RU2033056C1 - Fruit pectin production method - Google Patents

Abstract

FIELD: food industry. SUBSTANCE: method involves pomace washing with addition of some acidified mineral acid. The rate of supplementation is such that pH of the solution for washing apple pomace is 2.5-3.0 and that for citrus pomace 2.5-3.5. EFFECT: higher product quality.

Description

 The invention relates to a technology for producing food gelling agents and can be used for the production of pectin from plant materials.

 Before extraction of pectin from plant materials, it is leached by washing with water. The purpose of the removal of substances soluble in water from the extracted material, including sugars, organic acids, mineral salts, etc. which complicate the processing of pectin extract, the extraction of pectin and, in addition, in the case of transition to pectin preparations reduce their purity and thereby technical value. The leaching technology involves the addition of water at a certain temperature and in a certain ratio, and according to some authors, the water should be hard to avoid hydratopectin losses (Henglein F.A. Biochemical methods of plant analysis. M. Foreign literature, 1960, p. 280).

 Other researchers came to the conclusion that it is more expedient to use distilled water for leaching, which, in comparison with using hard water, allows subsequent extraction of pectin to increase its yield from raw materials.

 However, the quality of the extracted pectin decreases somewhat (B. Sewer-Zewandowska. Badania metod lugowania wytlokow jablkowych i ekstrakcji zwiatkow pektynowych. Proceedings of the Institute of Fermentation Industry. Warsaw).

 According to the technology for the production of pectin from apple and citrus squeezes adopted at domestic pectin enterprises, the raw materials for the production of pectin are washed with water, using ordinary tap water for this purpose.

 Studies of the pectin extract obtained after acid hydrolysis of raw materials showed that it is characterized by a variable amount of hardness cations, the source of which is the salts contained in both the feedstock and the process water used for washing and hydrolysis. Evaporation of pectin extract in vacuum evaporation plants is accompanied by a multiple increase in the concentration of hardness salts, which leads to their deposition on heat-exchange surfaces.

 As a result, the evaporation mode worsens, thermal destruction of pectin increases, its gel-forming ability decreases, which often leads to defective products.

 Reducing the solubility of hardness salts when treating pectin concentrate with alcohol to precipitate pectin also contributes to the formation of deposits on the rotor of the centrifuge, in the pipelines of the centrate, in the distillation apparatus used for the recovery of ethanol. Part of the sediment contaminates pectin, reducing quality.

The prototype is the technology adopted at existing pectin enterprises, in accordance with which apple squeezes are subjected to double washing. The first washing is combined with loading them into the extractors in the form of an aqueous suspension of hydraulic feed: 600-700 kg of squeezed mixture are mixed with 5-6 m ^{3 of} water, stirred for 20 minutes and pumped to the extractors equipped with drainage, while draining the washing water. Then a second washing is performed: the extracts in the extractor are poured with warm water to a volume of 10 m ³ , stirred for 15 minutes, the mixture is defended for 20 minutes and the washing water is filtered.

The content of pectin in citrus squeezes is higher than in apple ones, and there are less soluble ballast substances in them. Therefore, the permissible content of ballast substances is usually achieved as a result of a single washing in the process of hydrofeed: 250-300 kg of pomace are mixed with 5-6 m ^{3 of} water and the process is conducted, as for apple pomace.

 The concentration of hardness cations in apple squeezes is 100-150 mEq / kg, in citrus pomace 400-500 mEq / kg.

When washing with distilled water, carried out in accordance with the prototype, about 20% of the initial content of hardness cations is removed from apple squeezes, and only about 5% from citrus fruits. to adverse events, as indicated above. Use for flushing tap (hard) water exacerbates these phenomena [1]
The purpose of the invention is to reduce the concentration of hardness cations in the pectin extract, increase the gel-forming ability of dry pectin, increase the yield of pectin and save acid.

 This goal is achieved in that the squeeze washing is carried out with distilled water, acidified with mineral acid in an amount that provides a suspension pH of 2.5-3.0 when washing apple squeezes and 2.5-3.5 for citrus squeezes.

Studies on washing dried apple and citrus squeezes showed that the concentration of hardness cations in the washing water increases if water with acid (nitric, phosphoric) is added for washing. Washed at ambient temperature ≈25 ^{° C} to reduce the loss of pectin.

 When washing apple squeezes (GM 1:15), the number of hardness cations removed with washing water when washing pH is lowered from 4 to 1.8 increases by about 2 times, and when washing citrus squeezes (GM 1:20) 5-6 times .

