26th ICUMSA Session 2008

Final Recommendations

GS1 Raw Sugar – Referee: R. M. Urquhart (Australia)

1.   The starch method GS1-16 to be modified (see Appendix 2) to include the use a 100ml Kohlrausch flask, duplicate determinations on the moisture in the potato starch, a change to the source of the potato starch and inclusion of the precision data obtained in the collaborative trial.

2.   Method GS1-16 be given Official status for the analysis of starch in raw sugar.

3.   Work should proceed on collaborative testing a method for the analysis of fine grain, mean aperture (MA) and coefficient of variation CV in raw sugar. This could include collaborative testing of the tentative method GS1- 20 or another method.

4.   Make the corrections to various GS1 Methods as outlined in Appendix 2.

GS2 White Sugar – Referee: K. E. Pardoe (UK)

1.   ICUMSA Draft Method No. 7 (2006), The Determination of Arsenic, Cadmium, Copper and Iron in White Sugar by Atomic Absorption Spectroscopy cannot be adopted without further testing to prove its utility. The requirement for use of air, as part of the furnace program, restricts the use of this method to very few laboratories. Further testing of analysis of white sugar by HGA should involve the use of the digestion procedure used in Method GS2/3-24 (1998) and the target metals cadmium, copper, iron and lead.

2.   The Analysis of Arsenic in White Sugar by hydride generation should be developed and collaboratively tested.

3.   Investigate the effect of cell path length and type on the turbidity of White Sugar using Method GS2/3-18 (The Determination of Turbidity of White Sugar Solutions).

GS3 Specialty Sugars – Referee: G. Negbenebor (UK)

1.   ICUMSA Method GS4/3-13, The Determination of Refractometric Dry Substance (RDS %) of Molasses and Very Pure Syrups (Liquid Sugars), should be officially adopted for GS3 liquid sucrose refractometric dry substance determinations.

GS4 Molasses – Referee: G. Eggleston (UK)

1.   Continue studies on the Draft Method 8 “The Determination of Apparent Total Sucrose from Sucrose, Glucose, and Fructose in Molasses by an Enzymatic Method.” Improve the stability and shelf-life of the enzymes.

2.   Investigate the possible use of NIR spectroscopy for routine monitoring of molasses.  Intra-laboratory studies need to be investigated with Subject 6 “Indirect Methods of Analysis” as inter-laboratory, collaborative studies would be difficult.

GS5 Cane – Referee: G. S. C. Rao (India)

not present

No Report, No Recommendations

GS6 Beet – Referee: D. Martin (Germany)

1.   All Recommendations were implemented and currently no further working program has been identified. Therefore the Referee suggests keeping GS 6 in dormant condition until new proposals have been submitted.

GS7 Cane Sugar Processing – Referee: M. B. Londhe (India),

not present, presented by S. S. Nimbalkar (India)

1.   The work on use of NIR polarimetric techniques for determination of polarisation is to be expedited

2.   The proposed method for MA& CV in massecuite sample is to be further studied for replacement of methanol.

3.   It is recommended to extend the scope of method GS1/3-7 (2002) for cane sugar processing products making necessary changes in sample preparation after further collaborative studies.

4.   Editorial changes in sample preparation of method GS2/1/7-33 is to be done for cane juice and syrups – 1 to 5g instead of 5g sample and status of the method shall be continued as ‘Accepted’.

GS8 Beet Sugar Processing – Referee: J. M. Huet (France), supplemented by R. Lemmes (Germany)

1.   The method GS 8-19 (2008): “The determination of Higher Molecular Mass Substances in Beet Raw Juice and Thick Juice by a modified Alcohol Haze Method”, should be adopted with the status “Tentative Method”.

2.   Draft Method No. 3 (2007) “The determination of starch in Cane Sugar Products and Beet Juices – VSI method” should not be applied to beet juices analysis.

3.   Draft method: “The Determination of Mannitol in Beet Juices, Thin Juices and Syrups by an Enzymatic Method” – (2008) should be adopted with the status “Tentative Method”.

4.   Study further oxalic acid content measurements in thin juices, syrups and thick juices by an enzymatic or complexometric method.

