Editor: Rud Frik Madsen,
Message from the President
Now that the Proceedings have been published and the management of ICUMSA publications has been restructured, the activity of our Commission centres on the work of the Referees and Associate Referees, who must now consider and comment on the Recommendations adopted in Berlin.
Among the latest innovations is the new format of our website which can now be easily accessed thanks to work carried out by the webmaster of the University of Ferrara and I would like to express my sincere thanks for this assistance. Following a suggestion from Dr. Schäffler, we are trying to register our site on the internet, so that everybody who uses Webferret can find the ICUMSA website without knowing the exact address of the site itself. Concerning this point, I would like to point out to readers that the address of our site reported in ICUMSA News No. 39 was not complete; the exact address is www.unife.it/icumsa. In this site, on the page “Publications”, you will find the new prices in EURO and the conditions of purchase. Such information can also be found at the page “books” of the Zuckerindustrie magazine website (www.bartens.com). We hope that there will be a wide circulation of the Proceedings and other ICUMSA publications, in particular the Methods Book, not only to emphasing the importance of our Commission, but also to allow the Treasurer to improve ICUMSA’s bank balance, which has incurred some heavy expenditure due to the publication of the Proceedings and the moving of the management from IML to Zuckerindustrie. In this regard I would like to remind those National Committees, who have not already paid their subscriptions, that these are now due for payment.
Mr. John Dutton, in cooperation with the various Referees, is preparing the 2000 Supplement of the ICUMSA Methods Book which should include twelve new Methods, three revised Methods and one rewritten Method. Thist should be available within the end of this year.
The initiative of clearing the stock of old ICUMSA publications by offering them to non-profit organizations and public libraries for the cost of postage and packaging has not been successful.
In fact, we only received one request and it was not possible to fulfil this as such an initiative needs a minimum number of applications to be economically feasible.
Up until now I have not received any reactions to the different points raised in the last ICUMSA News. Of course, all comments and suggestions will be welcome (e-mail: email@example.com; Fax: +39 532 291168).
Activity within General Subject 8:
Beet sugar Processing
Jean-Pierre Lescure (France), Referee for General Subject 8
Discussions inside the General Subject 8 were organised by the Referee on the three main points:
I – Chromatographic Methods:
It is not the purpose of the Referee to interfere with the Subject 8, “Chromatographic Techniques for Sugars”, but the French and the German Committees agree that there is a strong evidence that HPAEC methods for sugars and related composites could be useful in process analysis. However, though they are widely used as research methods they have found no application into factories. It makes no sense for ICUMSA to invest work in techniques which are possibly too complex to introduce them in common practice.
II- Enzymatic Methods:
According to Mr P. BURROUGHS and Dr THIELECKE the simplicity of the various kits’ commercially available today makes them particularly attractive for non-routine analysis e.g. project work or process trouble shooting work on a factory site. The various enzymatic methods as offered by the former Boehringer Mannheim branch of Roche usually are well described by the manufacturer. Very little is required in the way of reagents and apart from a spectrophotometer very little instrumentation is required. There may be some difficult matrices such as beet, raw juice and molasses which need a special sample preparation procedure. How should such samples be preserved for collaborative study? Any preserving methods might interfere with the enzymes. To find out these special cases could be an object of further studies.
Generally, the status Accepted might do for internally applied enzymatic methods. The French Group gave a contribution on these methods for the last Session in Berlin. There is no more particular need to convert them to Official Methods.
The potential for dextran to cause filtration difficulties in factories following frost damage to the beet is always of concern. It would be interesting to have more simple methods to identify the presence of dextran in process juices.
Mr ROUSSEAU said that Saint Louis Sucre was working on frozen beet and dextran analysis by double hydrolysis. He could not produce details on the progress of the work, but he was interested in direct exchanges on the subject.
The main work in this area was made by the German Committee.
According to Dr THIELECKE in the case of dextran determination after hydrolysis and indirect estimation via accompanying substances the following should be considered:
– Enzymatic dextran hydrolysis is not complete, branched partitions are not attacked by common dextranases. This point has been criticised as crucial by some experts.
– It has been found that even essentially undamaged beet can contain mannitol quantities. The threshold values of mannitol and/or leucrose for factory problems have still to be studied.
This can only be done in the campaign after thawing of frozen beet, an event which fortunately does not happen too frequently in our region.
– There is no immediate need to organise any collaborative work at present.
– Several points need further studies, the Referee is always willing to receive contributions from Associate Referees or from anybody else on these subjects.
