SU1722383A1 - Process for separating proteins from milk whey - Google Patents

Abstract

The invention relates to biotechnology, relates to a method of electrocontact separation of residual protein from whey and can be used in the dairy industry. The purpose of the invention is to reduce the cost of the method by reducing the specific energy consumption. To achieve the goal, residual whey protein is coagulated in the cathode chamber of a diaphragm electrolyzer at a cathode current density of 0.002-0.1 A / cm2. The resulting suspension is divided in a field of mass forces into a protein mass and a clarified serum, which is filled with an anode chamber. A new feature in the method is the establishment of a lower limit of pH (6.51 + 0.05) - 0.005 (T ° C - 25), at which saturation of the process of coagulation of proteins and their aggrega- tive stability are observed, where T & C is the temperature range of 20-45 ° C. While maintaining this mode, the specific energy consumption for the release of residual whey protein is reduced. 1 ill., 1 tab. and C

Description

The invention relates to biotechnology and the food industry, in particular to methods for extracting residual protein from whey.

It is known to extract protein components as a result of their electrocontact coagulation in the anode chamber of a diaphragm electrolyzer at an anode current density of 0.05-0.3 A / cm2.

However, the increased acidity of the final product and its contamination with the products of electrochemical reactions at the anode reduce its consumer value.

There is also known a method for isolating residual protein from whey in the cathode chamber of a diaphragm electrolyzer at 60 ° C and a flow density of 0.002-0.1 A / cm2, according to which the anodic chamber is filled with clarified whey with a pH of 7.0-7.5 after separation. from it coagulated protein.

The disadvantage of this method is a high degree of alkalization (pH 4.5), which lowers the use value of the product and requires increased energy costs.

The purpose of the invention is to reduce the cost of the method by reducing the specific energy consumption.

For this, in a known method of extracting residual protein from whey by passing through it a constant electric current of density 0.002-0.1 A / cm2 in the cathode chamber of the diaphragm electrolyzer, further separating the aggregated protein mass from the clarified whey and filling the anode chamber with it to achieve one

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For the intended purpose, the process is carried out with a minimum sufficient degree of alkalization of the medium, the pH of which should be at least (6.51 + 0.05) - 0.005 (), for the temperature range of 20-45 and C. The electrocoagulation process is carried out in the temperature range of 20 (serum temperature coming from production) 45 ° С, in which the probability of conformational changes leading to the loss of the biological value of the protein is excluded. Therefore, in view of the temperature dependence of the active acidity, the experimentally determined temperature correction 0.005 (T ° C-25 °), where 0.005 DRN AT ° C 1, is introduced into the pH value (6.51 + 0.05).

The proposed method of extracting residual protein from whey is implemented as follows.

Whey with an initial pH of 4.5 is passed through the cathode chamber of the diaphragm electrolyzer. Clarified treated serum enters the anode chamber. The process is carried out at a constant current density at the cathode of 0.015 A / cm2 and a constant temperature of 25 ° C. During electrolysis, protein coagulation occurs due to a combination of factors (direct electrolysis of hydration shells, interaction at the boundary with a gas bubble, gradients and concentration of hydroxyl ions, etc.). Coagulated from the resulting liquid-Lena heterophase system, after stirring, is separated in the field. mass forces, and the supernatant analyzed spectrophotometrically. The data obtained were processed by the linear regression method for the broken dependency.

The drawing is a graphical interpretation of the calculated (solid line) and experimental (asterisk) results.

According to the graph, the coagulation process starts at a pH of 6.2 and goes into a saturation stage at a pH of 6.51 (the tg angle of inclination of the third linear section is 0.003067). Thus, for the formation of an aggregate-stable dispersed phase, allowing separation from the dispersed medium in the field of mass forces, it is sufficient that the pH of the medium exceed only 6.51-0.05. To do this, it is necessary to pass less electricity through the cell than to achieve a pH of 7.0-7.5.

A comparative analysis of the invention with the prototype shows that the proposed method differs from the well-known one in that, in order to achieve the same degree of extraction of residual protein, the pH of the medium must exceed, in general, only the values of 6.51+

0.05 (0.05. - accuracy of the device pH-340). Thus, to isolate the same amount of protein mass (as will be shown), it is necessary to conduct electrolysis.

less water from whey, and therefore it is necessary (according to Farad’s law) to pass less electricity through the cell. This means that the specific energy consumption (the cost per unit mass of the isolated protein) is less.

