A kind of method of enzyme modification lactoprotein and application thereof
Technical field
A kind of method of enzyme modification lactoprotein and application thereof relate to the dairy products biotechnology.
Background technology
Lactoprotein is the important nutritional labeling in mammal Ruzhong, is 0.9~5.5% (seeing Table 1) at its content of human and animal Ruzhong.Global milk production is about 56 * 10 every year
7Ton, wherein 85% from cow, and 11% from buffalo, and 2% from sheep, and other 2% from goat.In general, milcher institute milk productions such as camel, yak, horse and reinder are less, although they are quite important in some area.Suppose in milk cow, buffalo, the galactopoiesis of sheep and goat institute and contain 3.4%, 3.8%, 5.5% and 2.9% protein respectively that the amount of so annual whole world institute galactopoiesis albumen is approximately 20 * lO
6Ton.
The component content of the different mammalian milk of table 1 (%)
Kind | Total protein | Fat | Lactose | Ash content |
Human goat cow buffalo Asiatic elephant sheep | ????O.9 ????2.9 ????3.4 ????3.8 ????4.9 ????5.5 | ????3.8 ????4.5 ????3.7 ????7.4 ????11.6 ????7.4 | ????7.0 ????4.1 ????4.8 ????4.8 ????4.7 ????4.8 | ????O.2 ????O.8 ????0.7 ????0.8 ????0.7 ????1.O |
Lactoprotein mainly is made up of casein and lactalbumin.What the animal breast was precipitated out from the Ruzhong after acid or enzyme processing is casein, and the maintenance dissolved state is lactalbumin.Casein contains four kinds of basic protein, i.e. α
s(comprise α
S1-, α
S2-), β-and κ-casein, account for total caseic 48% (38%, 10%), 36% and 12% respectively.Most important protein is beta lactoglobulin and ALA in the lactalbumin, and they account for 70%~80% of protein content in the whey.Other lactalbumin mainly comprise immunoglobulin (Ig),
Peptone and seralbumin.
Cow's milk is topmost in the world milk protein sources, cow's milk forms one of protein resource into human consumption figure maximum because of being of high nutritive value, its topmost nutritive effect is embodied in the infant formula as in the nutraceutical of doing godmother's dairy products or the elderly, patient.For most of normal persons, lactoprotein can be digested and assimilated, and for baby particularly ewborn infant and some the elderlys, patient or indigestion person, wherein α
s-casein just is difficult for being digested and assimilated, and beta lactoglobulin is the sensibiligen that becomes vomiting, diarrhoea etc.Therefore, for the digestibility and the sensitization that solve lactoprotein, world milk industry developed country is all conducting a research, and main research work concentrates on enzyme modification and removes α
s-casein, enzyme process or chemical method, membrane separation process are removed beta lactoglobulin.The application of these researchs remains at present in some difficulties: (1) cow's milk needs to separate casein and lactalbumin, and respectively lactalbumin and casein is carried out modification after degreasing, and reorganization is handled again, and process route is long, can not realize industrialization; (2) sensitization of elimination beta lactoglobulin, the external salting out method (FeCl that adopts usually
3Deng salt), with the beta lactoglobulin selective precipitation, this method is brought the problem of back road action need desalination, simultaneously owing to removed beta lactoglobulin and the part ALA that accounts for main ratio in the cow's milk whey fully, make that the recovery of protein rate is 30% only in the whole whey, cause the product cost height.Protein solution concentration after saltouing in addition is low excessively, for suitability for industrialized production is brought great difficulty; (3) enzyme hydrolysis α s-casein produces serious bitter taste both at home and abroad; (4) directly enzyme is put into lactoprotein during enzyme hydrolysis, make to be introduced into exogenous M-band matter in the lactoprotein, easily cause food-safety problem.
Summary of the invention
The objective of the invention is to propose a kind of method and application thereof of enzyme modification lactoprotein, adopt complex enzyme that lactoprotein is carried out the enzyme modification of " one-step method ", the optionally α in the lactoalbumin hydrolysate
s-casein and beta lactoglobulin make α
s-caseic digestibility improves and the sensitization of beta lactoglobulin reduces, and does not produce bitter taste.Lactoprotein after the modification of the present invention wherein lactalbumin and caseic ratio can reach the albumen that is similar to human milk and forms, and digestibility is high and sensitization is low, in the dairy products that are applied to be suitable for the elderly, patient or indigestion person in the laboratory milk of ewborn infant.
