NIR Polarimetry: A Viable Alternative for Juice. Marrington McDonald Sugar Industry Research Institute Kendal Road, Mandeville, Jamaica, W.I.

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1 NIR Polarimetry: A Viable Alternative for Juice Polarization Analysis Marrington McDonald Sugar Industry Research Institute Kendal Road, Mandeville, Jamaica, W.I. Annual JAST Conference 2005

2 Objectives Comprehensive evaluation of NIR Polarimetry. Determine Feasibility of the use of NIR Polarimetry in Juice Polarization in Jamaican mills.

3 Introduction Polarimeters provide a distinct advantage as they can be calibrated with certified standards. They provide reliable data on which cane payment and process control can be based. However standard polarimeters cannot However, standard polarimeters cannot analyze dark substances due to their operating wavelength.

4 Introduction cont d The use of chemical clarifiers facilitate utilizing standard polarimeters but chemicals impact negatively on cost and the environment. NIR polarimeters are developed to measure dark substances provided they are optically clear.

5 What is NIR Polarimetry? NIR refers to a specific range of wavelengths in the electromagnetic spectrum (usually nm). NIR is not a method but is used in a number of techniques such as spectroscopy, refractometry and polarimetry. Modern NIR polarimeters typically operate at nm.

6 NIR polarimetry Light waves at nm are able to pass through highly colored solutions because colored solutions do not absorb light at this wavelength. No color removal is required. The retention of all optically active components means that polarization correspond to a solution that is not altered chemically.

7 SacchAAr 880 Polarimeter Duplex high penetration polarimeter. It measures samples at standard nm and NIR (882.6 nm). Various measuring scales. Accuracy of ± angular degrees between 0-10º Z and for ISS ±0.01 between 0-25ºZ. Has the capacity to measure dextran and purity.

8 SacchAAr 880 Polarimeter Instrument has a stable quartz halogen lamp light source. Optical interference filters select wavelength. Calibration with standard quartz plate at nm. NIR calibration usually done with sucrose solution.

9 SIRI s Experience 2002 SIRI started work with NIR polarimeters. Work involved various phases:» Dextran analyses (juice, sugar and standards) ongoing»comparative dextran studies and Method Validation» Polarization analysis of sugars (ongoing)» Polarization analysis of juice

10 SIRI s Experience Dextran analyses» Work at Central lab and in the fields with a view to effectively evaluate method.» Comparative dextran study» Due to the emergence of a new method (Midland ) d ) and some inconsistent i t data this study was done. Challenges related to accuracy, precision and ambient conditions were encountered. Method Validation (DASA)» Done based on previous study and indicated method was imprecise but fairly accurate.

11 SIRI s Experience Juice Polarization» Main focus of this report and follows work at a Core lab A at the inception.» Current work done at two Core labs B and C.» Comparison between NIR method and current method (Octapol clarified).» Results indicate very good correlation between the two methods.

12 Results» At total t of f79t tests t were done at tlab bb over three days.» Results were analyzed in two sets.» Figure below shows plot for 42 data points (set 1). 880 nm pol vs 589 nm pol y = x R 2 = nm pol nm pol

13 Results cont d» The figure below shows plot for 37 data points (set 2 lab B).» A lower correlation coefficient is related to instrument instability (defective filter). 589nm pol vs 880 nm pol (Juice) y= x R 2 = nm pol nm pol

14 Results cont d» Two sets of data were also obtained from lab C.» The figure below shows plot for 125 data points (set 1). NIR pol vs 589 Pol y = x R 2 = m 589 n pol Pol NIR (880 nm) pol

15 Results cont d» The figure below shows the plot of 62 data points (set 2, lab C). NIR vs 589 nm pol y = x R 2 = nm po ol NIR pol Series1 Linear (Series1)

16 Results cont d» The figure below shows overall linear regression for 271 data points. Overall Linear Regression y = x R 2 = nm po ol nm pol

17 Statistical Analysis Lab Dataset R 2 Avg. Diff (ºZ) B B C C All All

18 Cost Analysis The following table outlines a ten-year cost comparison between the NIR and conventional methods. 1 Filter cel E 2 Octapol Method NIR ($) Conventional ($) Instrument 15,536, ,247, Reagents 6,840, ,000, Filter paper 8,100, ,100, Filtration 700, system Total ($) 31,176, ,347,500.00

19 Cost Analysis cont d Cost of NIR instrument is based on an Optical Activity quotation dated October 25, Cost of instrument for conventional method is based on current price of polaar 31 polarimeter. Cost of NIR reagent is based on current price ( 150/kg) of recommended filter aid. Cost of Octapol is based on 2004 figure. Cost of filter paper is current price. Total cost is calculated based on an average number of tests of 200,

20 Discussion & Conclusion Challenges related to the use of the method:» Method of filtration. This may be affected by quality of filter paper and filter aid used 4 by quality of filter paper and filter aid used 4.» Impact of ambient conditions. Several aspects of analytical procedure were evaluated.» Robustness» Ability to generate accurate, reproducible results under field conditions.

21 Discussion & Conclusion NIR polarimetry has multiple applications and based on the data presented it is a suitable and viable replacement for conventional methods of juice polarization. Investigation with dark products will continue throughout the 2005/2006 crop.

22 Acknowledgements The Director of SIRI and the JAST Secretariat for allowing the presentation of this report. Mr. Sydney Roman for analytical work. Dr. E. Roberts and Mr. J. Jaddoo for editing the paper. You, the audience, for listening so attentively.