Hydrocolloids as a tool for modulating the expected satiety of milk-based snacks

Abstract

The objective of this study was to discover which rheological profiles are related to greater expected satiety in semi-solid milk-based snacks. Chocolate flavoured snacks were prepared with four different hydrocolloids (alginate, carrageenan, hydroxypropyl methylcellulose -HPMC- and xanthan gum) at three different concentrations. Rheological measurements were carried out in a controlled stress rheometer using a parallel-plates sensor system. Flow curves were obtained at increasing shear rates (0–200 s−1) and viscoelastic properties were measured using small amplitude oscillatory shear tests. The results showed that, in general, increasing the hydrocolloid concentration resulted in greater yield stress, viscosity, thixotropy and viscoelastic moduli, with differences depending on the type of hydrocolloid. For HPMC and alginate, increasing the concentration mainly increased the viscosity, thixotropy and yield stress, while for xanthan gum and carrageenan the most important changes were rises in elastic modulus values and decreased tan δ. The expected satiety delivered by the different samples was evaluated by 50 participants. The snacks were presented physically, sampled and assessed in relation to picture scales of four “comparison foods”: apple, chocolate bar, sandwich (ham and cheese) and doughnut. The results indicated that the effect on expected satiety of increasing the thickness of the snack differed according to the type of thickener used. Expected satiety increased with higher concentration in the alginate and HPMC samples but not in those prepared with carrageenan or xanthan gum. PLS regression showed that viscosity, not solidity (elasticity), determined the expected satiety of semi-solid milk-based snacks.