Location: Grain Quality and Structure Research
Project Number: 3020-44000-027-015-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Sep 1, 2024
End Date: Aug 31, 2027
Objective:
Wheat is among the most cultivated cereal crops worldwide. The milling of wheat yields wheat bran as the major byproduct, which is separated from the endosperm by roller milling. Total annual production of wheat bran is around 150 million tons, the majority of which is used in animal feeds. Adding wheat bran directly into bakery formulation disrupts gluten development, adversely affecting dough rheology and the quality and sensory of the finished products. Nonetheless, wheat bran has a remarkable nutritional profile. It is rich in dietary fiber at approximately 50% of its weight in the form of cellulose, lignan, and xylan constituents. It also contains significant protein levels around 15%, featuring a more balanced amino acid composition than white flour, along with various vitamins, minerals, and bioactive phytochemicals. Historically regarded as a low-value byproduct, wheat bran holds promise as a versatile source for deriving various value-added food ingredients. These ingredients are particularly promising for bakery applications, further enhancing economic returns in cereal processing. Our preliminary research demonstrated that incorporating up to 7.5% of wheat bran aqueous extracts into wheat flour significantly improved its dough rheological properties and bread-making performances. The objectives of this project are to extract functional fractions such as soluble extracts, proteins and peptides, and fibers from wheat brans, characterize their physicochemical and functional properties, and evaluate their applicability in bread products.
Approach:
Six hard winter wheat varieties with protein content ranging from 10-15% will be used to produce white flour and wheat bran (including the germ) using a roller mill. Each bran sample will be further processed in a hammer mill to reduce the average particle size to below 200 um. Initially, bran will be extracted with deionized water to obtain soluble extracts. The residues will be sequentially extracted to isolate proteins and peptides using alkaline solutions and enzymes, as well as soluble and insoluble fibers following AOAC methods. All the extracts will be lyophilized and thoroughly characterized, including analyses of proximate composition, monosaccharide composition, amino acid composition, and various advanced methods such as chromatography, spectroscopy, and microscopy will also be used. The extracts will be incorporated into white flour to evaluate their effects on dough mixing properties and bread quality. Correlations among various parameters will be established through principal component analysis.