ICUMSA Subject 2:
„Oligosaccharides and Polysaccharides“, Interim Report
Klaus Thielecke (Germany), Referee for Subject 2
The Report of the 22nd Session of ICUMSA was published in May 2000 and is available now. This should lead to an effective impulse on the working programs of all Subjects. For Subject 2 the Referee should like to mention the following progress regarding the Recommendations of the 22nd Session in Berlin:
The Official HPAEC method for the determination of raffinose in beet molasses and juices published in the 1998 Proceedings has been re-written in a format suited for the ICUMSA Methods Book. The method will be edited as ICUMSA Standard GS4/8-19 by the Publications Committee.
In Subject 2 lactose was used as internal standard for HPAEC determination of oligosaccharides.
Leucrose and melezitose were recommended also in cases of bad separation of lactose and sucrose. Gillian Eggleston then introduced glucosamine HCl as internal standard for the separation of fructose, glucose and sucrose (SPRI 1998), and communicated the importance of the bracketing method with check standards. The Referee proposes to compare these and maybe other internal standards applied on different matrices in order to find out the best all-round solution.
At the Berlin Session the HPAEC method in general was accepted as an analytical standard method for oligosaccharide analyses. Following this line, the Publications Committee proposed to create a standard GS4/8-20 „Oligosaccharides other than raffinose in beet molasses and juices by HPAEC“. Because the laboratories of the Referee lack sufficient experience in this field the Associate Referees were asked for contributions to this topic. There is strong evidence that the above mentioned raffinose method can be extended to other important oligosaccharides and related compounds (kestoses, stachyose, galactinol etc.) after a modest modification.
The availability of pure oligosaccharides for chromatographic standardisation is still poor. As far as known there are commercial supply sources for fructosyl nystose, 1-kestose, nystose and raffinose. Gillian Eggleston mentioned a Japanese source for theanderose (Wako Chemicals) but found that the purity was disappointing (about 50 %). The Referee asked the Associate Referees to inform him on any sources for beet and cane oligosaccharides besides the already mentioned commercial sugar standards, because he intends to set up a list of supply sources. Relevant building blocks of polysaccharides needed as standard (e.g. isomaltose) also should be regarded in this context.
Some colleagues were interested in the HPAEC dextran determination after cleavage with dextranase according to B. Zimmer (ICUMSA 1998, CITS 1999), and in the determination of the degree of beet alteration via microbial metabolites (leucrose or mannitol) according to K. Steinmetz and R. Buczys (ICUMSA 1998). The best choice for an analytically suited dextranase should be studied further in this connection.
Mannitol can be determined by HPAEC as well as enzymatically with NAD/mannitol dehydrogenase. Rolf Lemmes contributed a campaign study on the adverse effects of dextran on beet sugar manufacture via leucrose and mannitol determination. Other potential metabolite markers in deteriorated cane have been reported (isomaltotriose, palatinose).Though a collaborative test of these methods will be problematical, because deteriorated (beet) material must be produced and stabilised artificially, the Referee intends to derive the method procedures from the original publications and to arrange a collaborative test in this field, if sufficient laboratories are interested.
The photometric pectin determination in beet juices with m-hydroxy diphenyl as colour reagent was re-examined by the Turkish colleagues. Their initial results were somewhat disappointing, and it turned out that the method seems to be not easy to perform under practical aspects. In consequence this group proposed to develop an HPLC method for pectic substances without dealing with a defined procedure.
However, it should be remembered that the determination of pectin had been left aside in Subject 2 at the last Session. Therefore, any efforts to re-animate further studies in this field should be examined thoroughly in view of a well-founded interest of ICUMSA. The Referee will decide on further consideration of this topic after expression of the other
Associate Referee’s opinion.
The application of the HPAEC/PAD technique on short chain oligosaccharides (DP < 3) was criticized by Dierk Martin, because in his opinion it tends to change reproducibility and large differences in response factors. The latter drawback forces the analyst to run analytically pure standards, which are available only in a limited manner as said above. He informed the Referee that, by these reasons, his group prefers a G.L.C. technique for the determination of oligosaccharides. If these experiences should reflect a general trend in saccharide analysis the dominating role of HPAEC in this field must be re-evaluated in future.
The Referee should like to remind the Associate Referees to examine their address and tele-communication entries as well as their official function for ICUMSA in the web site „unife.it/icumsa/“. This pre-requisite turned out to be a crucial point for an unhindered communication not only within this Subject, but elsewhere.