RU1790756C - Method for assaying food products for histamine - Google Patents

Abstract

Usage: food industry, food hygiene, quality control M. by ce 9, Nva products. SUMMARY OF THE INVENTION: The analyte is extracted with ethanol. The histamine fluorophore is stabilized by adding 0.3 ml of 6 N HCI to the extract in parallel in the experimental and control samples. In a control sample, histamine is preliminarily destroyed by incubation with 0.2 ml of a 0.01 M solution of iodine in water for 8-12 minutes. Concentration was carried out with 0-phthalaldehyde. The concentration of histamine X is determined by the formula X / y - b /: a, where y is the fluorescence intensity of the experimental sample at λ 440 nm, b is the fluorescence intensity of the control sample, and a is the slope of the calibration graph. 1 tab. 1 ave. With C

Description

The invention relates to the field of food hygiene, and concerns the control of products, in particular the content of biologically active substances in them.

A known method for determining histamine in foods is based on a fluorescence measurement of the condensation product of an amine with fluorogen (0-phthalaldehyde). Fluorescence is recorded using synchronous spectra and their derivatives, which requires an additional time of 15-20 minutes for each analysis.

The purpose of the invention is to increase the sensitivity of the method, reducing research time.

The goal is achieved by the fact that histamine ethanol is extracted. The stabilization of histamine fluoroform is carried out in parallel in the experimental and control samples by adding 0.3 ml of 6 N each. hydrochloric acid solution, while in the control sample histamine is preliminarily destroyed by incubation with 0.2 ml of a 0.01 M solution of iodine in water for 8-12 minutes, and the concentration of histamine is determined by the formula

x (y - b): a,

where x is the concentration of histamine,

y is the magnitude of the fluorescence intensity of the control sample,

and - the value of the slope of the calibration graph.

The method is carried out as follows.

Preparation of histamine extract. 2 g of the analyzed material is triturated in

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porcelain mortar with glass powder, gradually added 20 ml of ethanol. The homogenate is transferred to a test tube with a capacity of 50 - 70 ml with ground grinding. Histamine extraction was carried out in a water bath at 60 ° C for 15 minutes. Then the tube is cooled to room temperature, the homogenate is filtered through a paper filter. 1 ml of the filtrate (histamine extract) was transferred to a 100 ml volumetric flask and the volume was adjusted to the mark with ethanol.

To determine histamine from a flask, 1 ml of solution was taken in two tubes. 0.2 ml of a 0.01 M solution of iodine is added to one tube (single sample), and 0.2 ml of double-distilled water is added to the other (experimental sample) and mixed well. After 8 minutes, 0.3 ml of NaOH and 0.35 ml of a 2% aqueous solution of RPA were added to both tubes, each well well mixed, and after 5 minutes 0.3 ml of 6H.HCI.

Histamine fluorophore fluorescence is measured at an excitation wavelength of 360 nm and an emission of 440 nm.,

When calculating the histamine content, a calibration curve is used that reflects the fluorescence intensity (f) of the condensation product of the histamine standard with 0-phthalic aldehyde as a function of the concentration of amine in the sample.

The calibration graph is described by the regression equation

x (y-b): a, where x is the concentration of histamine;

y is the magnitude of the fluorescence intensity of the experimental sample;

a is the value of the tangent of the angle of inclination;

b is the fluorescence intensity of the sample at x 0 (control sample);

This equation allows the histamine content in the sample to be calculated from the magnitude of the fluorescence intensity of the sample.

Example. The fluorescence intensity of the experimental sample (f OD) - 104.7 relates, units; the fluorescence intensity of a blank sample - (f CP) 45.1 rel.

1ph OD - 1ph HP 104.7 - 45.1 59.6 (rel. Units).

The histamine content in the sample is calculated by the regression equation specifically x (y - 9.5); 825.3

x

59.6-9.5 825.3

0.0607 (μg / ml).

Given a dilution factor of sample 1000, the histamine content of the analyzed material is 6.07 mg / 100 g.

The positive effect consists in increasing the sensitivity of the method by 1.5-1.6 times and reducing the research time by 1/3 (80 - 90 and 50 - 60 minutes, respectively).

The table shows the characteristics of the fluorescent method for the determination of histamine in food products.

Claims (1)

The claims A method for the determination of histamine in food products, including extraction of the analyzed material with alcohol, condensation with 0-phthalaldehyde in an alkaline medium, stabilization of the obtained fluorophore with histamine acid, dilution with alcohol to a concentration of histamine corresponding to the standard concentration range on the calibration graph, measuring the fluorescence intensity, different the fact that, in order to increase the sensitivity of the method, alcohol is used for extraction as an alcohol ethanol, stabilization of histamine fluorophore is carried out in parallel in the experimental and control samples by adding 0.3 ml of 6 N each. HCI, in this case, in the control sample, histamine is preliminarily destroyed by incubation with 0.2 ml of a 0.01 M solution of iodine in water for 8-12 minutes, and the concentration of histamine is determined by the formula x (y - b): a, where x - concentration of histamine; y is the magnitude of the fluorescence intensity of the experimental sample at 440 nm; b is the magnitude of the fluorescence intensity of the control sample; and - the value of the slope of the calibration graph.