ICUMSA News n°30 – 1997

Message from the President

On 12th June 1997 we celebrate the Centenary of our Commission. It will be 100 years since men gathered in Hamburg, Germany to discuss the desirability of forming an organisation with the objective of adopting uniform methods of analysis between nations trading in sugar. Every organisation has its heroes and the two most outstanding figures in ICUMSA must surely be Alexander Herzfeld and Frederick Bates.

Alexander Herzfeld provided resolute leadership to the fledgling Commission in the first 15 years of its founding. It is very significant that Frederick Bates, by virtue of his role in the US Bureau of Standards developed a lively interest in the work of ICUMSA in those early days. Even though the First World War interrupted the formal meetings of the Commission, its spirit was kept alive in the hearts of both Herzfeld and Bates. Indeed, some of the most significant work on polarimetry was conducted in the US Bureau of Standards during those war years.

It is sad that Herzfeld never reconvened ICUMSA after the first World War and it was only after his death that Bates did so in 1932 at a meeting in Amsterdam. The Bates presidency extended from 1932 to 1954 but it too was interrupted by the Second World War. Bates however, reconvened the Commission for the second time in 1949 and when it was again in robust health handed it over to Siegfried de Whalley in 1954.

ICUMSA has enjoyed nearly 50 years of uninterrupted activity since 1949. Through the leadership of five presidents – Siegfried de Whalley, Jean Dubourg, Albert Carruthers, Erich Reinefeld and Murray Player – the Commission has come of age. It adopted its Constitution and By-Laws in 1936 and has had formal printed Proceedings since then. Methods Books have been published in 1964, 1979 and 1994. Conferences have been held at regular intervals since the 1949 meeting in Brussels, Paris in 1954, Washington in 1958, Hamburg in 1962, Copenhagen in 1966, London in 1970, Ankara in 1974, Montreal in 1978, Dublin in 1982, Cannes in 1986, Colorado Springs in 1990 and Havana in 1994.

The real celebration of our Centenary will take place in Berlin from 24th to 29th May 1998. On the 18th March I met with the German National Committee at the Institute of Food Technology (formerly Berlin Sugar Institute) to discuss arrangements for next year’s meeting.

The 22nd Session will be held at the Steigenberger Hotel, Los Angeles Platz, right in the heart of Berlin. Delegates will visit the Sugar Museum and inspect the pilot plant size sugar factory at the Institute of Food Technology as guests of Professor Mauch. The Wednesday afternoon excursion will be to Sanssouci Castle at Potsdam with the return journey to Berlin being a boat ride on the rivers Havel and Spree with dinner being served on board.

Other Centenary events will involve the publication, later this year, of a history titled “ICUMSA History – The first 100 years” and the first supplement of the 1994 loose leaf Methods Book. Copies of the ICUMSA History may be reserved by ordering now at a prepublication discount price of £18 surface mail or £22.50 airmail from ICUMSA Publications Department.

To ensure the technical success of the Berlin Session, Referees are urged to submit their reports to the President before 31 December 1997. This will permit their circulation among the membership with sufficient time to ensure lively discussion.

A further innovation at the Berlin meeting will be a poster session. Delegates are invited to bring a poster illustrating new work or interesting data on any subject of relevance to the objects of ICUMSA. The posters will be hung on the walls of the conference venue and delegates will then have the opportunity to discuss their contents with the authors at coffee breaks, in the evenings or in other free time. It is hoped that through the posters some new ideas will be discussed that would not necessary have been dealt with in Referees’ reports.

The Chairman of the Nominations Committee, Professor Mantovani, has written to National Committees calling for provisional nominations for President upon being advised that I do not propose to offer myself for re-election at Berlin. It is envisaged that candidates will be given the opportunity to discuss their manifestos in the pages of future issues of ICUMSA News. To facilitate this process, nominations should be submitted to Professor Mantovani before 30 June 1997.

