28th ICUMSA Session 2021

Final Recommendations

General Subject 1,  Raw Sugar –
Referee: Andrew Harrison, Australia

1. The Method GS1-17 “The Determination of Starch in Raw Sugar by the SPRI Rapid Starch Test” should be given the status Official.

2. The Scope of Method GS1-16 should be modified to incorporate the Limit of Quantification to less than 300 mg/kg.

3. The Scope of Method GS1-17 should be modified to incorporate the Limit of Quantification to 300 to 1000 mg/kg.

4. It is acknowledged that recommendations 2 and 3 are compromises reached to provide the sugar trade with clear direction for dispute resolution until further information is available. It is therefore recommended that further work be done which focuses on identifying the underlying differences between the methods.

5. By Gillian Eggleston: Write the method titled: “The Determination of Commercial Amylase Activity by a Spectrophotometric Method” into ICUMSA format and publish as Tentative for 3 months with the validation data. Based on feedback then put to a postal vote for Official status.

General Subject 2, White Sugar –
Referee: Karen Pardoe, UK

1. GS2 Referee to prepare a document that outlines a set of guidelines for recommended sample preparation and instrumental analysis details suitable for the analysis of As, Cd, Cu, Fe and Pb in white sugar based on the collaborative study results.  This document will then be provided to study participants and Associate Referees for approval as an Official Method.

2. Once the document from Recommendation 1 is approved for use, the GS2 Referee will recommend a change in SUPS to reflect the new method. This will then mean the current SUPS metal contaminants sample is suitable for assurance/validation of laboratories testing white sugar according to the guidelines prescribed in the new method.

3. Update Method GS2/3-18 to recommend the use of a 10 cm cell with the provision that the minimum acceptable length is 5 cm.

4. Gain confirmation of supply of ABF positive beet and cane sugar in order to collaboratively test the methods proposed by J Jensen (Nordic Sugar) and M McKee (SPRI) alongside the current ICUMSA methods for Acid Beverage Floc (GS2/3-40 Parts A and B).

5. By Gillian Eggleston: Prepare an ICUMSA Tentative Method: “The Determination of Carry-over Amylase Activity in Raw and White Refined Cane Sugars by a Spectrophotometric Method”.

General Subject 3, Specialty Sugars –
Referee: Niels Kau Anderson, Denmark

1. It is suggested to carry out an assessment of suitable methods for analyzing SO2 in brown sugar. Furthermore it is suggested to carry out a collaborative study of the available methods in order to determine the best suited method for specialty sugars. GS1 (raw sugar) is to be included into this study.

2. The “HPLC Method for Determination of Total Sugar Content in Invert Sugar Syrups” should become an Official method.

General Subject  4 Molasses –
Referee: Gillian Eggleston, USA

1. Add precision data from the SUPS Testing Scheme to the end of Method GS4/7-1 “Apparent Sucrose in Molasses by a Double Polarisation Method”

2. Develop and evaluate a non-lead acetate method to replace Method GS4/7-1: “The Determination of Apparent Sucrose in Molasses by a Double Polarisation Method” using either:
An Aluminium compound,
Commercial clarification agent, e.g. Octopol™,
Carrez Solutions or
NIR polarimetry with filtration aid and filtration.

3. Develop and evaluate a non-lead acetate method to replace Method GS4/7-1: “The Determination of Apparent Sucrose in Molasses by a Double Polarisation Method”. If necessary, develop two methods – one for cane molasses, the other for beet molasses. Once a method or methods have been developed they should be collaboratively studied using an ICUMSA international ring test.

General Subject 6, Beet –
Referee: Dierk Martin, Germany

1. Further developments of methods for rapid determination of reducing sugar and other parameters which may become relevant for the description of beet quality should be observed. The transferability for the use in automated beet reception labs should be evaluated with regard to the required accuracy and precision, a high throughput of samples and a benefit-cost analysis.

General Subject 7, Cane Sugar Processing –
Referee: Arnaud Petit, La Reunion

1. A new method should be created: GS5/7-29 (2012) “The Determination of Pol (Polarisation), Brix and Fibre in Cane and Bagasse by the Wet Disintegrator Method with pressure filtration and near infra red polarimeter” –Tentative.

2. Collaborative tests should be performed on GS7-31 (2011) method: The determination of Pol by NIR Polarimetry and Brix for sugarcane and factory product – Tentative.