Technical scheme of the present invention: milk protein solution with ion regulation protein structure and heat treated, is used the α in the immobilization complex enzyme one-step method lactoalbumin hydrolysate again
s-casein and beta lactoglobulin make it simultaneously by the modification of enzyme selectivity ground, and the control hydrolysis degree prevents the enzyme modification technology that bitter taste produces, again by removing by filter the immobilization complex enzyme.
Raw materials used lactoprotein is the skimmed milk of animal breast after degreasing separates, and comprises casein and lactalbumin, fat content≤0.2%; Or in skimmed milk, add desalted whey powder, add the ratio that the desalted whey powder quality is skimmed milk volume 5~15% a mass/volume ratio; Or in skimmed milk, add soybean protein, be the ratio of skimmed milk volume 3~10% mass/volume ratio with the soybean protein quality; Protein concentration is 3~10% in the milk protein solution.
Lactoprotein is carried out ion modulin structure and heat treated: in milk protein solution, use Ca
2+, K
+And Na
+Solution in 1~2: 1~2: 1 ratio is regulated ion concentration, makes pH reach 7.0~7.5.Use the CaCl of 3mol/L during operation
2, the NaOH of 10mol/L and the KOH of 10mol/L be added dropwise in the milk protein solution, makes pH be neutrality or alkalescence, and protein peptide chain is launched, and is easy to the effect of enzyme.Milk protein solution is warming up to 70-90 ℃, keeps 5-15s, be cooled to 40-65 ℃ then.
The immobilization complex enzyme is to be carrier with sodium alginate (alginate) or shitosan (chitosan) or alginate, glutaraldehyde is as crosslinking agent, adopt the immobilization complex enzyme of a kind of high vigor of carrier cross-linking method preparation, it is 1~5% solution that sodium alginate or shitosan or sodium alginate and shitosan are mixed with concentration, is that 1: 10~50 ratio adds complex enzyme in enzyme and carrier mass ratio.Shitosan should be with the acetum dissolving of 1%-2%, after 6mol/L NaOH transfers pH to 7.5, drain and with the washing of the phosphate buffer of pH7.5, and then adding enzyme liquid, stirring and adsorbing 30-40min drips down glutaraldehydes at 10~35 ℃, and glutaraldehyde concentration is 0.3~0.8% to the solution, drain behind the stirring reaction 5~10 hours, water flushing the immobilization complex enzyme.
The same one-step hydrolysis of complex enzyme, used enzyme is: papain, bromelain, pepsin, trypsase; Used complex enzyme is the combination of two kinds of enzymes in the above-mentioned enzyme, the amount ratio of two kinds of enzymes is 4~6: 6~4, the total consumption of complex enzyme is 0.2 ‰ of lactoprotein quality~1 ‰ in the hydrolysis, the immobilization complex enzyme is added in the milk protein solution, 45~65 ℃ of following stirring reactions 1~4 hour, the control hydrolysis degree makes α
sThe degree of modification of-casein and beta lactoglobulin reaches 50%~95%.
Milk protein solution behind the enzymolysis is filtered, remove the immobilization complex enzyme, and be cooled to below 40 ℃.
The enzyme modification of cow's milk prepares the ewborn infant laboratory milk, in skimmed milk, add desalted whey powder, to add the desalted whey powder quality be that the ratio of skimmed milk volume 5~15% mass/volume ratio is carried out enzyme modification, milk protein solution after the hydrolysis is through the prescription reorganization, carry out homogeneous again, concentrate, spray-drying makes milk powder, every 100g milk powder, control protein 12~18g, fatty 25-31g.
The dairy products of the suitable indigestion person of enzyme modification preparation of cow's milk or patient, designed for old people, in skimmed milk, add soybean protein, be that the ratio of skimmed milk volume 3~10% mass/volume ratio is carried out enzyme modification with the soybean protein quality, milk protein solution after the hydrolysis is through the prescription reorganization, carry out homogeneous again, concentrate, spray-drying makes milk powder, every 100g milk powder, control protein 20-26g, fatty 10-16g.
