CN106720346B

CN106720346B - Method for improving stability of high-calcium milk by optimizing production process

Info

Publication number: CN106720346B
Application number: CN201610640886.5A
Authority: CN
Inventors: 周鹏; 胡锦华; 刘晓勇; 陆计萍; 张捷
Original assignee: Shandong Haizhibao Seafood Co ltd; Jiangnan University
Current assignee: Shandong Haizhibao Seafood Co ltd; Jiangnan University
Priority date: 2016-08-08
Filing date: 2016-08-08
Publication date: 2020-06-09
Anticipated expiration: 2036-08-08
Also published as: CN106720346A

Abstract

The invention discloses a method for improving the stability of high-calcium milk by optimizing a production process. Raw milk (including fresh milk, liquid finished milk, milk protein concentrated solution, milk powder or milk protein concentrated powder and other protein dry powder redissolves) effectively improves the dispersion stability of inorganic calcium salt type calcium reinforcing agents in products through the feeding sequence of the calcium reinforcing agents (such as calcium carbonate, calcium phosphate, hydroxyapatite and the like) and thickening stabilizing agents (such as sodium carboxymethylcellulose, chitosan, carrageenan and the like) in the raw milk. The method has the advantages of simple operation and realization by only adjusting the charging sequence. The prepared high-calcium milk powder with enhanced stability can also be used for the production of various high-calcium protein products.

Description

Method for improving stability of high-calcium milk by optimizing production process

Technical Field

The invention relates to a method for improving the stability of high-calcium milk by optimizing a production process, and belongs to the field of milk powder processing.

Background

Calcium is an important mineral element in human body, and if the calcium is not taken sufficiently for a long time, the health of human body is affected. Due to the differences between the human body and dietary structure, in many cases, the requirement of the body for calcium cannot be met well only by obtaining calcium from food. The high-calcium food added with the calcium nutrition enhancer is one of effective ways for solving the problem of insufficient calcium intake. At present, calcium enhanced milk and dairy products are popular in the market due to good nutritional functionality, but still have some problems of shelf-life stability.

The common calcium nutrition enhancer comprises organic calcium salts such as calcium lactate and calcium gluconate and inorganic calcium salts such as calcium carbonate and tricalcium phosphate, wherein the organic calcium salts have good solubility and can affect the thermal stability of dairy products to cause problems of milk precipitation and the like, because α s-and β -casein which is rich in phosphoserine groups in milk is very sensitive to calcium ions and is easily combined with the calcium ions, the surface charge of casein micelles is reduced, the space stabilizing effect is weakened, the electrostatic repulsion between double electric layers of stable colloid particles is partially shielded, the calcium ions can be combined with phosphoserine residues to cause bridging flocculation between the casein micelles, and the effects all affect the stability of the dairy products.

In actual production, the insoluble inorganic calcium salt is in the form of micronized calcium powder particles which are directly mixed with the dairy product, and the calcium salt particles are dispersed in the milk protein solution in a free-settling state all the time. Essentially, this dispersion is a thermodynamically unstable system, in which the calcium salt particles are subjected to gravitational and diffusive forces. On the one hand, when the density of the calcium salt particles is greater than that of the milk protein solution, the calcium salt particles settle due to gravity; under quiescent conditions, sub-micron particles will follow Stokes law with settling velocities related to particle density, diameter, and media viscosity. On the other hand, the particles with different particle sizes in the dispersion system all undergo random brownian motion, the diffusion force can enable the particles to be distributed in a dispersion manner in the medium, but meanwhile, the disordered collision of the molecular thermal motion causes the collision among the particles, so that the particles are easy to agglomerate, and the smaller the particle size, the larger the surface area, the higher the surface energy, and the more the particles are easy to generate spontaneous agglomeration. Therefore, the dispersion stability of inorganic calcium salts in liquid dairy products is relatively poor.

Disclosure of Invention

Aiming at the problem that the dispersion stability of the indissolvable inorganic calcium salt in the liquid dairy product is relatively poor, the invention optimizes the production through a simple process, mainly adjusts the feeding sequence of the calcium reinforcing agent and the thickening stabilizer, namely improves the stability of the inorganic calcium salt by driving layer-by-layer self-assembly through electrostatic interaction to form a polysaccharide/protein double-shell layer. The method is simple and convenient in process, high in operability and very suitable for industrial production.

In order to achieve the aim, the technical scheme adopted by the invention is that the calcium reinforcing agent is firstly added into the liquid milk for premixing reaction for a certain time, and then the thickening stabilizing agent is added, so that the good effect of improving the stability of the high-calcium liquid milk can be achieved.

The specific process comprises the following steps:

(1) the calcium reinforcing agent is added into the raw milk firstly, and the raw milk is fully mixed and stirred uniformly.

(2) Adding thickening stabilizer into the mixture of the raw milk and the calcium enhancer.

(3) Processing the raw milk according to a normal process.

(4) The liquid milk is directly packaged into finished products or is spray dried to obtain the high-calcium milk powder.

(5) The high calcium milk powder obtained by spray drying can also be added into other products, so that the correlation of the products is improved.

The raw milk comprises fresh milk of various milk sources such as cow milk, buffalo milk, yak milk, goat milk, sheep milk, horse milk, donkey milk, camel milk and the like, liquid finished milk, milk protein concentrated solution, milk powder or milk protein concentrated powder and other protein dry powder redissolved matters.

The calcium enhancing agent includes various inorganic calcium salts such as calcium carbonate, calcium phosphate, hydroxyapatite, etc.

The thickening stabilizer comprises various polysaccharides such as sodium carboxymethylcellulose, chitosan, carrageenan and the like.

The high-calcium milk powder can be used for producing various high-calcium protein products.

