Background technology
Soybean protein isolate is the vegetable protein of high-quality, has multiple functional characteristic, as advantages such as gelation, emulsibility, retentivenesses.Soybean protein isolate is widely used as food ingredient.On the other hand, soybean protein isolate has certain antigenicity as the former albumen of soybean, easily makes the people, particularly children's allergy.When using soybean protein isolate to prepare acid soybean protein beverage,, influence the product sense organ in the easy precipitation of isoelectric point (pH4.2).Thereby limited the application of soybean protein isolate.
Utilize the albumen enzymatic hydrolysis method, the soybean protein hydrolysis is prepared into micromolecular soybean oligopeptide, compare with former albumen, its water-soluble and retentiveness improves a lot, and in also easily dissolving of isoelectric point, can be used to prepare acid soybean protein beverage.The soybean oligopeptide molecular weight is little, with former albumen with compare nutritionally easier being absorbed by the body with the amino acid of forming.Simultaneously, soybean oligopeptide has former albumen all and unexistent physiologically active.
Therefore, in order to obtain than soybean crude protein in nutrition, functional and hydrolysate of soybean protein goods that physiologically active is better have carried out many trials and have come soybean protein is carried out enzymolysis.For example Chinese patent publication number CN 1067226C has disclosed the method that a kind of enzymolysis prepares soybean peptide ammino acid oral liquid.With removing soybean smell albumen powder enzymolysis, the enzymolysis material is drawn supernatant to this method behind standing sedimentation, through seasoning, filtration, vacuum packaging, sterilization, make soybean peptide ammino acid oral liquid with a kind of enzyme in 1398 protease, trypsase, the bromelain.This bench scale owned by France.The CN1323535A patent is a raw material to take off the soy protein products of waking up, with plant rennet (reagent enzyme, papain, bromelin, lipoprotein enzyme) enzymolysis, filter, obtain based on the polypeptide of micromolecule polypeptide and amino acid mixing liquid or through freeze drying soya-bean polypeptides and amino acid mixing powder.This bench scale owned by France.The method that CN1082345C discloses is a raw material with the defatted soybean sheet, and through sizing mixing, acid is heavy.After again acid being precipitated curdled milk and sizing mixing, use pepsin hydrolysis, neutralization, spray-drying obtains the low soybean protein hydrolyate of glycinin content.This patent belongs to lab scale.CN1175753C has disclosed a kind of production method of not having bitter soyabean polypeptide powder.This is raw material with the soybean protein isolate, with neutral proteinase and trypsase the soybean protein feed liquid is carried out enzymolysis twice, and enzymolysis liquid filters with canvas earlier, in filtrate, add the kaolin powder, carry out the absorption first time and remove suffering reason, feed liquid standing sedimentation, siphon sucking-off supernatant.In isolated clear liquid, add activated carbon then and carry out going the second time suffering reason.To go the enzymolysis filtrate vacuum after the hardship to concentrate, vacuum drying be pulverized and is obtained not having bitter soya-bean polypeptides powder.This method is a lab scale.CN1183258C has disclosed a kind of production method of producing the soybean protein oligopeptides.This method comprises that with soybean protein soybean protein isolate, FSPC, defatted soy flour, big dregs of beans and soya-bean cake are raw material, carries out once or the secondary hydrolysis with Alcalase alkali protease and acid protease, obtains being rich in the enzymolysis liquid of little molecule oligopeptides.This method also belongs to lab scale.Because above these methods only limit to lab scale, are unsuitable for industrial production.Known document " combined-enzyme method prepares the low oligopeptides research of active soybean " adopts 2709 alkali proteases, the complex enzyme for hydrolyzing soybean protein isolate liquid that 1369 neutral protein matter enzymes and trypsase are formed, enzymolysis liquid adds the isoelectric point of acid to soybean protein, centrifugal and ultra-filtration and separation, pass through decolorizing with activated carbon again, from handing over desalination, concentrate and spray-drying, obtain the soybean oligopeptide powder.This method adopts isoelectric precipitation to separate, and need add a lot of hydrochloric acid, can make the later process difficulty, influences the mouthfeel of product, adds that it also is a lab scale, can't realize suitability for industrialized production.
Above-mentioned several method for preparing soy peptide powder all belongs to lab scale, and process conditions and effect, especially separation method are difficult to realize on large-scale industrial equipment.Realize highly purified soybean oligopeptide suitability for industrialized production, must screen suitable protease preparation, determine optimum hydrolysising condition, soybean protein is had the hydrolysis of control according to the character of protease.To select separation and purification means and desalination to go bitter method simultaneously, thereby form a perfect production technology of cover and equipment configuration, just can produce qualified, mainly contain small-molecular peptides, highly purified soybean oligopeptide powder product.
Summary of the invention
The purpose of this invention is to provide high-purity, low-molecular-weight soybean oligopeptide powder product, and the method for effective suitability for industrialized production soybean oligopeptide, comprise soy proteinaceous control enzymolysis process, separation condition and corollary equipment thereof.
The inventor discovers, the purity of soybean protein isolate raw material directly influences the purity of final products soybean oligopeptide, therefore, the present invention will reach the purpose of producing the high-purity soybean oligopeptide, selects the soybean protein isolate raw material of 90% protein content (butt).
The industrial water that the present invention selects is a deionized water, and electrical conductivity of water is 10-20 μ s/cm.Ion exchange water has been removed acid ion and metal ion, has reduced the factor that influences enzyme hydrolysis, enzyme hydrolysis condition easy to control.Simultaneously, simplify separation and purification treatment, helped improving the purity of product.