The assay method of degree of modification
The degree of modification method of SDS-PAGE electrophoresis separation determination modification casein and lactalbumin
Sample treatment: with the sample before and after the modification (milk powder added ultra-pure water by 1: 7 earlier and dissolves) centrifugation degreasing (7200r/min) respectively, the sample determination volume (V after the degreasing
1), solution dilution suitable multiple (100-200 is doubly) adopts the Lowry method to measure soluble protein (X
1).Then sample is adopted the ultra-pure water dialysis, the bag filter molecular cut off is 10000, behind the 24h, and centrifugation (7200r/min), supernatant is measured volume (V
2), after the solution dilution suitable multiple (about 100 times), adopt the Lowry method to measure total soluble protein matter (X
2), adopt conventional PAGE electrophoretic determination protein to form then.With concentration be 10% separation gel and concentration be 3% concentrated glue as discontinuous gel systems, adopt the pH8.3Tris-glycine solution as the buffer electrode liquid system, protein sample concentration is 0.2-4mg/ml, the sample applied sample amount is 4 μ l-10 μ l.On scanning densitometer, electrophoretic band scanned and by the shared percentage composition (M) of integral and calculating testing protein, degree of modification is calculated as follows.
Promptly
Testing protein content * 100% before degree of modification %=(before the modification-modification after) testing protein content/modification
Beneficial effect of the present invention: adopt immobilization complex enzyme coupled ion regulation protein structure and heat treated, make α
sThe peptide chain of-casein and beta lactoglobulin launches, and easily by enzyme hydrolysis, improves the enzyme hydrolysis degree of protein, and the selectivity of enzyme hydrolysis is increased.Do not need the casein in the lactoprotein is separated with lactalbumin, under the enzyme hydrolysis condition of " one-step method ", to casein and lactalbumin generation hydrolysis, make α simultaneously
sThe degree of modification of-casein and beta lactoglobulin reaches 50%~95%, and does not have the bitter taste generation, and process route shortens greatly, has realized suitability for industrialized production.
Eliminate the sensitization of beta lactoglobulin and ALA is all reclaimed with the enzyme process selective hydrolysis, broken through the limitation that forefathers adopt salting out method to separate in this field on the technology.The rate of recovery of existing ALA is up to 85% in the world, and the ALA rate of recovery 100% of the present invention.
With immobilized enzyme hydrolysis external enzyme can be removed fully by filtering, prevent from lactoprotein, to introduce exogenous M-band matter, solved food safety question.And do not need by the heating enzyme that goes out, get rid of the influence of heating, energy savings, the quality of dairy products height of being produced proteinaceous nutrient and functional character.Filtering the immobilization complex enzyme of collecting can be used more than 20 times repeatedly.
Lactoprotein behind the immobilization complex enzyme for hydrolyzing, α
s-casein and beta lactoglobulin are hydrolyzed to relative molecular mass and are lower than 3000 micromolecule polypeptide, digestibility is increased greatly with anaphylaxis to be eliminated, and micromolecule polypeptide has many good health-care effects and nutritive value to human body, is suitable for 0~6 month consumption by infants and indigestion person or designed for old people.
Use this enzyme modification skimmed milk, add whey powder or soybean protein in the skimmed milk, lactalbumin after the processing and caseic ratio can reach the albumen that is similar to human milk and form, digestibility is high and sensitization is low, be applied to the dairy products that ewborn infant laboratory milk and the elderly or indigestion person are suitable for, the dairy products of being produced have no bitter taste, no sensitization, digest and assimilate, are of high nutritive value, raciness, easy high characteristics of quality such as dissolving, and product has good market prospects.China has 2,000 ten thousand neonates to be born present every year, there is 30% baby to need artificial suckling approximately, though breast milk is the optimal food of baby forever, but under the situation that does not have breast or hypogalactia, infant formula is particularly important, by China infant number and amount, then need about 150,000 tons every year.But 50,000 tons of present domestic infant formula less thaies can not be met the need of market far away.China is entering astogeny society simultaneously, and the elderly and patient account for 1/3.Therefore, these dairy products have very high economic benefit and social benefit.
The specific embodiment
Embodiment 1
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets.Skimmed milk is regulated and heat treated through ion: with 1~2: 1~2: 1 ratio Ca
2+, K
+And Na
+Solution is regulated ion concentration, makes pH reach 7.0~7.5; Protein concentration is 3.1% in the solution, is warming up to 70-90 ℃ by heat exchanger heats, keeps 5-15s, is cooled to 45-65 ℃ then.The immobilization complex enzyme zymohydrolysis: enzyme is papain and trypsase, two kinds of enzyme ratios are 4: 6, carrier is a sodium alginate, sodium alginate soln concentration is 5%, enzyme/carrier mass ratio is 1: 25, drip glutaraldehyde and make that glutaraldehyde concentration is 0.6% in the solution, at 35 ℃ of following stirring reaction 10h, being fixed complex enzyme.Enzymatic hydrolysis condition is: enzyme dosage is 1 ‰, 55 ℃ of enzymolysis 2.5h of lactoprotein quality, α
sThe degree of modification of-casein and beta lactoglobulin reaches 85%, 95% respectively.Again by removing by filter the immobilization complex enzyme.Filtering the immobilization complex enzyme of collecting can be used more than 20 times repeatedly.
