RU2526187C1 - Method for determination of gluten quantity in wheat flour - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: method envisages flour sampling and the samples placement in a capacity sensor. The samples are heated up to +70°C. The flour dielectric permeability is measured at such temperature. Gluten quantity is determined from the formula: η=a₁·ε+a₀, where η - gluten quantity in wheat flour, %; ε - dielectric permeability of flour sample; a₁ and a₀ - beta coefficients.

EFFECT: invention allows to reduce the time of measurement of gluten quantity in flour and increase accuracy of gluten determination during instrumental invention implementation.

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Description

The present invention relates to physical methods for analyzing the amount of gluten in flour and can be used by grain producers, grain storage elevators, flour mills, bakeries, laboratories, etc. The technical result is to reduce the time for measuring the amount of gluten in flour and to increase the accuracy of its measurement by the proposed physically justified method, including metrologically evaluated measurement operations in the instrument implementation of the invention.

There is a method of determining the quality of gluten in wheat (RF patent No. 2138042, published September 20, 1999), which consists in measuring the spectral characteristics of wheat samples and then determining the amount of gluten from the values of spectral characteristics, taking into account calibration measurements, providing for the measurement of integrated diffuse transmission intensities in two spectral ranges of 400-600 nm and 600-850 nm, and the amount of gluten is determined by the formula:

, $$C=A\cdot \lg \frac{J_k}{J_0}$$

,

where C is the amount of gluten;

A - calibration coefficient obtained when calibrating the device for samples with known gluten content, determines the gluten content;

J _k is the integrated transmission intensity in the range of 600-850 nm;

J ₀ - the intensity of the integrated transmission in the range of 400-600 nm.

A comparative assessment of the measurement results by the indicated method and the standard method according to GOST 27839-88 is not entirely correct, since it allows determining the gluten content only in the range of 26-28%, and the practically necessary range for measuring the amount of gluten is in the range of 20-32% [1]. The above, as well as the lack of physical substantiation of the essence of the method for determining the gluten content by the value of the integral transmission intensity, does not allow to extrapolate the above equation that implements the proposed method for calculating the amount of gluten in the really necessary range of measuring the amount of gluten 20-32%.

It is also impossible to agree with the statement that the error value of the device that implements this method does not exceed 1.0% of the gluten content, since the calculation of the reduced error of 1.0% was performed when calibrating the device based on measurements of the amount of gluten by the standard method, which allows a discrepancy between analyzes of parallel samples 2.0% (absolute error 2.0%) [2].

The closest analogue in technical essence is a method for determining the amount of gluten in flour, implemented in a method for determining the amount of gluten in flour according to GOST 27839-88 "Wheat flour. Methods for determining the quantity and quality of gluten. " The specified method includes determining the amount of gluten in flour according to the results of washing it from the prepared dough of the analyzed flour.

The analysis includes dosing of water and flour, kneading dough, rolling dough into plates. The plate is placed for a certain time for tracking, then the plate is removed from the water, manually squeezed until a normalized difference between weighings is achieved.

The disadvantage of this method is the significant time spent for analysis, which in manual mode is up to 80 minutes, in mechanized mode - up to 60 minutes. In addition, at each stage of the analysis, an error due to the human factor is introduced. So, for example, with both manual and mechanized methods for determining the amount of gluten, it is prescribed to clean equipment (spatula, pestle, mortar, pins, bowl, etc.) from torn pieces of gluten and attach them to the total mass of laundered gluten.

The present invention is aimed at reducing the time of measuring the amount of gluten in flour and improving the accuracy of its determination in the instrument implementation of the invention.

The problem is solved by the proposed method for determining the amount of gluten in flour, which consists in measuring the dielectric constant of flour at a temperature of + 70 ° C and then determining the amount of gluten from the values of dielectric constant taking into account calibration measurements.

The essence of the proposed method is based on an increase in the dielectric constant of a product (material) containing bound water with an increase in its temperature [3]. In wheat flour with a moisture content of up to 15%, water is firmly bound in the form of a second monomolecular layer, which determines the maximum value of the binding energy of water. At the same time, the amount of gluten protein is the main indicator of moisture absorption, and, therefore, gluten protein and creates the main "competition" of free water binding to the rest of the flour composition at the indicated moisture level, thereby substantiating the presence of a quantitative relationship between gluten and its water [4].

When the flour is heated, part of the bound water goes into a free state and, given that the dielectric constant of free water is higher than the dielectric constant of water, bound with a further increase in the temperature of the flour, gluten will begin to free water. An increase in the amount of free water in the flour leads to an increase in the dielectric constant of the flour, which is measured when the flour temperature reaches + 70 ° C, and the amount of gluten is determined by calibration measurements using the formula (regression equation): η = а ₁ · ε + а ₀ , where η is the amount of gluten in wheat flour,%; ε is the dielectric constant of the flour sample; and ₁ and a ₀ are the coefficients of the regression equation. The graph of the obtained dependence is shown in figure 1.

Thus, the proposed method makes it possible to reduce the analysis time by three times in comparison with the standard method and to eliminate errors caused by subjective factors during the analysis according to the standard method associated with the washing of gluten, which will potentially reduce the error in determining the amount of gluten in the instrument implementation of the proposed method .

Evaluation of the quality of determining the amount of gluten in flour using the above regression equation, carried out according to the Fisher criterion, confirmed the adequacy of the resulting equation.

Information sources

1. GOST R25189-2003. Wheat flour. General specifications.

2. GOST 27839-88. Wheat flour. Methods for determining the quantity and quality of gluten.

3. Dumansky A.V. Lyophilicity of dispersed media. Kiev: Publishing House of the Academy of Sciences of the Ukrainian SSR. - 1960, p. 211.

4. Duckworth R.B. Water in food products (translation from English). M .: Food industry. - 1980, p. 375.

Claims (1)

A method for determining the amount of gluten in wheat flour, involving the sampling of flour, its placement in a capacitive sensor, heating to a temperature of + 70 ° C, measuring its dielectric constant at this temperature, and the amount of gluten is determined by the formula:
η = a ₁ · ε + a ₀ ,
where η is the amount of gluten in wheat flour,%;
ε is the dielectric constant of the flour sample;
and ₁ and a ₀ are the coefficients of the regression equation.

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