RU2490867C1 - Method of determining volume of fraction of volatile compounds in ethereal oil of mint leaves - Google Patents

Abstract

FIELD: agriculture.

SUBSTANCE: invention relates to the field of agriculture and food industry, as well as aromatherapy. In the method the volume of fraction of volatile compounds of ethereal oil of mint leaves is determined in a period of technical ripeness. The volume of fraction is calculated from the difference between the amount of ethereal oil of secretory glands, obtained based on the number and size of the glands per unit of area of mint plant leaves using light microscope with a video system Lumenera Infinity 2 followed by data processing using the program Infinity camera V:5.02, and the volume of ethereal oil obtained by the method of hydrodistillation.

EFFECT: method enables to determine quickly the content of fraction of volatile compounds in the ethereal oil and carry out the selection of breeding material.

3 cl, 2 tbl, 2 ex

Description

The invention relates to the food industry, aromatherapy and the production of pharmacy leaf, and for the evaluation of hybrids and varieties of mint by the number of volatile compounds in essential oil of mint. Spicy aromatic properties of peppermint essential oil have been known for a long time. The main purpose of peppermint is to obtain essential oil for extracting menthol from it for the pharmaceutical industry, the second, no less important, direction of using peppermint plants is the food industry, the production of pharmacy leaves and aromatherapy, where its aroma is important, i.e. the presence of volatile compounds. Mint leaves are used as an integral part as an aromatic additive in various drinks, including teas, and for preparing collections of medicinal plants, as native peppermint essential oil contains a fraction of volatile compounds that quickly evaporate when heated and create a unique aroma. Moreover, the oil of each of the numerous interspecific hybrids, intraspecific clones and varieties has a unique aroma, determined by the composition and percentage of volatile compounds.

Essential oil accumulates in the spherical outgrowths of the epidermis of the leaves of mint plants, called secretory glands. They are a spherical tank, consisting of a cavity filled with oil, with a thin outer shell, and legs, with which a piece of iron is attached to the surface of the sheet.

There has long been a known method of extracting the essential oils "enflerage", the principle of which is that the oil that evaporates from the flowers is absorbed by sorbents (solid fats, activated carbon). From the aromatic mass, the essential oil is extracted with a solvent.

The closest in technical essence to the claimed method is a method of extraction of raw materials with solvents in column apparatus, obtaining essential oil with subsequent determination of its component composition by a combination of gas chromatography and mass spectrometry methods (Kheifits L.A., Dashunin V.M., 1994). The method allows to determine the composition of the components of the essential oil and, in particular, volatile compounds. The disadvantages of this method are the duration of the analysis and the need for high-precision and expensive equipment.

The problem solved by the invention is the creation of a simpler method for determining the volume fraction of volatile compounds of essential oil of interspecific hybrids, intraspecific clones and mint varieties. The problem is solved by taking into account the number and morphological parameters of the secretory glands on mint leaves, selected in the phase of technical ripeness, calculating the volume of essential oil of the glands per unit area of leaves (1000 cm ² ). At the same time, the content of essential oil in the leaves of mint is determined by hydrodistillation (the Clevenger method modified by Loshkarev (GOST 24027.2-80)). The resulting difference in the content of essential oil between the two methods is a fraction of volatile compounds. A light microscope with a Lumenera Infinity 2 video system or digital camera, a ruler for capturing the scale when photographing, or a binocular with an ocular micrometer are required; instrument for determining the essential oil.

Working process

10-30 leaves of 5-7 pairs of 2-3 tiers of the main flower-bearing shoot in the phase of technical ripeness are selected from the mint plants being analyzed. in this phase, the formation of essential oil glands ends and the highest oil content is observed in them.

Using a video system or digital camera attached to a light microscope, 10 sections of each sheet are photographed at a magnification of × 500 on the top and bottom sides, since the glands are often located on both sides of the sheet. The number of pieces of iron in the frame is calculated on the obtained images using the Infinity camera V: 5.02 program, the surface area of the sheet in the frame in cm is determined, the number of pieces of iron per 1 cm ^{2 of the} upper and lower sides of the sheet. Their diameter is also measured and the average value of the diameter of the glands is calculated.

It is possible to carry out these calculations using a scale ruler, for which it is photographed and taken into account that 1mm = 1000mkm.

