RU2248993C2 - Method of preparing pectin extract from citrus cakes - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention provides a method of isolating pectin preparation from citrus cakes, which method comprises hydrolysis-extraction of cakes and separation of liquid phase, hydrolysis-extraction operation, according to invention, being preceded by consecutive extraction first with dimethylformamide and then with liquid carbon dioxide at superatmospheric pressure, which is reduced to atmospheric value after separation of the second extract. Hydrolysis-extraction operation is accomplished by consecutively conducting the process in concurrent and countercurrent modes introducing intermediate pressing and using water as countercurrent extractant and extract separated after countercurrent stage as concurrent extractant.

EFFECT: reduced loss of pectin without worsening its organoleptic properties.

Description

The invention relates to a technology for the isolation of pectin from plant materials.

A known method of producing pectin from citrus squeezes, providing for their extraction with water, hydrolysis-extraction of the solid phase, separation of the liquid phase and its concentration or drying (Donchenko L.V., Technology of pectin and pectin products - M .: DeLi, 2000, p. 96- 105).

The disadvantage of this method is the high loss of pectin with an aqueous extract.

The technical result of the invention is to reduce the loss of pectin without compromising its organoleptic properties,

This result is achieved by the fact that in the method of producing pectin from citrus extracts, which provides for their hydrolysis-extraction and separation of the liquid phase, according to the invention, before hydrolysis-extraction they are sequentially extracted with dimethylformamide and liquid carbon dioxide at a pressure above atmospheric, and after the second extract is separated, the pressure is released to atmospheric, while hydrolysis-extraction is carried out by sequentially carrying out the process in a direct flow and countercurrent with an intermediate pressing and using water as an extractant at the stage of countercurrent extraction, and at the stage of direct-flow extraction of the extract separated after countercurrent extraction.

The method is implemented as follows.

Citrus squeezes are crushed if necessary (L. Donchenko, Technology of pectin and pectin products. A textbook for university students. - M .: DeLi, 2000, p.96-106), and then extracted with dimethylformamide and the extract is separated by known methods (Bykova S.F., Theoretical and experimental foundations for creating a fundamentally new resource-saving technology for the production of vegetable oils.Abstract of dissertation, Doctor of Technical Sciences - St. Petersburg: VNIIZh, pp.21-26; Demchenko PP Improving the technology of extraction of oil from seeds Sunflower. Abstract of a dissertation of a candidate of technical sciences - .: ARSRIF 1982, s.6-14) containing essential oils and glycosides, which have a bitter taste. Next, the solid phase is extracted with liquid carbon dioxide at a pressure above atmospheric pressure corresponding to the saturated vapor pressure of the extractant at the extraction temperature, and the extract is separated without changing the pressure (Kasyanov G.I. et al. Processing of plant materials with liquefied and compressed gases - M .: AgroNIITEIPP, 1993, 40 p.). Residues of dimethylformamide pass into the extract, which excludes the further transition of dimethylformamide according to the stages of the process and its entry into the target product. The pressure over the solid phase is sharply dumped to atmospheric. This leads to a sharp boiling of liquefied gas and explosive grinding of plant materials, accompanied by the destruction of cell membranes. Next, the solid phase is directed to hydrolysis-extraction.

It should be noted that pectin substances are not soluble in either dimethylformamide or carbon dioxide, which eliminates their loss with separated extracts and, accordingly, increases the yield of pectin substances in comparison with the closest analogue. While the initial content of pectin in citrus squeezes is from 8.9 to 14.9% by dry matter, and the content of the water-soluble fraction in it is about 33% (Donchenko L.V., Technology of pectin and pectin products. - M .: DeLi, 2000, p. 53, 97), the loss of pectin as a result of its deep hydrolysis can be estimated for the proposed method and the closest analogue according to the known dependences (Altunyan MK, Kinetics of the destruction of the polysaccharide in the process of producing pectin. Abstract of dissertation .n. - Krasnodar: KPI, 1988).

Hydrolysis-extraction is carried out in a direct flow and counterflow, on any sequentially installed direct-flow and counter-current extractors or on a sectional extractor of a special design (O. Kvasenkov, Improving the technology for obtaining and using plant extracts in the food industry. Thesis. - M.: VNIIKOP - RosZITLP, 1996, p. 28) with process parameters determined by known methods (I. Ilyina, Scientific basis of the technology of modified pectins. - Krasnodar: SKZNIISiV, 2001, p. 88-156). To reach the steady state, the entire extraction system is filled with one of the phases: liquid, that is, water, or solid, that is, squeezed, according to a subjective choice. After this, the supply of the second phase begins and, as soon as it reaches the exit, they start feeding and moving the first phase, and the process enters into a steady state. In the steady state, at the countercurrent extraction stage, water is used as the extractant. Water does not have a hydrolyzing ability with respect to pectin substances and extracts from the raw material only those substances that are in it in advance in a water-soluble form. In addition to pectin, at the countercurrent extraction stage, mono- and oligosaccharides and organic acids pass into the extract. The separated extract is fed to a straight-through extraction step. The solid phase at the outlet practically does not contain soluble substances, which allows us to conclude that the loss of pectin is reduced in comparison with the closest analogue, in which hydrolysis-extraction by insisting in the solid phase after extraction always contains extract residues and loss of pectin is inevitable.

At the stage of direct-flow management of the hydrolysis-extraction process, intensive hydrolysis of protopectin occurs due to the development of the contact surface of the phases, the destruction of cell membranes and the presence of both native citrus extract acids and acids introduced in the extract. Since the content of acids in citrus fruits and squeezes, respectively, varies depending on the type, variety and growing conditions, the required acid concentration is achieved at the stage of direct-flow hydrolysis-extraction process by known methods: by adjusting the ratio of phase flow rates and / or introducing into the extract separated after countercurrent extraction, an additional amount of acids according to the results of measuring the pH of the reaction mixture at the input of the solid phase, which ensures optimal flax hydrolysis conditions. The development of the phase contact surface and the destruction of the cell membranes of raw materials increase the availability of protopectin, which reduces the time of its hydrolysis and reduces the possibility of deep hydrolysis of soluble pectin substances and, accordingly, reduces their loss. After completion of the direct-flow stage of the process, the liquid phase is separated by gravity and the extraction of the solid phase. The concentration of pectin in the liquid phase is higher than in the closest analogue, which in some cases eliminates the need for its concentration, for example, when using the target product in the food industry in the beverage industry. The solid phase, containing the remains of extractive substances, enters the countercurrent stage of the process. At this stage, pectin substances that are converted to a soluble state are exposed to acids, the concentration of which decreases during the process, which reduces the possibility of deep hydrolysis of pectin and, accordingly, reduces its loss compared to the closest analogue according to experimental data, from an average of 33 to 8% of initial content and coincides with the analytical calculation according to the above methodology.

Thus, the proposed method can reduce the loss of pectin without compromising its organoleptic properties.

Claims (1)

A method of producing pectin from citrus squeezes, providing for their hydrolysis-extraction and separation of the liquid phase, characterized in that before hydrolysis-extraction they are sequentially extracted with dimethylformamide and liquid carbon dioxide, at a pressure above atmospheric, and after separation of the second extract, the pressure is released to atmospheric, this hydrolysis-extraction is carried out by sequentially carrying out the process in a direct flow and in countercurrent flow with an intermediate extraction and using as Krastenta at the stage of countercurrent extraction of water, and at the stage of direct-flow extraction of the extract separated after countercurrent extraction.