Embodiment 2
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets.Add desalted whey powder in the skimmed milk, addition is 5% mass/volume ratio, regulates and heat treated through ion: with 1~2: 1~2: 1 ratio Ca
2+, K
+And Na
+Solution is regulated ion concentration, makes pH reach 7.0~7.5; Protein concentration is about 3.7% in the solution, is warming up to 70-90 ℃ by heat exchanger heats, keeps 5-15s, is cooled to 45-65 ℃ then.The immobilization complex enzyme zymohydrolysis: enzyme is papain and pepsin, two kinds of enzyme ratios are 5: 5, carrier is a shitosan, chitosan solution concentration is 3.5%, shitosan should be with the acetum dissolving of 1%-2%, after 6mol/L NaOH transfers pH to 7.5, drain and with the washing of the phosphate buffer of pH7.5, and then adding enzyme liquid, stirring and adsorbing 30-40min, enzyme/carrier mass ratio is 1: 50, drips glutaraldehyde and makes that glutaraldehyde concentration is 0.8% in the solution, at 25 ℃ of following stirring reaction 7h, being fixed complex enzyme.Enzymatic hydrolysis condition is: enzyme dosage is 0.5 ‰, 45 ℃ of enzymolysis 1h of lactoprotein quality, α
sThe degree of modification of-casein and beta lactoglobulin is respectively 75%, 87%.By removing by filter the immobilization complex enzyme.
Embodiment 3
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets.Add desalted whey powder in the skimmed milk, addition is 10% mass/volume ratio, regulates and heat treated through ion: with 1~2: 1~2: 1 ratio Ca
2+, K
+And Na
+Solution is regulated ion concentration, makes pH reach 7.0~7.5; Protein concentration is about 4.4% in the solution, is warming up to 70-90 ℃ by heat exchanger heats, keeps 5-15s, is cooled to 45-65 ℃ then.The immobilization complex enzyme zymohydrolysis: enzyme is papain and bromelain, two kinds of enzyme ratios are 6: 4, carrier is an alginate, the alginate solution concentration is 2% (sodium alginate concentration is 1%, chitosan concentration be 1%), enzyme/carrier mass ratio is 1: 10, drip glutaraldehyde and make that glutaraldehyde concentration is 0.3% in the solution, at 10 ℃ of following stirring reaction 5h, being fixed complex enzyme.Enzymatic hydrolysis condition is: enzyme dosage is 0.2 ‰, 65 ℃ of enzymolysis 4h of lactoprotein quality, α
sThe degree of modification difference 75%, 85% of-casein and beta lactoglobulin.By removing by filter the immobilization complex enzyme.
Embodiment 4
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets.Skimmed milk is regulated and heat treated through ion: with 1~2: 1~2: 1 ratio Ca
2+, K
+And Na
+Solution is regulated ion concentration, makes pH reach 7.0~7.5; Protein concentration is 3.1% in the solution, is warming up to 70-90 ℃ by heat exchanger heats, keeps 5-15s, is cooled to 45-65 ℃ then.The immobilization complex enzyme zymohydrolysis: enzyme is pepsin and bromelain, two kinds of enzyme ratios are 4: 6, carrier is a sodium alginate, sodium alginate soln concentration is 5%, enzyme/carrier mass ratio is 1: 10, drip glutaraldehyde and make that glutaraldehyde concentration is 0.6% in the solution, at 35 ℃ of following stirring reaction 10h, being fixed complex enzyme.Enzymatic hydrolysis condition is: enzyme dosage is 1 ‰, 40 ℃ of enzymolysis 1h of lactoprotein quality, α
sThe degree of modification of-casein and beta lactoglobulin is respectively 75%, 88%.By removing by filter the immobilization complex enzyme.
