ICUMSA News n°3 – 1988


The serious work of the 20th Session is now underway after a slower than usual start. This of course was the consequence of the reorganisation of subjects with the need to reallocate the recommendations of the 19th Session. By this time everyone who has a desire to serve will have indicated the subjects to which they wish to contribute as Associate Referees. The complete list of Associate Referees with addresses is available from National Committees, Referees and the General Secretary.

Reallocation of 19th Session Recommendations

The Steering Committee comprising Dr. A. Emmerich, Mr. J.V. Dutton, Dr. M.A. Clarke and the President have now considered the many submissions made about reallocation of the 19th Session Recommendations to the new list of subjects.

It was not a simple task to allocate recommendations among the new subjects and obtain a perfect fit. The reason for this difficulty lies in the change in philosophy adopted for the 20th Session. The General Refereeships are expected to reflect the needs of the marketplace and if a recommendation does not appear to have relevance to one of the General Referees’ subjects then one must question whether the recommendation should be pursued. In a few cases 19th Session Recommendations remain unallocated because appropriate referees could not be found. The reallocation of Recommendations has been prepared in tabular form and these have already been distributed to Referees and the Chairman of National Committees from whom copies may be obtained.

New Methods Books

The Chairman of the Publications Committee, Mr. Dutton, has advised that his committee is now ready to undertake the publication of methods for a new book. The President’s view on the form of this book was set out in the Special Committee’s reform proposals in 1986. This involved the publication of individual methods as booklets which could be distributed individually or else combined in a suitable binder. A format similar to that used for ISO methods would be adopted so that mutual recognition of methods between organizations would be facilitated. Methods could be sold by the Publications Department at a price designed to recover costs but based on the number of pages involved. The status of a method, official or tentative, would be indicated in its title. As methods are upgraded, new booklets would be produced to contain any changes involved. In this way a collection of methods could be continually kept up to date by simply purchasing new method booklets as they were issued.

Method Reviews by General Referees

At the request of the President, General Referees have reviewed the analytical methods used by commerce and industry in their particular subjects. One of the results of this exercise is to show where there is duplication of methods between competing organizations and where commercial methods do not yet exist. It is to be hoped that discussion between the various interested parties will resolve issues revealed in this review. The methods used for the analysis of molasses, white sugar and raw sugar are discussed in this issue.

Molasses Analysis

The General Referee, Mr. D.S. Martin, has reviewed the methods used for analysing molasses. Dry matter or water content uses the vacuum drying method but there are competing methods emerging. One is the Karl Fischer method which needs inter-laboratory testing while near infra-red analysis holds some promise of a very rapid determination but requires further development. The determination of total sugars as reducing substance also has alternative methods to the Lane and Eynon constant volume method: The Luff- Schoorl method is used by some organizations while HPLC and enzymatic methods hold great promise but need further development. Total mineral matter is determined as sulphated ash while individual cations are determined by atomic absorption methods.

There is a need for methods to measure total fermentable compounds, rheology and colour although in the latter case, the specification of a methodology suitable for molasses is all that is required.

White Sugar

The methods required for white sugar have been reviewed by the General Referee, Dr. Charles Harvey who also reports on the priorities he has set for work leading up to the next Session in 1990.

The methods required by the Codex Standard for White Sugar, the European Economic Community legislation, the European Pharmacopoeia specification for sucrose and the requirements of commercial users and producer of white sugar have been assembled and divided into high and medium priority lists shown in Tables 1 and 2.

The high priority list includes all the methods required by the Codex Standard for White Sugar, those procedures for which there is an EEC statutory specification and those methods for quality parameters regarded as essential by commercial users. Commercial users ‘and producers’ specifications for white sugar may include other parameters, such as pesticide residues, gravimetric ash and radionuclides. These additional requirements are in the medium priority list.

The high priority methods are thought to be of fundamental importance to users and producers of white sugar and are essential for the quality assurance of the product.

Table 1: Methods required by legislation and commerce needing high priority attention by ICUMSA

Parameter ICUMSA Method Status Other organizations specifying
Polarization Proc. 1982, Subj. 19, p 341 Tentative
ICUMSA *, p 23 TentativeX
Reducing sugars < 0.04 % ICUMSA, p59 Official X
Reducing sugars > 0.04 % ICUMSA, p55 Official X
Loss on drying Proc. 1986, Subj. 19, Rec 1 Official X
Solution colour Proc. 1978, Subj. 22. p 343 Official X
Sulphur dioxide ICUMSA, p98 Official X
Visual appearance Proc. 1982, Subj. 22A, Rec 4 Official X
Conductivity ash ICUMSA, p 85 Official X
Arsenic Proc. 1978, Subj. 17, Rec 4 Official X
Lead ICUMSA, p92 Official X
Copper ICUMSA, p90 Tentative X
Particle size Proc. 1986, Subj. 19, Rec 3 Tentative   X 
Microbiological tests ICUMSA Official + Tentative   X 
Solution turbidity No method X
Insoluble matter ICUMSA, p 187 Tentative X

* ICUMSA = ICUMSA “Methods of Analysis”, ed. by F. Schneider, 1979

A = Codex Alimentarius; B = EEC Legislation; C = European Pharmacopeia; D = Customer or Manufacturer Specification

Table 2: Methods required by legislation and commerce needing medium priority attention but for which there is no ICUMSA method

ParameterOrganization specifying
Foreign colouring matter (blueing agents)European Pharmacopeia
Gravimetric ashEuropean Pharmacopeia
Acidity I AlkalinityEuropean Pharmacopeia
BariumEuropean Pharmacopeia
DextrinsEuropean Pharmacopeia

Validation of Existing ICUMSA Procedures

Over the years, ICUMSA has published many of the methods listed, either in the ‘Method of Analysis’ book or in later Proceedings; some methods have attained ‘Official’ status whereas others remain ‘Tentative’. At the last Session in Cannes, considerable emphasis was placed on the need for ICUMSA methods to be validated by collaborative testing so that they are readily acceptable by other organizations such as ISO and AOAC. Dr. Clarke’s working group on this subject has recommended that all ICUMSA’s methods be validated to IUPAC standards.