The allocation of approximately equal amounts of protein at pH. 6.51 and more up to a denaturation pH of 11.2 explained

5 by the nature of the dissociation of the surface amine and carboxyl groups of proteins, which depends on the active acidity of the medium. It is known that maximally dissociated groups create around

0 most dense hydration shells that prevent coagulation.

 To resolve the inconsistencies associated with this, alkalization, in this case electrolytic, is proposed in such

5 degrees so that the products of electrolysis neutralize part of the dissociated groups, but do not deviate strongly from the pH of the iso-electric, i.e. until a pH of 6.50-6.51 prevails. A further increase in pH modifies the process, since the departure from pHizd. compresses common hydrated shells.

The drawing shows the dependence of the degree of protein recovery in the supernatant from the active acidity of the medium,

5 modified in the process of electrolysis of whey in the cathode chamber of the diaphragm electrolyzer. The degree of extraction was determined spectrophotometrically based on the change in the optical density of the clarified serum at the wavelength. 278 nm. The optical density analysis in the visible range of light is not correct, since whey protein is in a dissolved state (the solution is clear if casein dust is separated) and absorbs light only in the ultraviolet region (for example, 278 nm).

The method is illustrated by an example. The process is carried out with the following parameters: 5 meters: cathode area 200 cm2; the current was stabilized at J for (ie, 0.015 A / cm, which corresponds to the modes of the prototype); flow through the cathode chamber P 500 ml / h.

0 The results of protein isolation are listed in the table.

Based on the data in the table, as well as the graph, it can be noted that the degree of protein secretion reaches a limiting value at pH 6.51-6.52.

Treatment of serum at pH 7 by a known method requires an additional 15 minutes of treatment, on which it is necessary to expend work equal to W

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The method was also carried out at 20, 30, 35, 40, 45 (° C). The dependences D (pH), similar in character to the dependence given in the drawing, and differing only in the value of the active acidity of the medium, which changes by -0.005 at AT 1 ° C, i.e. The desired pH value is (6.51 + 0.05) -0.005 (T ° C-25 °).

The use of the proposed method of extracting residual protein from whey provides in comparison with the known ones: a decrease in the degree of alkalization of the medium in the cathode chamber, which leads to energy savings and, moreover, to a lower probability of conformational changes of proteins, and this helps to preserve them. biological value. In addition, with the same energy costs as in similar methods, it is possible to process a larger volume of whey or to obtain a larger amount of the final product.

In general, cnocofi allows to reduce the specific energy consumption.

Claims (1)

Invention Formula A method for isolating proteins from whey by passing a direct current through it in the cathode chamber of a diaphragm electrolyzer at a current density of 0.002-0.1 A / cm2 at the cathode, followed by separating the resulting suspension into a protein mass and clarified whey and returning the latter to the anode chamber of the electrolyzer, characterized in that, in order to reduce the cost of the process, calculating the specific energy consumption, electrical treatment is carried out at a pH of (6.51 0.05) - 0.005 (T ° C-25 °) and a temperature of 20- 45 ° C. 2 s  t L J L L O) L About About SG Cl "- 3 in 1OSHO OJ FC1 ); m gg-, sifa YuYuYuYuL “From the Scruff” yuyuche Sch) -kve letngpFllsllslgpa. OIO) OFO O O 06O FFO SPS | 1O SLS- iOiO “3 t-13 h 3S С-J3 О -“) t-- CCRlO e oe e e “1O qi .. ,,,, .. ,,,. CS S3tSS StSKS (SCS SlSIS) tS51lSlStS} S5} S C tS) Editor M.Kelemes Compiled by GA Osilov Tehred M. Morgenth oOFs gaO1 sf o SL O S -O ae ODJ5 D J5 D OO S O1O 93S1O1 (71 ( about yoo - l-lke - " o see oe rs u o o o chg About "E CM NM - -3 O SP  with chg v y. Proofreader O. Shevkun