Embodiment 5
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets.Add soybean protein in the skimmed milk, addition is 3% mass/volume ratio, regulates and heat treated through ion: with 1~2: 1~2: 1 ratio Ca
2+, K
+And Na
+Solution is regulated ion concentration, makes pH reach 7.0~7.5; Protein concentration is about 5% in the solution, is warming up to 70-90 ℃ by heat exchanger heats, keeps 5-15s, is cooled to 45-65 ℃ then.The immobilization complex enzyme zymohydrolysis: enzyme is bromelain and trypsase, two kinds of enzyme ratios are 5: 5, carrier is a shitosan, chitosan solution concentration is 3.5%, shitosan should be with the acetum dissolving of 1%-2%, after 6mol/L NaOH transfers pH to 7.5, drain and with the washing of the phosphate buffer of pH7.5, and then adding enzyme liquid, stirring and adsorbing 30-40min, enzyme/carrier mass ratio is 1: 25, drips glutaraldehyde and makes that glutaraldehyde concentration is 0.8% in the solution, at 20 ℃ of following stirring reaction 7h, being fixed complex enzyme.Enzymatic hydrolysis condition is: enzyme dosage is 0.5 ‰, 55 ℃ of enzymolysis 2.5h of lactoprotein quality, α
sThe degree of modification of-casein and beta lactoglobulin is respectively 82%, 95%.By removing by filter the immobilization complex enzyme.
Embodiment 6
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets.Add soybean protein in the skimmed milk, addition is 10% mass/volume ratio, regulates and heat treated through ion: with 1~2: 1~2: 1 ratio Ca
2+, K
+And Na
+Solution is regulated ion concentration, makes pH reach 7.0~7.5; Protein concentration is about 10% in the solution, is warming up to 70-90 ℃ by heat exchanger heats, keeps 5-15s, is cooled to 45-65 ℃ then.The immobilization complex enzyme zymohydrolysis: enzyme is pepsin and trypsase, two kinds of enzyme ratios are 6: 4, carrier is an alginate, the alginate solution concentration is 2% (sodium alginate concentration is 1%, chitosan concentration be 1%), enzyme/carrier mass ratio is 1: 50, drip glutaraldehyde and make that glutaraldehyde concentration is 0.3% in the solution, at 10 ℃ of following stirring reaction 5h, being fixed complex enzyme.Enzymatic hydrolysis condition is: enzyme dosage is 0.2 ‰, 65 ℃ of enzymolysis 4h of lactoprotein quality, α
sThe degree of modification of-casein and beta lactoglobulin reaches 72%, 87%.By removing by filter the immobilization complex enzyme.
Embodiment 7
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets, and adds desalted whey powder in the skimmed milk, and addition is 15% mass/volume ratio, carries out enzymolysis processing.All the other operations are with embodiment 1.Return in the milk protein solution after the hydrolysis that removes the immobilization complex enzyme and add the cream that preceding road is separated; again according to the nutritional labeling requirement of human milk; add other compositions; by the 1000ml skimmed milk; add vegetable oil 60g; lactose 29g; B B-complex 1.2g; composite trace element 0.5g and physiological activator such as immunoglobulin (Ig) 0.4g; lactoferrin 0.2g; lysozyme 0.15g; nucleotides 0.06g; choline 0.15g; taurine 0.15g etc. are through the prescription reorganization; and carry out homogeneous; concentrate; spray-drying makes infant formula, and wherein immunoglobulin (Ig) and lysozyme are packed separately and cooperated with milk powder.Every 100g milk powder, control protein 12-18g, fatty 25-31g.
Embodiment 8
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets, and adds desalted whey powder in the skimmed milk, and addition is 7% mass/volume ratio, carries out enzymolysis processing.All the other operations are with embodiment 7.
Embodiment 9
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets, and adds soybean protein in the skimmed milk, and addition is 5% mass/volume ratio, carries out enzymolysis processing.All the other operations are with embodiment 1.Return in the milk protein solution after the hydrolysis that removes the immobilization complex enzyme and add the cream that preceding road is separated, again through the prescription reorganization, and carry out homogeneous, concentrate, spray-drying makes the elderly's prescription emulsifiable powder.Other additive additions are by the 1000ml skimmed milk: maltodextrin 60g, oligoisomaltose 20g, vitamin A 14mg, vitamin D
322 μ g, vitamin E 28mg, vitamin C 84mg, calcium activated 1000mg, ferrous gluconate 120mg, zinc gluconate 65mg.Every 100g milk powder, control protein 20-26g, fatty 10-16g.
Embodiment 10
Fresh milk separates with centrifuge removes the fatty skimmed milk that gets, and adds soybean protein in the skimmed milk, and addition is 8% mass/volume ratio, carries out enzymolysis processing.All the other operations are with embodiment 9.