Stable isotope (δ13C) profiling of xylitol and sugar in South Africa
Date
2017-05
Authors
Symes, C.
Loubser, E.
Woodborne, S.
Journal Title
Journal ISSN
Volume Title
Publisher
Academy of Science of South Africa (ASSAf)
Abstract
Xylitol is an alternative sweetener to sucrose, glucose and fructose, and is available under a number
of brands in South Africa. Carbon stable isotope values (δ13C) of a selection of commercially available
xylitol products (n=28) were analysed and compared with sugar samples (n=29). Sugarcane (C4) and
beet sugar (C3) derived sugar samples aligned with published values of source, although two samples
that indicated a sugarcane origin suggested a beet sugar origin. Control corn-derived samples defined
a stepwise xylose to xylitol discrimination of +0.7‰. The distinction between C3- and C4-derived xylitol
was less clear with three samples difficult to define (range = -14.8 to -17.1‰). The values for a suite
of xylitol samples (-22.3‰ to -19.7‰; n=8) that aligned closely with a suspected C3-derived xylose,
were ~8‰ more positive than known birch isotope values. Some xylitol samples may thus represent
(1) a mixture of C3- and C4-derived products, (2) derivation from a CAM species source or (3) different
processing techniques in which the discrimination values of xylose from corn, and xylose from birch,
may differ because of the respective chemical processing techniques. No samples that claimed a birch
bark origin were within the range of samples suggested to be corn derived (i.e. -13.0‰ to -9.7‰,
n=16). We suggest that the threshold values provided are relatively robust for defining the origins of
xylitol and sugar, and can be used in determining the authenticity and claims of suppliers and producers.
Description
Keywords
sucrose, disaccharide, maize, sugarcane, sugar beet, birch
Citation
Symes, C, Loubser, E. and Woodborne, S. 2017. Stable isotope (δ13C) profiling of xylitol and sugar in South Africa. SOUTH AFRICAN JOURNAL OF SCIENCE 113(5-6), Article number 20160276.