RU2733411C1 - Method of producing hydrophobic flavonol and anthocyanic compounds from flavonoid-containing plant material - Google Patents

Abstract

FIELD: medicine; food industry.

SUBSTANCE: invention relates to a method for producing hydrophobic flavonoid antioxidants from flavonoid-containing herbal raw materials and can be used in food, medical, perfume and cosmetic industry. Method of producing hydrophobic flavonol and anthocyan compounds from flavonoid-containing herbal raw materials, in form of pomace of blackcurrant berries, black chokeberry, petals of red flowers, bulb onion husks, which includes raw material drying, grinding, extraction of natural flavonoids with a solution with volume fraction of ethanol of 96 %, separation of pigment extract and concentration, hydrolysis of glycoside forms of natural flavonoids is carried out by adding to the extract pigments concentrated orthophosphoric acid in amount of 4–6 % of dry substances content in extract and hydrolysis of natural flavonoids at temperature of 70–80 °C to constant content of dry substances in composition of extract with subsequent filtering and drying agglomerants precipitated in flavonoids.

EFFECT: method implementation reduces the ethanol hydrolysis process temperature, reduces the hydrolysis reaction time, substitutes the toxic extractant methanol for ethanol permitted for use in the food industry, using hydrophobic flavonol and anthocyan pigments for use in food, medical, perfume and cosmetic industry.

1 cl, 1 tbl, 4 ex

Description

The invention relates to a method for producing hydrophobic flavonoid antioxidants from flavonoid-containing plant materials and can be used for use in food, medical, perfumery and cosmetic industries.

There are various methods of obtaining flavonoid compounds from plant materials (Bolotov V.M. Food colors: Classification, properties, analysis, application / V.M.Bolotov, A.P. Nechaev, L.A. Sarafanova - SPb .: GIORD, 2008 - 240 p.).

The proposed methods make it possible to isolate natural flavonoids (polyphenolic flavonols and anthocyanins) from plant raw materials in the form of water-soluble glycosidic forms, which limits their use as antioxidants for products and materials with hydrophobic properties. Extraction of natural flavonoids, followed by hydrolysis of glycosidic forms, makes it possible to obtain polyphenols in the form of aglycones with hydrophobic properties.

The closest in technical essence and the achieved effect is a method for obtaining anthocyanidins (hydrophobic aglycones of anthocyanin compounds) from natural anthocyanin-containing sources of plant raw materials, which consists in the hydrolysis of the isolated anthocyanins in an aqueous solution of hydrochloric acid of various concentrations when heated (S.S. Tanchev - Moscow: Food prom-t, 1980, p. 8, 13).

The essence of the method lies in the fact that homogenized natural anthocyanin-containing raw materials are treated with chilled or non-chilled methanol or ethanol containing 1% hydrochloric acid. After settling and filtration, the anthocyanin extract is concentrated under vacuum at a temperature of 30-40 ° C, and then used to isolate and separate anthocyanins. Hydrolysis of anthocyanins is carried out in a 2N hydrochloric acid solution at a temperature of 100 ° C for 40 minutes or 6N hydrochloric acid at the same temperature for a shorter time.

The disadvantage of the known method is that for the hydrolysis of anthocyanins, a high temperature is used, which causes the destruction of the anthocyanin molecule, and the concentrated hydrochloric acid used under the process conditions releases hydrogen chloride vapors harmful to health and the environment into the atmosphere. Replacing hydrochloric acid as a catalyst with concentrated orthophosphoric acid allows you to lower the temperature of the hydrolysis process to 70-80 ° C and reduce the destruction of anthocyanin molecules, as well as prevent the release of harmful vapors into the atmosphere. A decrease in the temperature of the hydrolysis reaction allows to reduce the energy consumption of the process and the cost of the finished product.

To solve the technical problem of the invention, a method is proposed for obtaining hydrophobic flavonol and anthocyanin compounds from flavonoid-containing plant raw materials, including drying the plant raw materials, grinding the raw materials, extracting natural flavonoids with a solution with a volume fraction of ethanol 96%, separating the pigment extract and concentrating, characterized in that the process of hydrolysis of glycoside forms of natural flavonoids were carried out by adding concentrated orthophosphoric acid to the pigment extract at a temperature of 70-80 ° C, hydrolysis was carried out to a constant content of dry substances in the extract, followed by filtration and drying of the precipitated flavonoid aglycones.

As a vegetable raw material, it is possible to use pomace of black currant berries, black chokeberry, red petals, onion husks.