 The concentration of hardness cations in the pectin extracts obtained from the extracts so washed is also reduced. Moreover, in extracts from both apple and citrus squeezes with the same alcohol-precipitated pectin content of 0.5%, the same concentration of hardness cations ≈6 mEq / l is achieved.

 As the pH decreases, the total consumption of nitric acid for washing and hydrolysis of the raw material (upon receipt of 1 ton of pectin) is initial when washing in the pH range 3.0-3.5, in the case of citrus squeezes 2.5-3.5.

 For both types of raw materials, the acid consumption increases sharply when washing in a pH zone below 2.5 in comparison with its consumption when washing the marc with water without acidification. The concentration of hardness cations in the pectin extract from pomace washed at a pH of less than 2.5 decreases insignificantly.

 Thus, in order to reduce the concentration of hardness cations in the pectin extract and save acid, it is advisable to wash the apple and citrus squeezes with acidified distilled water.

Example 1. 60 g of dried pomace of grapefruit was washed with a weak solution of nitric acid at a concentration of 0.0125 g-equiv / dm ³ (pH 2.6; water module 1:20) with periodic stirring for 30 minutes. The washing water was filtered off, the washed pomace was poured with hot distilled water to a volume of 1 dm ³ and the flask containing the contents was placed in a temperature-controlled water bath. After reaching the temperature of the mixture in the flask was 85 ^{° C} set pH 1.30 by adding 20 cm ³ of 20% nitric acid solution. From this moment, the hydrolysis time began, the duration of which is 150 minutes.

After its expiration, the hydrolysis was stopped by adding cold distilled water to a volume of 2 dm ³ , stirred and left for 2 hours. The pectin extract was separated and then filtered through filter board with the addition of kieselguhr.

 Pectin was precipitated by mixing the purified extract with ethyl alcohol in a ratio of 1: 1.

Coagulated pectin was separated from the alcohol liquid and washed with 1 dm ^{3 of} alcohol, which was divided into three portions. The washed pectin was dried at a temperature of 65 ^about C for 3 hours

Received 9.7 g of pectin, which corresponds to the calculated (calculation according to TU 10.963.27-91 "Squeezed dried apple") its content in raw materials 24% with the following indicators: Degree of esterification, 62
Student-forming ability, ^o T-B 270
The content of hardness cations, mEq / kg 200
The indicators of pectin isolated in a similar way, after washing with water without acidification, are as follows: The degree of esterification, 63
Student-forming ability, ^about TB 255
The content of hardness cations, mEq / kg 290
PRI me R 2. 120 g of dried apple pomace was washed with 1 dm3 of distilled water (GM 1: 8.3) with periodic stirring for 20 minutes The wash water was drained, and the washed squeeze was subjected to a second wash with water with the addition of 4 cm ^{3 of a} 20% nitric acid solution, the pH of the wash suspension was 2.6, the water module was 1:15, the washing time with periodic stirring was 30 minutes. The washing water was filtered off, the washed pomace was poured with hot distilled water to a volume of 1 dm ³ and the flask was placed in a temperature-controlled water bath.

After reaching the temperature of the mixture in a flask of 85 ^about With set the pH to 1.8, adding 3.8 cm ^{3 of a} 20% solution of nitric acid. The duration of hydrolysis is 60 minutes After its expiration, hydrolysis was stopped by adding cold distilled water to a volume of 2 dm ³ , stirred and left for 2 hours. The extract was separated, pectin was isolated and treated as described in Example 1.

Received 5 g of pectin, which corresponds to the calculated content of 6.2% in raw materials with the following indicators: The degree of esterification, 76
Student-forming ability, ^about TB 320
The content of hardness cations, mEq / kg 150
The indicators of pectin isolated in a similar way, after washing with water without acidification, are as follows: The degree of esterification, 76
Student-forming ability, ^about TB 300
The content of hardness cations, mEq / kg 205.

Claims (1)

 METHOD FOR PRODUCING PECTINE FRUIT Squeezes, including washing the raw material with water, acid hydrolysis in hot water, separating the pectin extract, purifying it, concentrating it, treating the pectin extract with alcohol, separating the solid phase, washing it with alcohol, drying, characterized in that, in order to reduce the concentration of hardness cations in the pectin extract, increase the gel-forming ability of dry pectin, increase the yield of pectin and save acid, washing the pomace is carried out with distilled water, acidified with eralnoy acid in an amount as to obtain a solution pH 2.5 3.0, for washing and apple pomace 2.5 3.5 citrus pomace.