Brewing Sugars and Syrups Subcommittee Members: Lydia Marinelli, Chairman; E. Austin, R. 2. It is recommended that the Subcommittee on Brewing Sugars Bogenrief, K. M. Brobsl, M. E. Cieslak, W. A. Davis, P. Fallen, M. Gray, and Syrups be retired. R. Hagy, A. M. Jamieson, K. Long, M. A. Mohs, P. M. Olinger, T. Otterson, A. F. Pomes, D. Schooley, H. D. Scobell, D. Stubbs, J. Whitt, and J. R. Helbert (ex officio). The evaluation of instrumental methods for determining CONCLUSIONS fermentable carbohydrates in brewing syrups was assigned to this Subcommittee in 1975. A collaborative study was undertaken in 1. The total laboratory error was lowest for glucose and maltose 1975-76 to evaluate two gas chromatographic methods and a high- using method 2, gas-liquid chromatography (GLC) of pressure liquid chromatographic method for determining glucose, trimethylsilyl (TMS) derivatives, when considering data for maltose, and triose concentrations in a pair of corn syrup samples. both types of syrups. The collaborative results (1) indicated that the least total error 2. The total laboratory error was lowest for maltotriose (triose) resulted from the use of the HPLC method. The highest error for all three methods was associated with the determination of triose using method 3, high-pressure liquid chromatography (HPLC), concentration. when considering data for both types of syrups. Based on recommendations evolving from the first collaborative 3. The total laboratory error was lowest using method 3, HPLC, study, a second collaborative study was initiated to include the when considering a combination of all three sugars and both following: types of syrups. 4. The coefficients of variation for total laboratory error using l.The same three methods, with minor revisions, would be method 2, GLC of TMS derivatives, ranged from 3.7 to 13.6 for evaluated. the individual sugars and from 2.0 to 5.5 for total fermentable 2. Standard sugars would be sent to collaborators. sugars. 5. The coefficients of variation for total laboratory error using 3. Two pairs of syrups, one with high glucose and low maltose and method 3, HPLC, ranged from 3.6 to 7.7 for the individual the other with low glucose and high maltose concentrations, sugars and from 3.5 to 3.8 for total fermentable sugars. would be included in the study. RECOMMENDATIONS COLLABORATIVE STUDY I. It is recommended that method 2, GLC of TMS derivatives (Appendix A), and method 3, HPLC (Appendix B), be accepted Two pairs of corn syrup samples were sent to each collaborator for publication in the ASBC Methods of Analysis. for the determination of glucose, maltose, and triose No. 3 ASBC JOURNAL 105 concentrations. Glucose and maltose standards were also supplied. calculating triose concentrations in the syrups. The syrups were to Since pure triose was not available commercially, collaborators be analyzed by one HPLC and two GLC methods, which were were instructed to use the response obtained for the maltose briefly described in the 1976 subcommittee report (1). Revisions standard modified by a factor unique to each method for submitted by the authors of the methods were included. TABLE I Carbohydrate Analysis by Method 1 (GLC of TMS-Oximes) (Expressed in g/100 g as-is) Glucose Maltose Maltotriose Collaborator/ Syrup A B C D A B C D A B C D 1 20.2 22.0 7.4 9.1 25.8 19.7 31.4 36.4 16.5 18.3 19.8 17.0 2 20.6 19.8 6.4 8.0 24.1 19.0 28.8 35.2 13.3 14.9 18.2 15.9 3 209 22 5 66 79 21 6 17.8 29.7 34.0 b b b b 4 18.4" 21.1" 5.8 7.5 22.5 18.0 23.6" 28. r 5.6 8.2 12.5 11.3 5 20.4 21.1 6.4 7.3 24.7 18.7 31.0 31.7 13.3 13.3 16.9 13.6 6 20.0 19.4 6.5 6.6 24.4 17.9 29.8 29.1 22.5 20.3 23.8 23.8 Mean' 20.42 20.96 6.52 7.73 23.85 18.52 30.14 33.28 14.24 15.00 18.24 16.32 Grand mean" 20.7 7.1 21.2 31.7 14.6 17.3 "Rejected as an outlier according to Dixon's test (p = 0.05) (2). hNo data reported. 