Flavonoid aglycones are powders from dark red (for anthocyanidins) to dark brown (for flavonols) color, insoluble in water, readily soluble in lower alcohols (ethanol, isopropyl alcohol), acetone, poorly soluble in esters (ethyl acetate, butyl acetate) and other low-polarity organic solvents.

Aglycones of flavonoids are polyphenolic compounds and possess antioxidant activity, and therefore have a stabilizing effect on the safety of products under conditions of oxidative processes.

The method of obtaining hydrophobic flavonol and anthocyanin compounds from flavonoid-containing plant raw materials is carried out as follows.

Pomace of black currant berries, black chokeberry, red petals, onion husks are dried, crushed, extracted with a solution with a volume fraction of ethanol 96%, the pigment extract is separated by filtration and concentrated. The process of hydrolysis of glycosidic forms of natural flavonoids is carried out by adding concentrated orthophosphoric acid to the pigment extract in an amount of 4-6 wt. % of the dry matter content in the extract. Hydrolysis proceeds at a temperature of 70-80 ° C to a constant dry matter content in the extract. The precipitated flavonoid aglycones are then filtered off and dried.

The method for obtaining hydrophobic flavonol and anthocyanin compounds from flavonoid-containing plant materials is illustrated by the following examples.

Example 1 (prototype).

Homogenized natural anthocyanin-containing raw materials are treated with chilled or uncooled methanol or ethanol containing 1% hydrochloric acid. After settling and filtration, the anthocyanin extract is concentrated under vacuum at a temperature of 30-40 ° C, and then used to isolate and separate anthocyanins. Hydrolysis of anthocyanins is carried out in a 2N hydrochloric acid solution at a temperature of 100 ° C for 40 minutes or 6N hydrochloric acid at the same temperature for a shorter time.

Example 2.

Anthocyanin-containing raw materials (pomace of black currant or black chokeberry) are dried, crushed, extracted with a solution with a volume fraction of ethanol of 96%, the pigment extract is separated by filtration and concentrated.

The process of hydrolysis of glycosidic forms of natural flavonoids is carried out by adding concentrated orthophosphoric acid to the pigment extract in the amount of 4% of the dry matter content in the extract. Hydrolysis proceeds at a temperature of 70 ° C until a constant dry matter content of the extract.

The precipitated flavonoid aglycones are then filtered off and dried.

Example 3.

The petals of red flowers are dried, crushed, extracted with a solution with a volume fraction of ethanol of 96%, the pigment extract is separated by filtration and concentrated.

The process of hydrolysis of glycosidic forms of natural flavonoids is carried out by adding concentrated orthophosphoric acid to the pigment extract in an amount of 5% of the dry matter content in the extract. Hydrolysis proceeds at a temperature of 75 ° C until a constant dry matter content of the extract.

The precipitated flavonoid aglycones are then filtered off and dried.

Example 4.

The crushed dried flavonol-containing plant material (onion husks) is dried, crushed, extracted with a solution with a volume fraction of ethanol of 96%, the pigment extract is separated by filtration and concentrated. The process of hydrolysis of glycosidic forms of natural flavonoids is carried out by adding concentrated orthophosphoric acid to the pigment extract in an amount of 6% of the dry matter content in the extract. Hydrolysis proceeds at a temperature of 80 ° C to a constant dry matter content in the extract. The precipitated flavonoid aglycones are then filtered off and dried.

Obtained by the proposed method, hydrophobic flavonol and anthocyanin compounds were analyzed. Analysis data are offered in table. 1.

The implementation of the proposed method allows:

- to reduce the temperature of the hydrolysis process;

- to reduce the reaction time of hydrolysis;

- replace the toxic extractant methanol with ethanol approved for use in the food industry;

- to use hydrophobic flavonol and anthocyanin pigments for use in food, medical, perfumery and cosmetic industries.

Claims (1)

A method of obtaining hydrophobic flavonol and anthocyanin compounds from flavonoid-containing plant raw materials, including drying plant materials, grinding raw materials, extracting natural flavonoids with a solution with a volume fraction of ethanol 96%, separating the pigment extract and concentrating, characterized in that the process of hydrolysis of glycoside forms of natural flavonoids was carried out to the extract of concentrated orthophosphoric acid pigments at a temperature of 70-80 ° C, hydrolysis was carried out to a constant dry matter content in the extract, followed by filtration and drying of the precipitated flavonoid aglycones.