Evaluation of the prebiotic galacto-oligosaccharides addition in the traditional Portuguese cake bolo-de-arroz

Abstract

The global epidemic of overweight and obesity have become a major public health problem in several parts of the world. The increasing prevalence of those medical conditions is associated with many diet-related chronic diseases (diabetes mellitus, cardiovascular disease, etc.). The consumers prefer low-sugar and functional food products. In this context, prebiotics compounds have attracted global attention as functional food ingredients due to their beneficial effects over several physiological functions, namely on the gastrointestinal tract [1]. Prebiotic Galacto-oligosaccharides (GOS) are recognized as safe food ingredients and are used in the EU from two decades [2]. In this study, traditional Portuguese cakes bolo-de-arroz were produced containing (a) 100% of sugar (100), (b) 75% of sugar supplemented with 0,9% GOS (75GOS), and compared with commercial bolo-de-arroz (commercial). Physical features (apparent density and porosity), optical properties (colour) and textural characterization (texture profile analysis) were measured after 1 day of baking and during 5 days of storage. Water adsorption isotherms at 20ºC were determined by gravimetric method using saturated salt solutions. Table shows some results of tested samples after 1 day of baking. No significant differences were found between 75GOS and commercial samples and 100 sample show higher porosity values and lowest apparent density. Color parameters were invariant for the GOS addition. Textural results indicate that low sugar content promotes the interactions between proteins and starch and hardness, gumminess and chewiness increased. On the other hand, water adsorption isotherms can be classified as type II and they were satisfactorily modelled by means of Oswin model.