5.   The applicability of the existing ICUMSA Method GS4/3-13 (2007) “The Determination of Refractometric Dry Substance (RDS %) of Molasses and Very Pure Syrups (Liquid Sugars)” should be extended to thick juice and run-off syrups as an Official method. Precision data obtained in the study described here should be added to the Method description. It should be noted, that the Method has Accepted Status for Molasses and Official Status for Very Pure Syrups.

6.   Based on a comparison of the precision data, it is recommended to give the proposed method for polarisation measurement applying Carrez clarification (modification of the raw sugar polarisation method GS1/2/3/9-1 (2007)) official status for beet sugar juices.

7.   The influence of clarification on the trueness of results should be further studied.

GS9 Plantation White Sugar – Referee: V. S. Keskar (India)

1.   Based on the Results of the studies shown in the Report, it is recommended to re-validate Method GS2/3/7/8 with the proposed modifications for white sugar, specialty sugars, and PWS.

2.   Studies on the modification on GS2/3–29 should be continued to accommodate Plantation White Sugar with appropriate sample preparation procedure.

3.   Editorial changes in Method no. GS 2/1/7-33 should be done to accommodate Plantation White Sugar.

4.   Editorial changes in Method no. GS 2/3-17 should be done to accommodate Plantation White Sugar.

S1 Constitution and by Laws – Referee: G. Parkin (UK)

1.   The revised text of clause 1 of Article I of the By-Laws, as described during Subject 1 Report of the 25th Session, shall be put before the Executive Committee Meeting and voted upon.

2.   The revised text of clause 5 of Article III of the Constitution, as specified in this Report, shall be put before the Executive Committee Meeting and voted upon.

S2 Oligosaccharides and Polysaccharides – Referee: M. Wojtczak (Poland)

1.   Method GS1/2/9-15 should be rewritten with the proper precision data for white sugar and plantation white sugar, given in Table 1 of this report.

2.   The four methods for the determination of starch (GS1-16, GS1-17, Draft No 3 and Draft No 4) should be tested together in one collaborative test to choose the best one.

3.   The study of the method for the determination of mannitol in beet brei and beet juices by HPAEC method (Draft No 1) should be continued in Subject 2.

S3 Method Format, Collaborative Testing and Statistical Treatment of Data – Referee: M. A. Godshall (USA)

No Report, No Recommendations

S4 Density, Optical Rotation and Refractive Index – Referee: M. Kuchejda (Germany)

1.   SPS-1, 3.3 should be amended as follows: For quartz wedge instruments the effective wavelengths have been fixed at 587.000 nm or/and 882.600 nm.

S5 Dry Substance – Referee: S. K. Gupta (India), not present

Report not presented, no Recommendations adopted

S6 Indirect Methods of Analysis – Referee: L. A. Edye (Australia), not present

No Report, No Recommendations

S7 Colour, Turbidity and Reflectance Measurement – Referee: C. Lakenbrink (Germany) presented by H. Puke (Germany)

1.   It is recommended to verify the adapted reflectance ratios for the ceramic tiles given in Table 1 of this report by a further collaborative test so that calibration of reflexometers with ceramic tiles will yield comparable results for the colour-type of sugar samples as the calibration with sugar standards.

2.   It is recommended to approach the PTB with the aim to nominate the PTB in ICUMSA Method GS2-13 as independent institution for calibration of the ceramic tile standards.

3.   Additional Recommendation given by the Indian National Committee:

      It is recommended to conduct an international collaborative study on the method proposed by INC at pH 6.4 with MOPS buffer along with existing colour method GS9/1/2/3-8 with white sugar, plantation white sugar and other types of sugars with wide colour range.

S8/9 Chromatographic Techniques – Referee: B. White (USA), not present

No Report, No Recommendations

S10 Enzymatic and Immunological Methods – Referee: L. Corcodel (La Réunion)

1.   Continue the work conduct on enzymatic measurement in other General Subjects.

S12 Microbiology – Referee: M. Jacobs (Germany), presented by M. Bruhns (Germany)

1.   The determination of osmotolerant yeasts should be collaboratively tested with a homogeneously contaminated sugar sample.

S13 Reducing Sugars – Referee: G. Sezer (Turkey), presented by H. Puke (Germany)

No Recommendations

S14 Ash – Referee: J.-P. Ducatillon (France), not present

No Report, No Recommendations