the basis of good-filmingproperty of kafirin, the film was made to improve its properties extending utilization.First of all, the extraction solvent of kafirin from sorghum was，the solvent kafirin thatextract from sorghum was solution of water and alcohol.. Extraction time, extractiontemperature, liquid-solid and ethanol concentration have been analyzed in single factorexperiment. Then on the basis of single factor experiment, according to the kafirin extractionrate, the optimum parameter with the Orthogonal design was75%EtOH and solvent to sorghumration was11:1,setting temperature at60℃，extracting1.5hours, the extraction rate was6.79%.Secondly, a high-yield method for the extraction of kafirin from Sorghum bicolor wasproposed to use an integrated ultrasonic and microwave reaction system. On the basis ofsingle-factors experiments, the response surface methodology was used to optimize extraction ofprotein. The result indicated that the the conditions of the optimum extraction are：the ultrasonictreatment time,temperature and power were31min,63℃and410W. Under the conditions, therate of extraction was7.80%.Then, in this study, the glycerin and L-cysteine were used to make the kafirin film, basedon the single factor experiment, the film-forming conditions of kafirin films were optimized byRSM, and the result were: film-forming temperature75℃, protein concentration10%(w/v), theratio of glycerol to kafirin was0.28(g/g), the addition of L-cysteine was0.90%. Under theoptimized conditions, the property indexes of the kafirin films were: tensile strength was16.13MPa, elongation strength was13.10%.At last, kafirin film was used to keep pork fresh. The total bacteria number of stored porkwere determined, the results show that using kafirin film can retraining the growth ofmicroorganism, extend shelf-life and maintain the quality of the pork. Group with films andgroup without films have better bacteriostasis. The films that added0.075gNisin to1kg porkhave better antimicrobial effections than contrast group with films. Stored fats wereiodometrically titrated to determine peroxide value, the result show that the kafirin films cansignificantly delay the oxidation of fat, the two groups have visible significant difference(p<0.01).