Call number: LD2668 .T4 1946 H4 / Master of Science

The purpose of this research was to examine the relationship of the protein and lipid content of soft wheat flour to baking quality and their changes as a result of chlorination. Coker 916, soft red winter wheat, was grown under different fertilization treatments involving rate and application time to alter protein content. One-half of all flour treatments were subjected to chlorination. The lipid and protein content, gliadin and glutenin composition, microstructure, rheological properties, ash, pH and color were examined. Baked angel food cakes were evaluated by volume, tenderness, color, cohesiveness, crumb structure and microstructure (SEM). Gelatinization temperatures of batters were measured by Differential Scanning Calorimetry (DSC). Sensory analysis was judged by quantitative descriptive analysis (QDA). Increased levels of fertilization of the grain increased the protein content (8-11%) of the flour. Cakes from flours of Increased protein content were significantly lower in volume than cakes of flours of lower protein content. Chlorination decreased protein content in flour which affected the glutenin composition in some flours. Gliadin content remained unchanged. Doughs of chlorinated flours were significantly less stable as measured by mixing time stability and mixing time index. Chlorination decreased the unsaturated fatty acid methyl esters (FAME). There was strong correlation between evenness of cell structure and the decrease of fatty acids 18:1, 18:2, and 18:3 with chlorination. Phospholipids which were qualitatively evaluated were implicated with cell evenness. Cakes of chlorinated flours were significantly less in volume and tenderness, but the structure showed complete starch gelatinization, increased whiteness and cell evenness. Sensory data correlated significantly with objective data. Chlorination of flour stabilized the structure of the baked product. Low protein and decreased FAME content improved the baking properties of the flour. Flours of lower protein and a lower lipid content that are chlorinated are recommended for baked products such as cakes and biscuits. / Ph. D.

The effects of variation in nitrogen application during two growing seasons to Coker 916, a soft red winter wheat, on wheat grain and flour protein content and bread baking properties were examined. Nitrogen fertilization regimens tested included the single spring application of 168 kg/ha in growth stages 25 or 30, the split spring application of 224 kg/ha in growth stages 25 and 30, and no nitrogen application either in growth stages 25 and 30. Variation in rate of nitrogen application had a more consistent effect on grain and flour protein than did variation in timing. Grain and flour protein content increased with increased nitrogen fertilization. The gliadin to glutenin protein ratio of the flour was reduced as the rate of grain nitrogen application increased. Significant differences were found in the flour gliadin percent protein with variation in spring nitrogen management. Fractionation and resolution of gliadin and glutenin components using SDS-PAGE revealed changes in the relative quantities present of two high molecular weight glutenin subunits (108,000 and 91,000 daltons), one low molecular weight glutenin subunit (40,500 daltons) and the <i>ω</i>-gliadin (44,000 daltons) fraction of experimental flours. Differences in dough rheological properties and baking characteristics of the flour were associated with variation in nitrogen management. Increased nitrogen fertilization resulted in a stronger, more extensible dough with improved mixing tolerance and dough handling characteristics. Increased flour protein was associated with larger bread loaf volume and darker crust color. Sensory panelists found significant differences in the bread crust color, texture and taste, bread aroma, crumb texture and chewiness. This experiment demonstrated that a change in nitrogen management of Coker 916 wheat resulted in a distinct change in protein composition and bread baking properties of experimentally milled flour. / Ph. D.

Call number: LD2668 .T4 1985 D73 / Master of Science