IL94803A

IL94803A - Purification of extracted date juices without use of additives

Info

Publication number: IL94803A
Application number: IL9480390A
Authority: IL
Original assignee: Tatabanyi Banyak Vallalat; Zoldsegtermesztesi Kutato Inte
Priority date: 1989-07-19
Filing date: 1990-06-20
Publication date: 1994-06-24
Also published as: HUT54477A; CZ284603B6; DE4022867A1; CZ357290A3; IT9067492A1; DD296704A5; HU206819B; IT1240967B; BG50822A3; IL94803A0; PL286111A1; IT9067492A0; CH680764A5

Description

94803/2 ο>οο·>ια vno>¾> t > nsuon o>non a -po> t Purification of extracted date juice without use of additives ) Tatabanyai Banyak Vallalat ) Zoldsegtermesztesi Kutato Intezet Fejleszto Vallalat : 80946/7 The invention relates to a purification process of date juice without additives.

The most critical steps of the production of date sugar are the removal of pectin from the crushed, extracted and rather contaminated sugar solution of high pectin content and the clear-filtration of said solution.

According to known methods the sugar solution of a high pectin content is decomposed in the presence of pectin de composing enzymes (e.g. products of Rohm, Grinstedt) in a reactor suitable for this purpose and thereafter the solution thus obtained is clear-filtered - after an appropriate time period - in the presence of filtration additives (e.g. bentonite or perlite) by the use of frame filter press equipments .

For this enzymatic decomposition process a large amount of pectin decomposing enzyme is needed, it may amount to 0.1-0.3% calculated for the amount of the sugar solution to be treated.

To ensure the working of the enzymes a temperature ranging from 40 to 50°D and a very exact optimal enzyme concentration are required in lack of these circumstances the decomposition is incomplete, the solution remains contaminated with pectin or the decomposing enzymes lose their activity. - - ± η the basis of the aforementioned it is obvious that the decomposition of the pectin is the most critical and most expensive step of the date sugar production , the performance of which inf luences the quality of the end product , i . e . the date sugar .

In the USP 4, 322, 448 a process is disclosed relating to the concentration of natural fruit juices using reverse osmosis.

In the JP No. 60226503 a process for concentrating pectine extract is described, wherein the hot extract is contacted with a polymer membrane which is vapor permeable but water- impermeable. From the extract vapor is generated and allowed to penetrate to the other side of the membrane, where it is condensated .

In the DE 3517886 the purification and processing of liquids obtained from different agricultural products are described wherein the purification may be carried out with the known ultrafiltration. According to the disclosed method the purification is carried out after the recovery of the aroma materials and removal of pectine contained in the raw fruit and vegetable juice and the essence of this invention is the processing of the concentrate obtained by the utrafiltration.

According to these methods, however, the aim is the concentration of the juice and the pectin respectively or the processing of the concentrate but not the removal of the pectin. - 2a - 94803/1 According to the process described in HU PS No.. 165,076 the decomposition of pectin is carried out by the use of lime. In this process the pectine is precipitated in form of calcium pectate, thereafter the excess lime is neutralized with carbonic acid and the required pH value is adjusted.

The drawback of this method is the high cation and anion content formed in the sugar solution due to the lime treatment, due to which the loading of the ion exchange columns used in course of the date sugar ■ production considerably increases and so the waste of the ion exchange resin also increases which results in rather high production costs.

After this decomposition process the frame filtration or vacuum drum filtration carried out in the presence of the previously mentioned additives is also required.

- - We have recognized that the removal of pectin and the clear-filtration can be carried out in one step without any additives by the use of ultrafiltration units equipped with capillary or- dimensioned tube membranes.

In the process according to the invention the date sugar solution obtained from the extraction is first introduced in a common storage tank, thereafter by the aid of a pump it is forwarded to the tanks of the individual units. These ultrafiltration units work at a temperature of 30-70°C and at a pressure of 0.1-1.0 MPa in batch or continuous mode, i.e. in a one-step or cascade system. The cut off value of the synthetic capillary or dimensioned tube membranes can be chosen - depending on the pretreatment of the date - between 5000 and 50000 Dalton.

The obtained date sugar filtrate (permeate) is free of pecti n and is clear, the residual concentrate contains 3-5% of pectin and may be recycled or utilized for any other purpose.

The advantages of the process according to the invention are as follows: the use of pectin decomposing enzymes and other filtration additives can be eliminated and so no apparatus, required for the conventional operations, e.g. frame or vacuum drum filters, is needed; instead of the usual two- or more operations (pectin decomposing reactor and several filters) the depectinization is carried out in a single step; - the sugar waste, which may amount to 20-30% when using the known lime depectinization method, can be entirely eliminated as the membrane filtration does not influence' the pH value; - the ion exchange columns are not overloaded as the solutions to be treated do not contain foreign ions; - the obtained membrane filtrates are colloidal and the colouring agent content thereof is more favourable as that of the filtrate obtained by a traditional method .

The scheme of the multi-stage ultrafiltration apparatus and the flow diagram of the process according to the invention is shown in Figure 1.

The extracted date juice is introduced into a common storage tank (T) from which it is forwarded by the aid of a pump into the storage tank of each unit (1 to n). Thereafter the solution to be treated is introduced - through a pressure intensifier and a circulating pump - into the ultrafiltration units (1 to N) wherein the removal of the ' .... pectin and the clear-filtration under the above mentioned conditions are carried out.

The clear date sugar solution free of pectin there¬ after is forwarded - after an appropriate control (A) - to the ion exchange system.

In Figure 2 the place of the ultrafiltration unit in the whole sugar procedure can be seen.

Example Extracted date juice was treated in a "batch-mode" operating apparatus containing ultrafiltration membranes, for 6 hours at a temperature of 55°C and at a pressure of 0.25 MPa. In the ultrafiltration apparatus units of type POROFILT UFTA-PSF- 10-1.2 were used and the cut off value of the membranes was 10000 Dalton.

The obtained filtrate was clear and free of pectin, which was checked by enzyme assay and nephelometry .

Claims

-5- What we claim is:

1. Process for removal of pectine from extracted date juice and clear-filtration thereof without any additives c h a r a c t e r i z e d by ultrafiltration in one step of the extracted date juice in an ultrafiltration apparatus equipped with membranes having a cut-off value of 5000--50000 Dalton at a temperature of 30-70°C and at a pressure of 0.1-1.0 MPa.

2. Process according to Claim 1 ch a r a c t e r i z e d by using capillary or dimensioned tube membrane in the ultrafiltration apparatus.

3. Process according to Claim 1 c h a r a c t e r i z e d by carrying out the ultrafiltration - following the requirement of the whole sugar production system - in batch and/or continuous mode, i.e. in one-step or cascade system. or fhe Applicants