Used in the present invention is commercially available mixed protein enzyme preparation, this kind of enzyme preparation be by, form from the multiple protein enzyme that plant, animal or microorganism are extracted.Described protease acts on pH2-9 to soy proteinaceous hydrolyzation catalysis, and temperature 40-65 ℃ of scope is effective.
The degree of hydrolysis of this protein (DH) expression protein is used for observing and control enzyme hydrolysis process by the degree of enzymatic hydrolysis.Protein degree has different mensuration and method for expressing.The present invention adopts the method for measuring acid (TCL, i.e. trichloroacetic acid) molten nitrogen to measure the degree of hydrolysis of protein.The degree of hydrolysis of hydrolysate of soybean protein liquid of the present invention reaches 50~75%.
The molten nitrogen determination method of acid is as follows: take by weighing the 10ml enzymolysis liquid respectively and be equivalent to the soybean protein isolate of the solid content in the 10ml enzymolysis liquid in tool plug centrifuge tube, each adds 10ml15%TCL solution, place 5min behind the mixing, centrifugal 10min under the rotating speed of 4000r/min then, get whole supernatant liquors, decide the nitrogen method according to routine and handle, measure.Other takes by weighing the soybean protein isolate that is equivalent to the solid content in the 10ml enzymolysis liquid and decides the nitrogen method according to routine and handle, and measures total nitrogen.Be calculated as follows degree of hydrolysis then:
DH=(N
3-N
2)/(N
1-N
2)×%
In the formula:
The degree of hydrolysis of DH-soybean protein;
N
1Total nitrogen in the-soybean protein isolate;
N
2Sour molten nitrogen in the-soybean protein isolate;
N
3Sour molten nitrogen in the-soybean protein hydrolysis liquid.
The present invention adopts the combination piece-rate system to carry out the separating treatment of hydrolysate of soybean protein liquid.One of unit of combination piece-rate system is a disk centrifuge, and its rotating speed is at 4000r/min-12000r/min, and treating capacity is 10000L/h-20000L/h; Two of the unit of combination piece-rate system is ceramic membrane filter devices, and the aperture is 0.1 μ m-0.5 μ m, and water-flowing amount is 10T/h-20T/h.Three of the unit of combination piece-rate system is hollow membrane filters, and molecular cut off is 2000Dalton-15000Dalton, and water-flowing amount is 10T/h-20T/h.Adopt combination piece-rate system of the present invention that hydrolysate of soybean protein liquid is progressively separated, big molecule is less and less, be that hollow membrane filters by ultrafiltration at last, removed the polypeptide of unhydrolysed macro-molecular protein and partial hydrolysis basically, obtain being rich in the liquid that sees through of little molecule oligopeptide.
The present invention sees through liquid with the enzymolysis that separating and filtering obtains, and is concentrated into solid content 25-40% through triple effect falling film evaporation enrichment facility, goes hardship with decolorizing with activated carbon again, and last spray-dried one-tenth soybean is supported poly-peptide powder.
Soybean Peptide content in the soybean oligopeptide product of the present invention can be explained by two aspects.As everyone knows, soybean protein isolate is to be raw material with big dregs of beans, by the heavy explained hereafter of the molten acid of alkali, so that the protein of soybean protein isolate all is acid is heavy.Sour molten albumen in the soybean oligopeptide product includes only micromolecular peptide and free amino acid.The content of Soybean Peptide can deduct free amino acid with the molten albumen of acid and represent.On the other hand, by measuring the molecular weight distribution of product, can verify whether product is peptide.
The present invention adopts with the free aminoacid content in liquid chromatogram (amino-acid analyzer) the mensuration soybean oligopeptide product, and uses conventional 18-20 seed amino acid standard specimen.
The present invention adopts high performance gel filtration chromatography to measure the molecular weight distribution of protein and peptide, and method is as follows:
Instrument:
High performance liquid chromatograph is furnished with UV-detector and the chromatographic work station or the integrator that contain data processing software;
Phase vacuum filtration degasser flows
The used standard items of molecular weight calibration curve:
1) C CYTOCHROME C C (cyyochrome, MW12500)
2) antibacterial enzyme (aprotinin, MW6500)
3) the bacillus enzyme (bacitracin, MW1450)
Aminoacetic acid-aminoacetic acid-tyrosine-arginine (MW451)
Aminoacetic acid-aminoacetic acid-aminoacetic acid (MW189)
Chromatographic condition:
Chromatographic column: TSKge lG2000SWXL 300mm * 7.8mm
Phase flows: acetonitrile: water: trifluoroacetic acid, and 10: 90:
Detect wavelength: UV220nm
Flow velocity: 0.5mL/min
Column temperature: 30 ℃
Sampling volume: 10 μ L
According to the present invention, the present invention is the method for a suitability for industrialized production soybean oligopeptide.Characteristics of the present invention are, employing contains the complex enzyme formulation of multiple protein enzyme, soybean protein is carried out the multipoint directional enzyme to be cut, catalyzing hydrolysis controlledly, improved the efficient of hydrolysis, made hydrolysis be limited in the little peptide stage, and carry out effective separation and purification, make the soybean oligopeptide product, the soybean oligopeptide technological process of production is seen Figure of description.According to the present invention, the degree of hydrolysis of soybean protein reaches 40-70%, and molecular weight accounts for more than 90% at the little peptide below the 2000Dalton in the soybean oligopeptide product.
The soybean oligopeptide product of producing with the present invention shows through animal and human trial, can more effectively be absorbed by the body, and reduces hypertension, reduces blood fat, strengthens immunity, and physiologically actives such as antifatigue are the raw materials of a kind of broad-spectrum food and health food.