In the absence of a light microscope, similar measurements can be carried out using a binocular. Accounting for the number of glands in the field of view, their diameter and the area of the field of view is carried out using an ocular micrometer.

Using the data obtained, calculate the volume of essential oil of iron per 1000 cm ² leaf area according to the formulas:

V ₁₀₀₀ = V _top + V _bottom ;

V _{top or bottom} = 4 / 3πR ³ × n × 1000,

where V ₁₀₀₀ - the volume of essential oil of iron per 1000 cm ² leaf area, cm ³ ;

V _top - the volume of essential oil of the glands on the upper side, cm ³ ;

V _bottom - the volume of the essential oil of the glands on the lower side, cm ³ ;

π = 3.14;

R is the radius of the glands, cm;

n is the number of glands per 1 cm ^{2 the} surface of the sheet, pcs.

At the same time, in the leaves of the analyzed mint plants, the content of essential oil is determined by hydrodistillation. To do this, 200-300 g of fresh leaves are placed in a device for distillation of essential oil and according to GOST 24027.2-80, essential oil is obtained and its volume is measured. The mass of 50 mint leaves is fixed, their area is determined using a planimeter, and the mass of 1000 cm ^{2 of} the surface area of the leaves is calculated by the formula:

$$M_{1000}=\frac{m_{\mathrm{fifty}}\times 1000}{s_{\mathrm{fifty}}},$$

where M ₁₀₀₀ - weight 1000 cm ^{2 the} surface of the leaves, g;

m ₅₀ - mass of 50 leaves, g;

s ₅₀ - surface area of 50 leaves, cm ² .

Recalculation of the amount of essential oil obtained by hydrodistillation per 1000 cm ² the surface area of the leaves is carried out according to the formula:

$$V{*}_{1000}=\frac{M_{1000}\times V^{*}}{n\mathrm{but}\mathrm{at}e\mathrm{from}\mathrm{to}\mathrm{but}},$$

where v *₁₀₀₀ - the volume of essential oil obtained by hydrodistillation per 1000 cm² leaf surface area, cm³;

V * is the volume of the essential oil obtained by hydrodistillation, cm ³ ;

M ₁₀₀₀ - weight 1000 cm ² of leaf surface, g.

A hinge is a sample of fresh leaves taken for hydrodistillation. The determination of the volume of the fraction of volatile compounds in mint leaves is calculated by the formula:

V _lf = V ₁₀₀₀ -V * ₁₀₀₀ ,

where V _lf - volume fraction of volatile compounds in essential oil of mint leaves, cm ³ ;

V ₁₀₀₀ - the volume of essential oil (total volume of glands) per 1000 cm ² leaf area, cm ³ ;

V * ₁₀₀₀ - the volume of essential oil obtained by hydrodistillation per 1000 cm ² the surface area of the leaves, cm ³ .

The content of the fraction of volatile compounds in percent in the essential oil of mint leaves is determined by the formula:

$$\frac{V_{l.f}\times \mathrm{one\; hundred}}{V_{1000}},$$

where V _lf - volume fraction of volatile compounds in essential oil

mint leaves, cm ³ ;

V ₁₀₀₀ - the volume of essential oil (total volume of glands) per 1000 cm ²

leaf area, cm ³ .

Example 1. Calculation of V _lf for mint varieties of old selection, zoned for Ukraine and southern regions of Russia, grown on the experimental section of the laboratory in the Main Botanical Garden of the Russian Academy of Sciences. 30 leaves of 5-7 pairs of 2-3 tiers of the main flower-bearing shoot were taken from the analyzed plants in the phase of technical ripeness of each variety, the number of secretory glands, their diameter and V _{1000 were} calculated. At the same time, samples of fresh leaves of each cultivar were taken and the content of essential oil of hydrodistillation methods was determined. The volume fraction of volatile compounds was determined and their content of essential oil of mint varieties of old selection was calculated (Table 1).

