Enhancement of the pasting properties of teff and maize starches through wet-heat processing with added stearic acid

Abstract

This study determined the effects of stearic acid on the functional properties of teff 27 starch, a compound granule starch in comparison to maize, a simple type granule starch. 28 Stearic acid was incorporated into teff and maize starches and pasted (held for 5 or 120 29 min at 91°C) with an RVA (Rapid Visco Analyser). Teff starch with added stearic acid 30 (0.25 and 1.5% starch basis) did not produce a pasting peak viscosity within short 31 holding time (5 min) compared to maize starch. The paste viscosity of both teff and 32 maize starches with stearic acid increased to about three times with long pasting (120 33 min). This increase in paste viscosity occurred earlier for teff starch than maize starch. 34 Teff starch with stearic acid was more viscous and was non-gelling. Confocal laser 35 scanning microscopy showed that stearic acid did not diffuse in teff starch granules, but 36 seemed to coat them. However, stearic acid diffused inside maize starch granule through 37 channels. This microstructural difference may explain the different pasting behavior. 38 The early high paste viscosity and non gelling properties of the teff starch modified with 39 stearic acid could have promising applications in foods for example better mouthfeel 40 with lower starch concentration.