RU2385655C1 - Procedure for production of agar out of ahnfeltia - Google Patents

Abstract

FIELD: food industry.

SUBSTANCE: invention refers to food industry, particularly to production of agar. The procedure consists in steeping part of air-dry ahnfeltia in lime milk and in successive washing; while another part of raw material is crushed dry. Further, dry crushed and steeped not crushed raw material is mixed mainly at weight ratio 1:(4.0-4.5) and processed with steam at pressure not less, than 2 atm in a reactor. Produced condensate is poured out. Further, steamed raw material is threefold boiled at pressure not less, than 1 atm and agar is extracted in the same reactor. Produced fat is cleared off mechanical impurities, jellified, and cut into plates; the plates are washed, pressed, dried and crushed producing powdered agar.

EFFECT: developing efficient procedure of agar production.

2 cl

Description

The invention relates to the processing of algae to obtain gelling substances, in particular to the production of agar, and can be used in the food industry.

A known method of processing agar-containing algae [US Pat. RF №2103293, publ. 1998.01.27], which consists in grinding purified algae with simultaneous extraction of the dye, followed by separation of the resulting suspension into two fractions. In this case, the first fraction containing the dye solution is purified, concentrated, stabilized, and the second is subjected to extraction. The disadvantage of this method is the difficulty of separating the suspension into two fractions, as well as the low strength of the resulting agar due to extraction in a neutral medium.

A known method of processing red algae [US Pat. RF №2052962, publ. 1996.01.27], including washing algae, grinding and extracting a water-soluble pigment with water to obtain a dye supernatant that is clarified, concentrated and stabilized. The solid residue of the algae is treated with an alkali solution, the agar is extracted by extraction at a temperature of 80-90 ° C for 15-30 minutes, followed by cooling to jelly, dehydration and drying of the jelly and processing of the algae residue to obtain a feed additive. The disadvantage of this method is the use in the process of highly active alkalis (KOH, NaOH), which are environmentally unsafe.

The closest technical solution is a method for the production of agar from anfelia [US Pat. RF №2191523, publ. 2002.10.27], including the preparation of raw materials by soaking anfelia in water with the addition of milk of lime and washing, the subsequent extraction of agar in a battery of three autoclaves by seven-fold cooking according to the countercurrent principle with a pressure increase of 1.2 atm during the first and second cooking and 1 atm at each subsequent cooking, cleaning the resulting solution from mechanical particles by filtering and separating it, gelling the purified solution to jelly, washing, separating moisture, re-separation, followed by evaporation and drying the jelly to a powder state.

A disadvantage of the known technical solution is the insufficiently high quality of the resulting agar, which is due to the high pressure and, accordingly, the high cooking temperature, which leads to hydrolysis of the agar and, as a result, to obtain its low molecular weight fractions giving gels of reduced strength, as well as insufficiently high agar yield . In addition, the increased cooking temperature leads to an increase in the energy intensity of the process and a corresponding increase in the cost of the resulting agar, and high pressure in the reactor is associated with a complication of the equipment of the method.

The objective of the invention is to improve the quality of the resulting agar, increase its output, reduce costs, as well as simplify the hardware of the agar production method.

The problem is solved by a method of producing agar from anfelium, including soaking the raw materials in milk of lime, followed by washing, extracting the agar into the solution by repeated cooking of the prepared raw materials under pressure, subsequent purification of the resulting solution from mechanical impurities, its gelation to form a jelly, cutting the jelly into plates, washing, spinning and drying the obtained plates and obtaining agar powder, in which, unlike the known method, part of the raw material is subjected to dry crushing and mixing vayut the rest soaked in milk of lime uncrushed raw material mixture feed prior to cooking is treated with live steam in a reactor at a pressure of not less than 2 atm, emptied and the resulting condensate is recovered agar in the same reactor by triple cooking parboiled feedstock at a pressure of at least 1 atm.

The optimal loading of raw materials into the cooking reactor and the maximum percentage of agar yield is achieved with a mass ratio of dry crushed and soaked raw milk in lime milk, equal to 1: (4-4.5).

The method is as follows.

Part of the previously prepared raw materials, namely, washed in fresh water and dried (air-dry) anfelium, is soaked in milk of lime (1% solution of calcium oxide CaO) for at least 20 hours at a temperature of 18-20 ° C and a hydraulic module (ratio between the mass of anfelium and the mass of solution) 1: (10-12) with periodic stirring, which ensures its more complete release from mechanical and organic impurities, silt constituents and calcareous fouling. After soaking, the anfelia is washed in fresh water.

The other part of the previously prepared air-dry anfelium, without soaking, is crushed to the size of individual particles ≤5 mm. Crushing thalli of anfelia opens the access of the cooking solution to the internal tissues, as a result of which the extraction process is accelerated and the percentage of agar yield increases.

The anfelia prepared in two different ways (unfrozen and dry crushed soaked in lime milk) is mixed in the selected ratio, mainly at a mass ratio of dry crushed and soaked uncrushed anfelia 1: (4.0-4.5), loaded into an empty cooking reactor and processed direct steam followed by discharge of the condensate formed.

Steam is supplied to the reactor from below under pressure with a simultaneous discharge of air through the pressure relief valve at the upper point (cover) of the reactor until a steady stream of steam is obtained. The valve is closed and the raw materials are held at a constant vapor pressure of at least 2 atm for at least 1 hour at a temperature of 120-130 ° C. Then carry out pressure relief and drain condensate.

This technological operation of steaming promotes the release of agar from low molecular weight fractions, reduce its ash content and provides an increase in the quality of the target product (dry agar).

The ratio of crushed and crushed raw materials in the claimed interval allows to increase its bulk density and increase the load factor of the reactor at the stage of cooking.

