Influence of Extrusion Mixing on Preparing Lipid Complexed Pea Starch for Functional Foods

The present work examines the ability to reactively modify pea starch by lipid complexing in a twin‐screw extruder in order to produce a functional food product. The study considers the influence of moisture content, lipid type (myristic acid, palmitic acid) and content, in tests with differing screw designs to reduce enzymatic digestion. The modified starch was characterized for its physicochemical properties (bound lipid content, pasting properties, and Englyst digestion profiles). With near complete conversion at all tested lipid concentrations, differences found in enzyme resistance and pasting properties for the extruded samples were attributed to differences in the mixing environment. The lipid complexed pea starches under optimized conditions achieved a significant but moderate increase in either resistant starch (from 7.8% to 20%) or slowly digestible starch (from 12% to 23%) content compared to their native counterparts; however, the sought nutritional fractions (slowly digestible and resistant) could only be improved simultaneously with palmitic acid. The highest resistant fraction produced in the study corresponded to the higher shear environment tested and for complexes prepared at the highest lipid content.