3. In table 1 of GS7-31 (2011), no dilution for cane analysis should be removed and replaced by 780g + 2080g.

4. In table 1 of GS7-31 (2011), pressed juice should be added next to mixed juice.

5. A new method should be created: GS5/7-30 (2012) “The Determination of Pol (Polarisation), Brix and Fibre in Cane by the Birding and Pollock method with pressure filtration and near infra red polarimeter” –Tentative.

6. A new method should be created: GS5/7-31 (2012) “The Determination of Pol (Polarisation), Brix and Fibre in Cane by the Holden method with pressure filtration and near infra red polarimeter” –Tentative.

General Subject 8, Beet Sugar Processing –
Referee: Jean Marc Huet, France

1. Withdraw Method GS 8/4-15 (1994): “The Determination of Raffinose and Kestoses in Beet Processing Samples by a TLC method” from the General Subject 8 methods’ list.

2. Withdraw Method GS 8-21 (1994): “The Determination of Dextran, Levan and Araban in Beet Juices and Molasses by a TLC Method” from the General Subject 8 methods’ list.

3. Continue studies for preparing a Tentative method: “The Determination of Dextranase Activity by a simple Titration Method” and for conducting intra-laboratory studies with Subject 6 “Indirect Methods of Analysis”.

General Subject 9, Plantation and Mill White Sugar –
Referee: Vasudha Shirish Keskar, India

1. The Method GS9-10(2011) “The Determination of (water soluble) Iron in Plantation White Sugar by a Colorimetric Method – Tentative” should be made Official.

2. The Method GS 9-9 (2011) “The Determination of Copper in Plantation White Sugar by Flame Atomic Absorption Spectroscopy – Tentative” should be made Official method.

3. Studies on development of methods for Zinc, Cadmium, Mercury and Arsenic in plantation white sugar using Atomic Absorption Spectroscopy and ICP techniques should be initiated.

Subject 1, Constitution and By-Laws –
Referee: Geoff Parkin, Germany

No Recommendations

Subject 2, Oligosaccharides and Polysaccharides –
Referee: Maciej Woitczak, Poland

1. The precision of the Method GS8-26 estimated during the collaborative study should be added to the method description as a text:
For raw juice mannitol contents from 30 to 200 mg/L the mean repeatability limit (P = 95%) has been estimated to be 11% and reproducibility limit (P = 95%) has been estimated to be 26% of the measured value.

2. The GS8-26 method description should be amended by the information about the possibility of interference of the mannitol peak by the formaldehyde peak.

3. The status of the Method GS8-26 “The Determination of Mannitol, Glucose, Fructose and Raffinose in Beet Juices by HPAEC-PAD” should be changed from Tentative to Official for mannitol and Accepted for glucose, fructose and raffinose.

Subject 4, Density, Optical Rotation and Refractive Index –
Referee: Mathis Kuchejda, Germany

1. There are potential errors associated with correct preparation of „normal sugar solutions“ between different users.
We have collected good experience by using gravimetric method for preparing normal sugar solutions: 100 °Z preparations with certified refined sugar can be routinely made with an error of less than ± 0,03 °Z.
The risk of handling errors are minimized.
Referees Proposal: A comparison between the official ICUMSA method and the proposed simplified method should be made in order to qualify the new method.

Subject 6, Indirect Methods of Analysis –
Referee: Amelia Andrade Ferraz, Denmark

1. It is recommended to form a multidisciplinary working group before the next ICUMSA meeting to develop general guidelines to be included in Subject 6 and to develop protocols for validating one or two Indirect Methods of Analysis already in use.

Subject 7, Colour, Turbidity and Reflectance Measurement –
Referee: Christiane Lakenbrink, Germany

1. The revised ICUMSA Method GS2-13 as presented during the Session should replace the current version in the ICUMSA Method book.

2. Adjustment to pH = 6.4 in ICUMSA MOPS buffer method does not result in any improvement of the precision of the method. From the results of the collaborative study there is no reason for changing the pH adjustment in ICUMSA Method GS9/1/2/3-8 from pH = 7.0 to pH = 6.4. It is recommended to keep Method GS9/1/2/3-8 as it is.

Subject 8/9, Chromatographic Techniques –
Referee: Niels Kau Andersen, Denmark

No recommendations

Subject 12, Microbiology –
Referee: Maritta Jacobs, Germany

1. ICUMSA Method GS2/3-50 (2012) The Determination of Thermophilic Acidophilic Bacteria (TAB) and Guaiacol-producing Alicyclobacillus strains in Sugar Products should be revised and should be checked by the microbiological laboratories of different sugar producers. The new method is Tentative until it is accepted in the next meeting.