Then carry out three times the extraction (carry out cooking in three stages). The first cooking is carried out with the addition of milk of lime with a CaO content of 1% at a water module of 1: 10-12, a temperature of 115-120 ° C and a pressure of at least 1 atm for 10-12 hours with periodic stirring with hot steam, which is fed through a bubbler tube. During the first cooking period, the agar is extracted mainly from uncrushed anfelia, which was previously soaked in a lime solution. The resulting broth, the concentration of agar in which is 0.5-1.0%, is drained.

The second cooking is carried out with the addition of a solution of milk of lime with a CaO content of 0.5% at a water module of 1: 8-10, a temperature of 115-120 ° C and a pressure of at least 1 atm for 10-12 hours with periodic stirring with hot steam. During the second cooking period, extraction is carried out simultaneously from two types of raw materials (crushed and soaked uncrushed). The resulting broth with an agar concentration of 0.5-1.0% is also drained.

The third cooking is carried out without the addition of milk of lime, with a water module of 1: 6-8, at a temperature of 115-120 ° C and a pressure of at least 1 atm for 10-12 hours. During the third cooking, extraction occurs predominantly from crushed raw materials, since by the beginning of it a small amount of agar remains in the previously soaked uncrushed anfelia. Navar with an agar concentration of 0.5-1.0% is drained.

After extraction, all obtained Navar are sent for purification from mechanical impurities by settling and separation and further technological processing: gelation, gel cutting into plates, followed by fresh water washing, dehydration, drying, grinding, which are carried out using one of the known methods.

As a result of triple (in comparison with the sevenfold used in the known method) cooking at each stage, a fat with a content of 0.5-1.0% agar is obtained, while the powder agar obtained from these fat meets the requirements of GOST 1628002001 and corresponds to the main parameters imported counterparts.

The algal residue after cooking can be used as an organic fertilizer.

Thus, the technical result of the proposed method is to increase its efficiency, because through the use of combined preparation of raw materials and a more complete loading of cooking equipment, it provides a higher coefficient of extraction of agar from anfelsia and a higher coefficient of utilization of equipment, as well as improving the quality of the obtained agar for account of the operation of preliminary steaming of raw materials. In addition, the proposed method is less energy intensive, simpler in hardware and allows to reduce the cost of agar obtained with its help.

An example of a specific implementation of the method.

I. Preparation of raw materials.

Raw materials are prepared in two ways:

1) 200 kg of pre-washed in fresh water and dried Anfelia tobuchinsky ((Ahnfeltia tobuchiensis) is soaked in 3 m ³ 0.5% milk of lime for 20 hours with periodic stirring, then washed in fresh water and loaded into a stainless steel reactor with a capacity 2.8 m ³ .

2) 50 kg of pre-washed in fresh water and dried anfelium are crushed on a KDU-2 crusher to a thalli size ≤ 5 mm and loaded into the same reactor.

II. Steaming raw materials.

The reactor is hermetically sealed with a lid, through the lower bubbler, sharp vapor is supplied to the reactor from below at a pressure of 4 atm with a simultaneous discharge of air through the pressure relief valve at the upper point (cover) of the reactor to obtain a stable steam jet. The valve is closed, the pressure in the reactor is raised to 2 atm and the feed is held at a constant vapor pressure of 2 atm for 1 hour at a temperature of 130 ° C. Then carry out pressure relief and drain condensate.

III. Extracting agar from Anfelia by cooking in three stages.

1st cooking. 2.5 m ^{3 of} milk of lime with a CaO concentration of 1% (hydraulic module 1:10) is poured into the same reactor, which has a false bottom made of stainless steel mesh for preliminary coarse filtration. Steam is supplied to the steam jacket at a pressure of 4 atm and heated until a steady stream of steam appears from the upper valve in the reactor cover. After that, the pressure relief valve is closed, the pressure in the reactor is raised to 1 atm and the raw materials are held for 12 hours with periodic mixing with hot steam, which is supplied through a bubbler. Then a sample of the solution is taken through a special valve at the bottom of the reactor. The sample is gelled for 20 minutes in cold water, if the strength of the obtained jelly reaches 200 g using a Valent device, the whole broth is poured onto a sump with preliminary filtration through a false bottom.

2nd cooking. In the same reactor, pour 2 m ^{3 of} milk of lime with a CaO concentration of 0.5% (hydraulic module 1: 8). Carry out cooking in the same way. After testing the agar for strength, the broth merges.

3rd cooking. 1.5 m ^{3 of} water is poured into the same reactor (hydraulic module 1: 6). Cooking is carried out similarly, the broth is drained.

IV. Getting dry agar.

The resulting Navar are subjected to sedimentation, filtration and separation. Then sent for further technological processing: gelation, cutting the gel into plates, washing, subsequent drying in a chamber shelf dryer and grinding the resulting agar plates.

Claims (2)

1. A method of producing agar from anfelia, including soaking the raw material in milk of lime, followed by washing, extracting the agar by repeated pressure cooking, subsequent purification of the resulting solution from mechanical impurities, gelling it to form jelly, cutting the jelly into plates, washing, spinning and drying the obtained plates and obtaining powder agar, characterized in that part of the raw material is subjected to crushing in dry form and mixed with the rest of the raw materials soaked in lime milk, mixed cheese e before cooking is treated with live steam in a reactor at a pressure of not less than 2 atm, emptied and the resulting condensate is recovered agar in the same reactor by triple cooking parboiled feedstock at a pressure of at least 1 atm. 2. The method according to claim 1, characterized in that the dry crushed and soaked in lime milk uncrushed raw materials are mixed in a mass ratio of 1: (4.0-4.5).