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
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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.
DegreeDoctor of Philosophy (Ph.D.)
DepartmentFood and Bioproduct Sciences
CommitteeKorber, Darren; Hucl, Pierre; Tyler, Robert; Tanaka, Takuji
Copyright DateMarch 2020
Clean label, Enzymes, Baking, Chemical oxidizers