'The mean does not include outliers. TABLE II Carbohydrate Analysis by Method 2 (GLC of TMS) (Expressed in g/100 g as-is) Glucose Maltose Maltotriose Collaborator/ Syrup A B C D A B C D A B C D 1 20.5 21.2 6.8 8.4 26.4 20.4 31.0 36.8 17.3 17.9 19.5 17.3 2 21.6 22.9 7.2 9.0 24.8 19.5 32.0 37.9 12.7 14.4 18.4 16.3 3 20.8 20.7 6.7 8.1 25.2 18.7 30.6 36.1 16.1 15.9 19.8 18.1 4 22.5 23.6 7.6 9.4 26.5 21.0 31.0 35.4 17.3 17.3 22.9" 19.4" 5 21.1 21.6 6.8 8.3 26.8 19.0 31.4 36.9 27.1" 25.0" 31.6" 29.1' 6 20.3 22.4 6.9 8.4 25.9 20.9 31.5 36.6 15.9 15.7 18.4 17.5 7 21.3 22.8 7.1 8.7 25.3 20.2 32.7 38.3 14.1 14.3 17.0 15.6 12 22.4 23.1 7.2 8.8 26.8 20.6 32.2 38.9 16.3 17.2 18.7 18.0 Mean1" 21.31 22.29 7.04 8.64 25.96 20.04 31.55 37.11 15.67 16.10 18.63 17.13 Grand meanb 21.,8 7.8 23.0 34..3 15.9 17.9 "Rejected as an outlier according to Dixon's test (p = 0.05) (2). 'The mean does not include outliers. TABLE III Carbohydrate Analysis by Method 3 (HPLC) (Expressed in g/100 g as-is) DPI DP2 DP3 Collaborator/ Syrup A B C D A B C D A B C D 1 20.7 21.9 6.7 8.2 26.7 20.7 31.9 37.6 16.5 17.3 19.3 16.8 2 22.9 22.6 7.4 9.6 24.3 18.0 25.3" 32.1" 16.1 14.9 15.7 17.5 3 20.9 21.7 6.5 8.3 26.6 20.7 31.8 37.5 15.6 15.9 18.2 16.6 6 19.3 21.0 6.2 7.7 24.6 19.7 30.2 35.4 15.1 15.6 18.0 16.1 7 20.0 20.6 7.1 8.3 27.1 21.6 33.7 38.7 16.9 17.4 18.7 16.1 8 20.1 21.7 6.6 8.0 25.8 19.2 30.4 36.4 15.7 16.4 18.6 15.9 9 19.0 20.1 6.9 8.2 25.1 20.1 30.3 35.9 14.9 15.6 18.0 16.7 10 19.9 22.5 7.3 8.4 20.1" 20.6" 33.2 39.0 13.2" 14.4" 16.2 16.8 11 21.2 22.2 6.9 8.8 26.8 20.8 31.7 38.1 15.2 15.1 17.9 16.6 13 20.1 22.1 6.6 8.3 25.0 20.3 30.6 36.4 15.3 17.5 18.2 16.8 Mean" 20.41 21.64 6.82 8.38 25.78 20.12 31.53 37.22 15.70 16.19 17.88! 16.59 Grand meanh 21.0 7.6 23.0 34.4 15.9 17.2 "Rejected as an outlier according to Dixon's test (p = 0.05) (2). hThe mean does not include outliers. 106 BREWING SUGARS AND SYRUPS Vol. 35 RESULTS AND DISCUSSION The data can be better evaluated by considering coefficients of variation for within-laboratory, between-laboratory, and total The data reported by collaborators are given in Tables I, II, and errors. These values are tabulated in Table VI for syrups A and B III. Six collaborators reported data for method 1, GLC of TMS- and Table VII for syrups C and D. It is immediately obvious that oxime derivatives. Some of the data from Collaborator 4 were there was a problem in measuring triose concentration using rejected as outliers, while Collaborator 3 could not obtain triose method 1 (GLC-TMS-Oxime). Comments from collaborators results. Eight collaborators reported data for method 2, GLC of indicated this method was the least preferred because triose peaks TMS derivatives. Three pairs of data were rejected as outliers for were either too small, too broad, or absent. this method. Ten collaborators reported data for method 3, HPLC. Further study of Tables VI and VII shows there may also be a Three pairs of data were also rejected as outliers for this method. problem with triose measurements using method 2 (GLC-TMS), as While the number of outliers appears to be excessive, it should be indicated by the relatively high between-laboratory and total errors noted that, except for one case, only one outlier pair was present in obtained on analysis of the high glucose-low maltose syrups, A and each unit block.