Progress Report for General Subject 7: Cane Sugar Processing

Dr. Owen Crees, Referee

Two issues were identified at the 1994 ICUMSA meeting in Havana for investigation within General Subject 7. The Cuban delegates indicated a need for microbiological methods for use in raw cane sugar mills. Other delegates promoted continuing investigation of non-toxic alternatives to lead clarifying agents for the polarimetric sucrose determination in various factory products.

Sucrose analysis

There has been extensive work reported in the literature on the use of various alternatives to basic lead acetate for the analysis of high d.s. material such as syrup, massecuite and molasses, as well as low purity materials such as final molasses.

Cuban scientists have reported an investigation of the use of CaO with Al2(SO4)3 to preserve and clarify raw juice, clear juice and filtrate. The results showed that CaO was an effective preservative for the samples, and that the reagents gave effective clarification over a wide range of conditions.

Investigations were carried out in Indonesia during 1995 using polyaluminium chloride as a clarifying agent for first expressed juice, mixed juice, clarified juice, syrup, massecuites and molasses. The results showed that for juices there was no significant difference between the results obtained with lead acetate and results obtained with polyaluminium chloride. However, the filtration rate was slower with polyaluminium chloride. The results with D massecuite and with A and final molasses showed significant differences, with the greatest difference being for the lowest purity materials. The difference was also high for A massecuite, despite the high purity. Again, filtration rates were lower than with lead acetate.

In Mauritius, it was found that the ABC reagent developed by Audubon Sugar Institute and marketed by Baddley Chemicals Inc. gave comparable results to lead acetate with juices and syrups. However, color removal was poor with dark solutions such as final molasses. Unpublished data on juice analyses from Australia showed satisfactory results using Celite filtration to clarify juices for analysis in a polarimeter operating at 880 nm.

It appears that, for juices and raw sugar, there are other clarifying agents which give results that are not significantly different from those obtained with lead acetate. Unfortunately, however, there does not appear to be a viable alternative for high d.s. or low purity materials such as massecuites and molasses. There is considerable interest in many countries in developing alternative procedures which will enable lead compounds to be eliminated from the laboratory. While no collaborative testing is being carried out, several groups are continuing active investigations of new methods suitable for all factory products from juice through to final molasses.

Microbiological analysis

The Referee for Subject 14 – Microbiology – believes the existing ICUMSA pour plate methods for microbiological analyses of refined sugars (GS2/3-43, GS2/3-45, GS2/3-47, GS2/3-49) could be used for cane juice. A survey of Associate Referees indicates that there is very little need for separate microbiological methods for cane juice or other processing products. It is generally accepted that determination of lactic acid as an indicator of the extent of microbial activity is simpler and quicker than detailed microbial analysis. There is insufficient support to justify a separate investigation by ICUMSA General Subject 7.

Progress Report for Subject 9: Chromatographic Techniques for Non-Sugars

Dr. Paul Bourlet, Referee

Work for Subject 9 was initiated somewhat late due to changes in the organisation of our activities and I must apologise for not having undertaken it before. Regarding the Recommendations adopted at the last Session in Havana the following conclusions can be drawn:

Recommendation 1, Inorganic Anions. Analysis of the inorganic anions in sugars has not been defined as a priority analysis by any of the Referees of General Subject 1 or 2, so that no work has been undertaken in this field.

Nevertheless, it must be pointed out that although this analysis is not of the greatest importance in order to determine the quality of the white sugar which has just been produced, it can show evidence of contamination when sugar has been conveyed, by sea for example. With regard to this point, HPIC analysis is a very powerful tool and has been in use in the Referee’s laboratory now for several years.

Chloride is determined using a Dionex AS4A column together with an AG4A precolumn, the eluent is a mixture of Na2CO3 (1.8 mM) and NaHCO3 (1.7 mM) at a flowrate of 1.5 ml/min and sodium is measured by flame emission spectroscopy.

Recommendation 2, Sulphite. This Recommendation was essentially designed for the analysis of sulphite in molasses. It appears that the development of a new method of analysis is not necessary at this time so that work on this point has been postponed.