Table 1. Determination of the volume of the fraction of volatile compounds in peppermint essential oil. grade volume of essential oil, cm ³ The content of the fraction of volatile compounds in essential oil of mint,% total volume of glands
V ₁₀₀₀ oil volume after hydrodistillation, V * ₁₀₀₀ volume of volatile compounds, V _lf 1. Krasnodar 2 0.509 0.133 0.376 73.9 2. Kuban 6 0.646 0.212 0.434 67.2 3. Simferopol 200 0.664 0.180 0.484 72.9 4. Muscovite 0.605 0.224 0.381 63.0 5. Udaychanka 0.766 0.337 0.429 56.1 6. Mitcham 0,500 0.166 0.334 66.8 7. Medicinal 4 0.583 0.280 0,303 52.0

As can be seen from the table, in the composition of the essential oil of mint varieties of old selection, obtained on the basis of M.piperita, the content of the fraction of volatile compounds exceeds 50%, and in varieties Krasnodar 2 and Simferopol 200 exceeds 70%. These varieties are more effective to use fresh - in the food industry or aromatherapy, and for a pharmacy leaf. When using them to obtain the essential oil, maceration methods should be used, since when using the hydrodistillation method, the fraction of volatile compounds is lost, which leads to a loss in the yield of the essential oil and its quality deterioration.

Example 2. Calculation of V _lf for interspecific hybrids, intraspecific mint clones grown in the experimental section of the laboratory in the Main Botanical Garden of the Russian Academy of Sciences.

30 leaves of 5-7 pairs of 2-3 tiers of the main flower-bearing shoot were taken from the analyzed plants during the technical ripeness phase of each variety, the number of secretory glands, their diameter and V ₁₀₀₀ were calculated. Simultaneously, fresh leaves of each variety were taken and the content of essential oil of hydrodistillation methods was determined. The volume fraction of volatile compounds was determined and their content of essential oil of mint varieties of old selection was calculated (Table 2).

Table 2. Determination of the volume of the fraction of volatile compounds in peppermint essential oil. grade volume of essential oil, cm ³ The content of the fraction of volatile compounds in essential oil of mint,% total volume of pieces of iron, V ₁₀₀₀ oil volume after hydrodistillation, V * ₁₀₀₀ the volume of volatile compounds, V _L.F Intraspecific tetraploid clone of M. arvensis, 0.573 0.313 0.260 45.4 Intraspecific clone of M. arvensis (NV-74) 0.670 0.151 0.519 77.5 Intraspecific clone M. arvensis (17-Taiwan) 0.502 0.170 0.332 66,2 Intraspecific clone M. arvensis (18-Japan) 0.541 0.191 0.350 64.7 Intraspecific clone M. arvensis (24-Syktyvkar) 0,094 0,025 0,069 73.5 Intraspecific clone of M. arvensis (19-Crimea) 0.460 0,072 0.388 84,4 Interspecific hybrid of M. piperita and M. crispa
Intraspecific clone of M. crispa (Crimea) 0.611 0.165 0.446 73.0 0.745 0,100 0.645 86.6

As can be seen from the table, in the composition of the essential oil in most intraspecific clones of mint M arvensis, the content of the fraction of volatile compounds is from 65 to 85% - these samples can be used fresh in the food industry, on the pharmacy sheet and in aromatherapy. Only in the tetraploid clone M. arvensis the content of the fraction of volatile compounds was less than 50%, therefore, it can be recommended for the production of essential oils by hydrodistillation.

Thus, our proposed method for determining the volume of the fraction of volatile compounds in essential oil of a mint leaf allows you to quickly evaluate the content of the fraction of volatile compounds in essential oil and to select material for the food industry, production of a pharmaceutical sheet and aromatherapy.

Information sources

1. Kheifits L.A., Dashunin V.M. Perfumes and other perfumery products. - M .: Chemistry, 1994. - P.185.

2. GOST 24027.2-80. Herbal raw materials. Methods for determining humidity, ash content, extractive and tannins, essential oils.

Claims (3)

1. The method of determining the volume fraction of volatile compounds of essential oil of mint leaf during the period of technical ripeness, characterized in that it is calculated by the difference between the volume of essential oil of secretory glands obtained on the basis of the number and size of glands per unit area of leaves of mint plants using a light microscope with a video system Lumenera Infinity 2, followed by data processing using the Infinity camera V: 5.02 program, and the volume of essential oil obtained by hydrodistillation. 2. The method according to claim 1, characterized in that the volume of essential oil of the secretory glands is obtained using a light microscope with a digital camera and a scale ruler. 3. The method according to claim 1, characterized in that the volume of essential oil of the secretory glands is obtained using a binocular with an ocular micrometer.