Abstract

The objective of this work was to study the effect of fructose and glucose content on the rheological behavior of syrups. Initially, high fructose syrup from the fructans present in leaves, bases and head of Agave tequilana Weber blue was obtained. Then, its contents of moisture, ash, fructose, glucose and direct and total reducing sugars were determined. Finally, the physicochemical properties of the syrups were evaluated and compared with a high commercial fructose corn syrup (Frudex 55) and other fructose, glucose and sucrose syrups. All of them had the same temperature and concentration of total solids. All syrups behaved as Newtonian fluids and had no statistically significant differences (p <0.05) in their density, water activity and in direct and total reducing sugars. The viscosity and surface tension of syrup depended on its fructose and glucose content. Also, greater fructose content produces syrups with lower viscosity and lower surface tension.

Key words: High fructose syrups, viscosity, rheological behavior, Newtonian fluids.

Abbreviation

HPLC, High pressure liquid chromatographic; ADP, average degree of polymerization; HFS, high fructose syrup; HFCS, high fructose corn syrup. TRS,total reducing sugars; DRS, direct reducing sugars; G, glucose; F, fructose; DB, dry basis; a_w, water activity; h, viscosity; t, shear stress; g, shear rate; ºBrix, soluble solids %; K, consistency index; n, flow behavior index.