Recommendation 3, Organic Acids. This Recommendation deals with the analysis of organic acids in factory products. As could be seen during the last Session, a large number of acids can be investigated by using two main techniques: HPLC and HPIC.

Every factory technologist has developed his own method of analysis but the number of laboratories using the same technique seems too limited in order to propose a ring test. The aim of doing such analysis is in fact very specific to each situation and it does not seem that a general method could bring something new and sufficiently comprehensive to cover these specific purposes.

Recommendation 4, Betaine. Betaine analysis is the subject which seemed most suitable for the planning of a ring test because some important improvements have been drawn up since the last Session. The point concerning the elimination of glutamine was settled and a well-defined method has been presented by K. Thielecke.

Betaine is determined on a cation exchange column in the calcium form at 85 °C with destilled water as eluent. Two columns prove to give quite equivalent results

– Brownlee Polypore Ca, 220 x 4.6 mm, 10 m, Alltech

– Bio-Rad Aminex Carbohydrate HPX 87-C, 300 x 7.8mm

Two methods are proposed to eliminate the glutamine in beet brei and beet juices: Deamination with L-asparaginase (Braunschweig Institute) or with formaldehyde (IRIS). Both methods give good results and take less than one hour of reaction time.

A circular letter was therefore sent to each Associate Referee of Subject 9 in October 1996. At the present time some answers have been received. Five laboratories can analyse betaine using the proposed method. Five other laboratories use HPLC cation exchange columns in a monovalent cation form: HPX 87-N, HPX 87-K. Two laboratories use columns that are not known by the referee.

As the number of eight laboratories cannot be reached, it is not possible, at this time to carry out a full-scale collaborative evaluation. However, there is a need to get more information about the accuracy and repeatability of these methods using columns in a monovalent cation form in order to determine if they can give rise to a more general procedure for the determination of betaine. Therefore, I appeal to anyone having an interest in such analysis to contact me by fax (+33 3 20 47 09 10) if they want to be included in a collaborative study. Reply please by 30 June 1997 or earlier, if possible.

Failing this, a preliminary collaborative study should be carried out by the laboratories already mentioned, on a limited number of samples, in order to assess accuracy, repeatability and whether a more general procedure might be feasible.

Recommendation 5, Capillary Electrophoresis and Isotachophoresis.

New developments concerning capillary electrophoresis and isotachophoresis remain of prime interest as they can facilitate the analysis of some organic acids with minimal sample preparation and a short analysis time thus making this type of analysis very attractive.

The points made above show how difficult it is to propose a new method of analysis when it falls in the area of technical practice. Nevertheless, these methods, in particular for betaine, are important and still need to be developed. Any contributions in this area could greatly improve the technical control of factory processes as well as the evaluation of raw materials or the end products. Moreover, it needs to be emphasised that the ICUMSA Methods Book does not currently include even a Tentative method for betaine determination.

Determination of glucuse and fructose by HPAEC

Kevin Schäffler, Referee Subject 8

In my last communication I appealed for collaborators to test the HPAEC (HPLC) method for determining low levels of glucose and fructose in white and raw sugar. I have obtained a reasonable response and I’m extremely grateful to the people who are prepared to participate.

I’m now making a special appeal to those who do have HPAEC facilities and have not yet offered to participate. Please come forward and offer to participate. We will be collaborating with Subject 15 (Reducing sugars) and General Subject 2 (White Sugar). Comparative data between HPLC and Knight/Allen and other established methods will therefore become available. I realise times are tough and short-term business is “the name of the game”. However, if ICUMSA is to survive and introduce new accurate methods, then your help is imperative. Time is marching on, the procedure is not difficult and should take one to two weeks maximum.

Please let me know by fax or E-mail if you are willing to take part.

Kevin Schäffler, Fax: +27 31 261 6886, E-mail

Editor: Rud Frik Madsen, Strandpromenaden 38, DK-4900 Nakskov, Denmark – Phone +4553921675; Fax +4554951675; E-mail