The beneficial effects of adopting the above technical scheme are that: the pre-combination of the calcium enhancer and the thickening stabilizer reduces the dispersion stability of the inorganic calcium salt in the aqueous solution. The stability of the high-calcium liquid milk can be improved by adding the thickening stabilizing agent after the calcium reinforcing agent is added into the liquid milk for pre-reaction for a certain time. The principle of enhancing the stability of the high-calcium liquid milk by improving the process sequence is that in the processing process, a protein layer and a polysaccharide layer are sequentially adsorbed on the surface of the inorganic calcium salt, and a polysaccharide/protein double-shell layer is formed by layer-by-layer self-assembly driven by electrostatic interaction, so that the dispersion stability of the inorganic calcium salt in a solution system is improved. The invention provides a solution with simple operation and high practicability for improving the stability of the high-calcium dairy product from the aspect of adjusting the processing technology.

Drawings

FIG. 1 is a graph of the absorbance of the redispersed suspension of the complex (HA-SC-CMC I) as a function of time.

Figure 2 effect of different addition sequences on the stability of high calcium liquid milk after 30 minutes (a) i.ha + ii.sc + iii.cmc I; (B) ha + ii.cmc I + iii.sc.

FIG. 3 is a confocal laser imaging of isolated complex particles after adding CMC covalently labeled with FITC to HA-SC.

FIG. 4 shows the mechanism of improving the stability of high calcium milk by optimizing the production process.

FIG. 5 plot of absorbance versus time for redispersed suspensions of complex (HA-SC-CMC II).

FIG. 6 plot of absorbance versus time for redispersed suspensions of complex (HA-SC-CMC III).

The specific implementation mode is as follows:

the present invention will be described in further detail with reference to specific examples, but is not limited to the following examples.

Example 1

A method for preparing polysaccharide-protein-calcium salt compound by taking sodium caseinate, hydroxyapatite and sodium carboxymethylcellulose as raw materials to improve the dispersion stability of the hydroxyapatite comprises the following specific process steps:

weighing 20mg of HA-SC compound, adding a small amount of ultrapure water to uniformly disperse the HA-SC compound, adding a CMC solution to ensure that 0.2 mg-15.0 mg of CMC I (with the molecular weight of 250,000 and the substitution degree of 0.9) in a final 10mL reaction system is uniformly mixed, adjusting the pH to 4.0 by hydrochloric acid, carrying out rotary culture for 4h, centrifuging at 4000rpm for 10min, re-dispersing the precipitate in 10mL of ultrapure water, oscillating, centrifuging at 4000rpm for 10min again, and obtaining the precipitate, namely the washed HA-SC-CMC I compound. With the increase of the addition amount of the CMC, the HA-SC surface adsorbs more CMC, the surface HAs more negative charges, the electrostatic repulsion effect among particles and the steric hindrance effect of CMC polysaccharide chains are enhanced, and thus the stability of the HA-SC-CMC I compound redispersion suspension is improved (figures 1 to 4).

Example 2

Weighing 20mg of the HA-SC compound, adding a small amount of ultrapure water to uniformly disperse the HA-SC compound, adding a CMC solution to ensure that the CMC II (with the molecular weight of 700,000 and the degree of substitution of 0.9) in a final 10mL reaction system is 0.2 mg-15.0 mg, and finally obtaining the HA-SC-CMC II compound by the same concrete operation steps as the embodiment 1. With the increase of the addition amount of CMC, more CMC II is adsorbed on the surface of HA-SC, the surface HAs more negative charges, the electrostatic repulsion effect among particles and the steric hindrance effect of polysaccharide chains are enhanced, so that the stability of the HA-SC-CMC II compound redispersed suspension is improved (figure 5).

Embodiment 3

Weighing 20mg of the HA-SC compound, adding a small amount of ultrapure water to uniformly disperse the HA-SC compound, adding a CMC solution to ensure that the CMC II (with the molecular weight of 250,000 and the degree of substitution of 0.7) in a final 10mL reaction system is 0.2 mg-15.0 mg, and finally obtaining the HA-SC-CMC III compound by the same concrete operation steps as the embodiment 1. As the addition amount of CMC is increased, more CMC is adsorbed on the surface of HA-SC, the surface of HA-SC-CMC III complex HAs more negative charges, and the stability of the redispersed suspension of the HA-SC-CMC III complex is improved (figure 6).

Claims

1. A method for improving the stability of high-calcium milk by optimizing a production process is characterized by comprising the following specific process steps:

(1) firstly, adding a calcium reinforcing agent into raw milk, fully mixing and uniformly stirring; the calcium reinforcing agent comprises various inorganic calcium salts, wherein the inorganic calcium salts comprise calcium carbonate, calcium phosphate or hydroxyapatite;

(2) adding a polysaccharide thickening stabilizer into a mixture of raw milk and a calcium reinforcing agent to form a polysaccharide/protein double-shell layer on the surface of inorganic salt;

(3) processing the raw milk according to a normal process;

(4) directly packaging the liquid milk into a finished product or spray drying to obtain high-calcium milk powder;

(5) the high calcium milk powder obtained by spray drying can also be added into other products to improve the related performance of the products.

2. The raw milk of claim 1 comprising cow's milk, buffalo's milk, yak's milk, goat's milk, sheep's milk, horse's milk, donkey's milk and camel's milk.

3. The raw milk of claim 1 comprising fresh milk, liquid finished milk, milk protein concentrate, milk powder or milk protein concentrate powder.

4. The thickening stabilizer of claim 1, comprising various polysaccharides including sodium carboxymethylcellulose, chitosan, and carrageenan.

5. The high calcium milk powder of claim 1 can be used for the production of various high calcium protein products.