Performing Department
(N/A)
Non Technical Summary
Starches are everywhere in our daily lives - e.g., foods, pharmaceuticals, biomaterials, and consumer products. Despite their common use, industries employ trial-and-error approaches to tune the material properties of starch pastes in applications like food, paper coating, tableting, and high moisture extrusion. To overcome this roadblock, one needs to create predictive, physics-based models to quantitatively describe the swelling and rupture of starch granules as they are heated in water, since these processes play a major role in the material properties of the starch dispersion.This project develops first-principles models to describe the swelling and rupture of starch granules in solution, given their physical properties. Our prior results indicate that a physics-based approach can forecast the swelling of starch granules from traditional sources (e.g., maize, rice) under a wide range of chemistries and heating conditions, and furthermore can predict the paste's mechanical properties (elasticity). The first part of the project will apply similar ideas to non-traditional starches from pulses and ancient grains, as data is lacking in industry and such starches are becoming increasingly important in their product portfolios. The second part of the project extends the theory to quantify how additives like sugars and sugar substitutes alter the swelling kinetics of the starches. The last part of the project combines microscopy experiments with modeling to visualize granule rupture and identify its failure criterion. An open-source software will be created to forecast the size distribution and flow behavior of these starches during swelling and rupture under arbitrary heating, given their tabulated physical properties. This work will be performed with close collaboration with industry, with information disseminated through workshops and webinars. The project will also help train PhD students at Purdue and University of British Columbia, as well as train under-represented students in a newly developed doctoral program in the College of Agriculture and Environmental Sciences at North Carolina A&T, a historically Black college or university (HBCU).
Animal Health Component
25%
Research Effort Categories
Basic
65%
Applied
25%
Developmental
10%
Goals / Objectives
The goals of this project are to:Predict flow behavior of non-traditional starch dispersions during swelling. We will examine the heating of starch granules from pulses (red bean, black bean, chickpea, pea) and ancient grains (barley, millet, buckwheat) in high-moisture dispersions, and track the dispersion's particle size distribution and linear elasticity over time. We will also track the swelling of individual starch granules via a unique microscopy platform (particle cohort study or ParCS). Size distribution data will be compared against a kinetic model that combines ideas from Flory polymer swelling theories and diffusion of water into the starch granule. Rheological data will be compared against a rheology theory for pastes in the limit of large granule volume fraction.Predict how sugar and sugar substitutes alter starch swelling. We will modify the Flory swelling models to consider the thermodynamic interactions between starch, water, and short chain carbohydrates (sugars and sugar substitutes). The effects of the carbohydrate additives on the partitioning within the starch granules as well as reduction in water activity will be accounted for in the modified models to forecast the extent of granule swelling. Results from simulations will be compared to both size distribution measurements and microscopy measurements of granule swelling with sugars/sugar substitutes, subject to different heating profiles.Incorporate starch granule rupture into swelling models. We will combine time-lapse microscopy experiments using the ParCS apparatus with continuum mechanics modeling to characterize the different modes of granule rupture during heating, and relate the failure criterion to the granule physical properties. We will then develop a simulation to incorporate the simultaneous effects of swelling and rupture to predict the size distribution of a dispersion over time under arbitrary heating conditions.Material properties of pulses and ancient grains obtained from the above studies will be placed in a database (provided the starches are not proprietary). A computer program will be developed to predict size distribution and rheology of the starches.
Project Methods
Experimental methods:Starch extraction: We will extract starches from pulses (red bean, black bean, pea, and chickpea) and ancient grains (millet, buckwheat, barley), some of which will be provided by our industrial collaborator Archer Daniels Midland. Details are given in several publications.Starch pasting: After extracting starches, we will form pastes of a given starch/ingredient combination by heating an aqueous suspension of starch (0.1-8.0 wt.%) and ingredient at a given temperature (60oC