Impacts of oat flour fortification on the rheological, microstructural, digestibility, and sensory characteristics of low-fat, high-protein almond-based gels

Abstract

This research was conducted to investigate the impact of oat flour addition on the physicochemical, microstructural, digestibility, and sensory properties of fermentation-induced low-fat, high-protein almond-based gels. Four distinct levels of oat flour (0 %, 10 %, 20 % and 30 %) were incorporated into low-fat almond-based gel coded as LFA (control), 10A, 20A and 30A. A full-fat almond-based gel (sample coded FFA) was selected as a reference to examine the feasibility of oat flour as a fat replacer in plant-based gels. This investigation encompassed an evaluation of the gels' rheological properties, protein hydrolysis and microstructural changes using an in vitro dynamic rat stomach digestive model called DIVS-II+. The quality assessment demonstrated that incorporating oat flour at levels ranging from 10 % to 30 % increased the hardness and viscosity of the samples while enhancing water-holding capacity and minimising syneresis concerns. Digestion outcomes revealed that fortifying the samples with 20 % oat flour yielded a more densely packed microstructure with higher viscosity and gel strength in the digesta. This formulation exhibited a reduced rate of protein hydrolysis during the initial 150-min digestion phase, with a protein hydrolysis degree comparable to the full digestion time of 180 min. Sensory evaluations indicated that the low-fat sample enriched with 20 % oat flour had higher intensity and preference rating scores in creaminess, thickness, stickiness, and residual coating than the full-fat reference sample made without oat flour. This study underscores oat flour's potential as a nutritional enhancer and effective texture modifier for low-fat, high-protein almond-based gels. Oat flour can elevate these gels' appeal and satiating potential by ameliorating physical properties without compromising sensory attributes.