Methodology to predict the time-dependent storage modulus of starch suspensions during heating

Abstract We present a methodology to predict the storage modulus ( G ’ ) of starch paste due to granule swelling, given the physical properties of the starch granule and temperature history. This was tested on experimental measurements of granule size distribution and G ’ for 8% w/w suspensions of waxy maize, normal maize, waxy rice, normal rice, and cross linked normal maize – all heated to different temperatures (65-90 ⁰C) with holding times between 2-60 min. Experimental data of storage modulus G ′ vs volume fraction ϕ fall onto a master curve when G ′ is normalized by a multiple of γ / R ¯ , where γ is the granule-solvent interfacial energy, and R ¯ is the average granule size. We show that one can combine this master curve with starch swelling theories to forecast the time-dependent rheology of starches. This work also demonstrates that granule-solvent interfacial energy is a key physical parameter in controlling starch rheology.