Investigation into the use of pyrolysis-elemental analysis for the measurement of carbohydrates in foodstuffs

The development of a method for the determination of carbohydrate based upon pyrolysis-elemental analysis (Py-EA) is described. The method uses a more “direct” approach to determine carbohydrate compared to traditional “by difference” techniques such as the Weende system. The carbohydrate content of foods is quantified by comparison of the carbon monoxide (CO) released by pyrolysis with that released by a known mass of sucrose. “Carbohydrate” response from other food components (fat, protein and fibre), normalised against sucrose were 0.2, 0.47 and 0.9, respectively. Although differences were observed between the new procedure and data obtained using the Weende procedure, they were within range when including measurement uncertainty. The new procedure gave similar values to the Weende procedure when analysing 65 foods ranging from trace to high content carbohydrate foods. The results demonstrated the broad applicability of the procedure and its ability to get similar results.Repeatability obtained using the new techniqe ranged from R.S.D. 1 to 13%. Improvements in the precision of the procedure could be made through replicate analysis, improvements in instrumentation and the use of targeted reference materials for specific matrices that are to be analysed.