An additional incentive toward validation is provided by the current Codex review of standard methods for white sugar. The Codex Committee for Methods and Sampling requires evidence that methods have been fully tested and may not accept ICUMSA methods without this validation.

Raw Sugar

The General Referee for Raw Sugar, Mr. R.J. McCowage, has reviewed the methods of analysis for raw sugar and set priorities for work for the current session. Raw sugar is a commodity which is handled, transported and stored as an intermediate product, not a foodstuff. Legislative bodies have to date shown little interest in it, primarily focusing their attention on white or refined sugars which are intended for human consumption, either directly or indirectly. The Codex Co-ordinating Committee for Latin America and the Caribbean expressed some interest in establishing a standard for raw sugar at its meetings in 1984 and 1985. However, while the 17th Session of the Codex Alimentarius Commission held in Paris in 1987 resolved that a draft standard should be produced, this has not yet appeared and is likely to be limited to raw sugar intended for direct human consumption.

Thus, with no legislative provisions relating to raw sugars, the highest priority for the General Refereeship for Raw Sugar concerns methods of analysis required in commerce. These are methods which form the basis for payment and/or product specification. At a slightly lower level of priority are methods used to assess particular quality attributes of raw sugars which are of significance to refiners, but which do not impact on terms of trade. These primarily relate to processing characteristics but can also cover trace levels of impurities which can pass through a refinery into refined sugars and other products.

Methods used in raw sugar trade

Table 3: Methods required by commerce and industry needing high priority attention by ICUMSA

ParameterICUMSA MethodStatus
PolarizationICUMSA*, p 25+Official
Reducing sugarsICUMSA, p55Official
ICUMSA, p57Official
Sulphated ashICUMSA, p 83+Official
Conductivity ashICUMSA, p85Official
Proc. 1982, Subj. 16, p 278Official
Moisture Proc. 1986, Subj. 13, Rec 5Tentative
Colour ICUMSA, p 125Official
pH ICUMS A, p 132Official
Fine grain No method
Dextran No method
Standard Affination No method
Temperature No method

* ICUMSA = ICUMSA “Methods of Analysis”, ed. by F. Schneider, 1979

+ plus amendments

The high priority methods set out in Table 3 are those which are currently used in the international trade of raw sugars, either to establish base value or to apply quality incentives. Both the London Commodity Exchange Raw Sugar Contract No. 6 Rules and the New York Coffee, Sugar and Cocoa Exchange Contract No. 11 Rules, which apply to the world’s raw cane sugar futures trade, include no more than raw sugar polarization in description of payment conditions. Therefore, the polarization method is of prime importance in world commerce.

The New York Exchange Contract No. 14 Rules, which apply to US domestic production, specify Standard Quality Ranges in respect of moisture, ash, grain size, affined raw colour whole raw colour and dextran. These quality criteria have been adopted, either in the Contract No. 14 or in slightly amended form, in international sales contracts by a number of US refiners and have financial incentives associated with them. These methods are therefore of importance to raw cane sugar producers supplying the US market.

In the EEC beet raws trade there is an agreed formula for calculating net yield. This formula is based on raw sugar polarization, conductivity ash, and reducing sugars content. There are also specifications covering pH, reducing sugars content, temperature and security factor or moisture content. These methods are thus of fundamental importance to that trade.

Legislation in Europe and the United States appears likely to eventually preclude the use of lead. With the polarization test being the single most important analysis in the raw sugar trade, work to prove a new clarification agent for this procedure must assume a high priority. Of course, Subject Gl is not the only area in which this legislation will impact, making work on this problem extremely important for ICUMSA as a whole.

Methods used for quality checks

Methods used for quality checking do not appear in international sales contracts however they can be applied either routinely, to monitor raw sugar quality, or intermittently, to check on particular processing irregularities. A list of such methods appears in Table 4 where medium to low priority has been judged to be appropriate. This list is not exhaustive, and others may wish to include additional methods. Lists themselves are dynamic, changing as particular quality issues rise and decline in importance.

Table 4: Methods required by commerce and industry needing medium to low priority attention by ICUMSA

Parameter ICUMSA Method Status
Citric acid1ICUMSA*, p 110Official
ERHICUMSA, p 122Official
CalciumICUMSA, p 87Official
Crystal washICUMSA, p 191Official
ICUMSA, p 192Tentative
Crystal size and distributionICUMSA, p 182Tentative
Phosphate2Proc. 1986, Subj. 17, Rec 2Tentative
Buffer powerICUMSA, p 189Tentative
LeadICUMSA, p 91Tentative
StarchNo method
SulphiteNo method
Total polysaccharidesNo method
Insoluble mailerNo method
Solution turbidityNo method
FilterabilityNo method
Frothing propensityNo method
Crystal habit modifiersNo method

• ICUMSA = ICUMSA “Methods of Analysis”, ed. byF. Schneider, 1979

1 raw beet sugar

2 raw cane sugar

Editor: R. Pieck, Klein Spanuit 9, B-3300 Tienen, Belgien, April 1987. – Tel. +321 6/8 1 24 36 – Tx. 222 5 1 – Fax +321 6/82 03 17