Differential saliva-induced breakdown of starch filled protein gels in relation to sensory perception

In this study, the differential breakdown of protein gels containing four types of high and low cross-linked starch granules were studied. Susceptibility to saliva-induced breakdown of starch granules and the consequences of these for overall breakdown of the gel matrix were captured using a multiple extrusion cell (MEC). Gels filled with two types of starch were used for sensorial evaluation by a QDA panel and the mechanical impact of the starch granules on these latter gels was characterized using uniaxial compression measurements. These data were used to better understand differences in sensory mouth feel attributes.MEC measurements indicated that the low cross-linked starches were more susceptible to saliva-induced breakdown compared to their highly cross-linked counterparts. The sensory space of starch filled gels was divided into three dimensions. Protein content of the gel matrix determined one dimension, resulting in high sensory ratings for separating and slippery mouth feel. The distinction into the two other dimensions, one being dominated by grainy/spreadable/sticky and the other by crumbly/crumbly effort, originates mainly from different starch types used: larger starch granules from the low cross-linked potato starch were perceived as more grainy and gels filled with these granules were more spreadable with a lower rating for crumbly and crumbly effort. Surprisingly, in most cases ratings for firm for both starch types were more or less comparable, indicating that these granules behave as inert fillers in a rather similar way, as also suggested by compression measurements. This work indicates that low cross-linked potato starch displays a higher susceptibility for digestion by amylase present in saliva. This is possibly the reason for the larger spreadability and lower rating for crumbly effort of the gel containing this type of starch.