THE DEVELOPMENT OF ALTERNATIVE STRATEGIES FOR USING CHEMICAL OXIDIZING AND REDUCING AGENTS IN FLOURS AS A MEANS OF CONTROLLING GLUTEN STRENGTH PRIOR TO DEVELOPING DOUGH
Date
2020-03-30
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Doctoral
Abstract
The overall goal of this research was to better understand the effects of different commercial enzymes in relation
to commonly used chemical oxidizers on the dough handling and baking performance of wheat flours used in the
baking industry. The use of enzymes is attractive to the baking industry as an alternative to chemical oxidizers as
dough strengtheners as it allows for cleaner labels to be achieved. In this study, a range of commercially grown
Canadian spring wheat (Triticum aestivum L.) cultivars (n = 25) within different wheat market classes were
investigated to understand the inter-relationships between wheat quality, grain and flour composition, and dough
rheology. The cultivars varied in proximate composition which in turn directly impacted their dough handling. MicrodoughLAB absorption was found to be positively correlated with protein content, grain hardness, wet gluten and dry
gluten content, and was found to be negatively correlated with the gluten performance index. Significant correlations
between shear rheology parameters were also found with gluten properties. Protein and gluten properties in particular,
significantly impacted dough strength measurements. Therefore, cultivars displaying stronger gluten strengths may
result in dough with better handling properties. From this set, five cultivars were selected based on their overall
performance and market class representatively to have weak, intermediate, and strong dough strength for probing the
effects of enzymes and chemical oxidizers.
The selected wheat cultivars ranging in gluten strengths from weak (Harvest), intermediate (Lillian, CDC
Plentiful and Stettler) to strong (Glenn) were analyzed in regards to their quality parameters (i.e., proximate
composition, flour yield, gluten properties), dough strength (i.e., empirical and fundamental rheology), and baking
performance with the addition of chemical oxidizers (i.e., ascorbic acid, azodicarbonamide) or commercial enzymes
(i.e., glucose oxidase and fungal xylanase) in different concentrations. Glenn presented better overall quality attributes
compared to the other cultivars, and responded well to additives, especially glucose oxidase, which significantly
improved its dough strength. Glucose oxidase also improved the dough handling of weaker cultivars. The addition of
enzymes gave dough similar rheological properties to dough prepared with chemical oxidizers. In addition, Glenn had
improved baking performance relative to the other cultivars, regardless of the additive and additive concentration.
Whereas Stettler showed poorer baking quality and performance even with the addition of oxidizers and enzymes in
relation to the control.
The effect of a reducing agent (L-cysteine), commonly used in the baking industry was also investigated. The
optimization of the production time vs. quality of bread is crucial for the industry. Therefore, reducing agents can be
used in stronger wheat cultivars as means to improve efficiency of production (i.e., lower mixing time) and result in
equal or higher quality bread loaf (i.e., loaf volume). The addition of L-cys resulted in significant decreases in dough
strength, however stronger gluten strength wheats were less effected by its addition. The stronger wheats had improved
dough handling properties, loaf volume, and softer crumb structure. The addition of L-cys also reduced mixing time
up to 47%, increased loaf volume (up to 9%), and elasticity of the products, those characteristics are desired to increase
the efficiency of the automated processes for bread products.
Description
Keywords
Clean label, Enzymes, Baking, Chemical oxidizers
Citation
Degree
Doctor of Philosophy (Ph.D.)
Department
Food and Bioproduct Sciences
Program
Food Science