Document Type

Thesis - Open Access

Award Date

2020

Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Padmanaban Krishnan

Keywords

baking quality, dough expansion, dough rheology, flour quality, loaf volume, wheat quality

Abstract

Bread loaf volume is a significant economic factor in the baking industry. Numerous flour and dough quality tests exist in estimating the functional traits of wheat. However, none of these tests accurately or fully predict bread loaf volume. The ultimate reliable method to determine the baking potential of wheat flours is a standard baking experiment which is time-consuming and effort-intensive. Therefore, there is a need to develop empirical methods to predict the baking potential of wheat flours that use small sample sizes and yet, are economical to implement in large throughput wheat breeding programs. A Vacuum Dough Expansion System (VDES) was fabricated to expand optimally developed dough prepared from flour and water. Dough expansion was carried out in a chamber and the maximum height of the expanding dough was recorded. The VDES was evaluated for its ability to consistently expand dough and its applicability in predicting bread loaf volume. The study also investigated a simple and rapid chemical test. One such test is the hybrid SDS-SRC sedimentation designed for evaluating winter wheat quality. This test was evaluated for applicability to hard red spring (HRS) wheat as well. The hybrid SDS- SRC test measures gluten proteins that precipitate on the addition of solvents and detergents. Conventional flour tests, dough quality tests and baking experiments were also done in parallel to determine relationships between various tests. Preliminary investigation to study the applicability of the VDES was performed on a low-protein pastry flour (7.3 % gluten content) which was further enriched with vital gluten (7.3 to 14.7% vital gluten). Dough expansion height was statistically significantly correlated with corresponding bread loaf volume (r = 0.96). Additionally, dough expansion height was statistically significantly correlated to gluten content in the blends (r = 0.97). Two validation studies were then conducted employing a total of 147 samples from two economic classes of wheat namely hard red spring (HRS) and hard red winter (HRW). In the investigation on 24 HRW wheat cultivars, specific loaf volume (SLV; Loaf volume/weight) was statistically significantly correlated to dough expansion height (r = 0.47) and weight value (obtained from the hybrid SDS-SRC sedimentation test, r = 0.54). The best predictor of SLV in this sample set was flour protein content (r = 0.62). In another investigation comprising 33 HRS wheat cultivars grown at three growing locations, loaf volume was found to be significantly correlated with dough expansion height (r = 0.38). However, in individual growing locations, predictability of bread loaf volume from dough expansion height was not seen. Statistically significant correlation was also found between weight value and bread loaf volume in all the three growing locations of HRS wheat samples. The correlation coefficient (r) between weight value and bread loaf volume was 0.50 in Brookings growing location, 0.59 in Groton growing location, and 0.41 in Selby growing location. The research established a proof of concept for dough expansion and its potential applicability in measuring the baking quality of wheat. The VDES provided a linkage between true baking tests and other chemical indicators of wheat and dough quality. The effect of vital wheat gluten addition on dough expansion height as evaluated by the VDES was linear and incremental. The hybrid SDS-SRC sedimentation test was effective and consistent in predicting the loaf volume of HRW as well as HRS wheat cultivars. The test was also effective in predicting loaf volume in the environment affected by drought and cultivars with high protein.

Library of Congress Subject Headings

Bread -- Quality.
Wheat -- Varieties -- Analysis.
Wheat -- Analysis.
Winter wheat -- Analysis.

Format

application/pdf

Number of Pages

129

Publisher

South Dakota State University

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Included in

Food Science Commons

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Rights Statement

In Copyright