Study On Soybean Peptide Debitterizing And Physiological Function

Soybean peptide is a kind of biological active peptide from hydrolyzing soyabean protein.But because of its heavy bitter taste, only be used in aquaculture, cosmetics, medicine fieldcurrently, limitting its application in the field of food severely. In order to making it havegood taste and improving their application, taking off its bitter taste is a very important work.Traditional methods of debitterizing soybean peptides can cause of soybean peptide functionloss. This experiment adopted three methods to take off the bitter of soybean peptide:β-Cyclodextrine method, enzymatic hydrolysis and microbial method. And by comparing thepeptide molecular weight in the soybean peptide, peptide content changes, the change ofphysiological function between before and after being debitterized, compareing thedebitterizing effect of three methods above. Getting to the debitterizing process that will takeoff the bitter at the same time will not result in a loss of the function of soybean peptide.Experiment explores the method of debitterizing uesd by β-Cyclodextrine. Using singlefactor experiment and response surface experiment explores the best condition of debitterizingsoybean peptides uesd by β-Cyclodextrine: pH6.7, hydrolysis temperature40℃, quality ratioof β-Cyclodextrine to soybean peptides1:4, and time40min. Under this condition, the tasteof the soybean peptide get some improvement. The downside is that, the addition ofβ-Cyclodextrine will produce certain anxious burnt flavour, affectting its flavor.Experiment explores the method of debitterizing uesd by composite enzyme solutionwith Protex51FP and Protex6L. First of all, determing the Protex6L and Protex51FP forexperiment through the experiments about degree of hydrolysis. Using single factorexperiment and response surface experiment explores the best condition of debitterizingsoybean peptides uesd by complex enzyme: pH7.2, hydrolysis temperature50℃, activity ratioof Protex51FP to Protex6L3:2, total enzyme dose6000U/g, and hydrolysis time3h. Underthis condition, the taste of the soybean peptide get some improvement obviously. Thespectrogram of gel chromatography show that, the molecular weight of soybean peptide afterdebitterizing has been smaller obviously, instructing that, the protease play a role to the aminoacids about of bitter taste, shortening the peptide chain. The peptide content changed little between before and after being debitterized, lost only2.3%. At the same time, the anti-fatiguephysiological experiment also showed that, compared with no debitterizing group, compositeenzyme bitter group show: swimming short time by5.8%(p>0.40), low residual amount ofhepatic glycogen of3.8%(p>0.50), low muscle glycogen amount remaining13.2%(p>0.08),blood urea nitrogen content is6.4%(p>0.30), blood lactic acid content is2.8%(p>0.50), Thissuggests that there was no significant difference of aoybean peptide physiological functionbetween before and after being debitterized used by composite enzyme. Compared with thetraditional debitterizing soybean peptide enzyme method, this study used a combination ofenzyme and enzyme debitterizing soybean peptide, the experimental results show that thedebitterizing effect of this method is better than the single use of external enzyme for soypeptideExperiment explores the method of debitterizing: preparing acid protease fromfermenting Aspergillus Niger, then using the acid protease to debitter soy peptide. First of all,activating the Aspergillus Niger strains used by the solid medium. Then, enlarging theAspergillus Niger strains used by the fluid medium. Next, fermenting Aspergillus Nigerstrains used by the bran to produce the acid protease. Finally, debitterizing the soybeanpeptides with the acid protease filtrate. Using single factor experiment and response surfaceexperiment explores the best condition of debitterizing soybean peptides used by acidprotease from fermenting Aspergillus Niger strains: pH6.0, hydrolysis temperature50℃andhydrolysis time2.1h. Under this condition, the bitter taste value is about1, reducing4~5bitter taste value, the effect of debitteration is very obvious. The spectrogram of gelchromatography show that, the molecular weight of soybean peptide after debitterizing hasbeen smaller obviously, instructing that, the acid protease from Aspergillus Niger play a roleto the amino acids about of bitter taste, shortening the peptide chain. Debitterizing almost didnot cause loss of polypeptide between before and after being debitterized, lost only0.13%. Atthe same time, the anti-fatigue physiological experiment also showed that, compared with nodebitterizing group, Aspergillus niger debitterizing group show: swimming short time by3.8%(p>0.40), low residual amount of hepatic glycogen of0.42%(p>0.80), low muscleglycogen amount remaining7.8%(p>0.10), blood urea nitrogen content is3.8%(p>0.30),blood lactic acid content is2.3%(p>0.50), This suggests that there was no significant difference of soybean peptide physiological function between before and after beingdebitterized used by Aspergillus niger. From the energy consumption into consideration,using Aspergillus niger to debittere soybean peptide has an obvious advantage over othermethods. But says from the debitterizing effect, this method is a little lower than directenzymatic hydrolysis. This is due to the fermentation of acid protease enzyme activity is low.If optimizing the conditions of enzyme production further, then we can get the Aspergillusniger strain of producing higher enzyme activity. Believe that, microbial debitterizing methodwill be one of the best debitterizing methods, not only debitterizing effect is good, but alsoconsume less energy and experiments.The three methods above, effect of debitterizing are superior to traditional methods. Butthe addition of β-Cyclodextrine can dope certain anxious burnt flavour, so the effect is notvery good. The debitterizing effect of acid protease from Aspergillus Niger is good. And thecost is much lower than that of enzymatic hydrolysis. The loss of the polypeptide is less andless than enzymatic hydrolysis. So make sure the microbial method is the best way todebitterizing soy peptide.