Structure-property relationships in groats: Influence on groat breakage.

摘要

Oat damage has negative effects on milling yield and finished product quality. The primary objectives of this thesis were to develop groat structure-property relationships and to identify variables governing groat damage caused by impact dehulling and, in turn, generate a model based on the emergent properties of the groat. The goal of this thesis was to begin to put the bits and pieces of oat science back together in an effort to assist the oat breeder and miller in differentiating genotypes susceptible to groat damage caused by impact dehulling.; We were not aware of any studies assessing the mechanical behavior of groats among genotypes while maintaining constant groat mass and moisture content. Therefore, a parallel flat plate compression test for individual groats was developed, which determined that in addition to groat mass and moisture content, other unknown biological characteristics affect the mechanical behavior of groats.; Interrelationships among specific groat characteristics, mechanical behavior, and damage caused by impact dehulling were developed using regression analysis. We reported that ferulic acid or perhaps diferulate cross-links increase groat stiffness, and syringic acid or perhaps syringate derivatives and moisture decrease groat stiffness (S_max); that β-glucan and protein content increase groat toughness (T); and that moisture content decreases impact damage (as does T/S_max), and starch content increases damage.; We were not aware of any studies assessing the effect of the hull on groat damage. Therefore, we developed a measure of hull damage and examined variation in the outer groat layers using digital image analysis. We determined that the pericarp layer provides groats with protection during impact dehulling (assuming moisture content, starch content, and T/S_max are constant), and that aleurone and hull layers provide little if any protection to groats during impact dehulling.; The challenge for future work in the area of structure-property relationships in groats, and their influence on groat breakage, is to find new variables that provide increased simplicity and generality in the various classes of problems established in this thesis.