Stability of Oligosaccharides Derived from Lactose and Lactulose regarding Rheological and Thermal Properties

الملخص EN

Prebiotic carbohydrates derived from lactulose (OsLu) are appealing ingredients that provide beneficial effects following their fermentation by the gut microbiota; however, more investigation is needed to evaluate their technological properties and applicability as a functional food ingredient in the market.

In this paper, a comparative study on the rheological and thermal behavior of OsLu and a commercial mixture of galactooligosaccharides (GOS) was carried out.

In both cases, there was a strong influence of temperature and shear rate on viscosity.

Viscosity of OsLu was higher than that of commercial GOS and variations and rheopexy cycles were also higher for OsLu.

The exponential increase of viscosity associated with the structural changes took place later in OsLu than in commercial GOS, suggesting more stability to the shear over time in the former.

More stability of OsLu was also observed in the study of the effect of temperature on viscosity.

In addition, the thermal study indicated different behavior of both prebiotics under the assayed conditions, showing that OsLu have lower values of glass transition temperature (Tg) than commercial GOS and that commercial GOS are more sensible against humidity.

The results here obtained provide important information on the treatment and storage conditions of these prebiotic ingredients during the elaboration of functional foods.