E. Arena et al., Thermal damage in blood orange juice: kinetics of 5-hydroxymethyl-2-furancarboxaldehyde formation, INT J FOOD, 36(2), 2001, pp. 145-151
Citations number
34
Categorie Soggetti
Food Science/Nutrition
Journal title
INTERNATIONAL JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Formation of 5-hydroxymethyl-2-furancarboxaldehyde (HMF) was studied kineti
cally by HPLC in blood orange juice and model systems of fructose, glucose
and sucrose at different acidic pH values and temperatures. The ultraviolet
absorption of the solutions changes during reaction by forming an enediol
intermediate, which slowly converts into HMF Pseudo first order rate coeffi
cients were used for comparing reactivity of sugars in model systems and in
fortified juices. Glucose degrades much more slowly than fructose, while t
he reactivity of sucrose depends on pH value and temperature. The activatio
n energy for sucrose was about 20 kcal mol(-1) higher than fructose, and su
ch a difference can be ascribed to the rate-determining contribution of the
preliminary hydrolysis step. First order rate coefficients in orange juice
s were similar to those of model systems at comparable pH and temperature,
indicating that sugar degradation occurs without any interference of other
components, thus excluding the presence of the Maillard's reaction. HMF con
tent constitutes an index of juice deterioration, therefore it should be in
cluded among the parameters of quality for commercial blood orange juices.