PHYSIOCHEMICAL AND FUNCTIONAL PROPERTIES OF SWEET POTATO BREAD AND DIETARY FIBER ENRICHED WHEAT BREAD

Abstract

Recently, food security enhancement through crop diversification and incorporating biomass agricultural products became necessary. This strategy encourages environmental sustainability and economic resilience, which leads to a more stable and circular food system for a secure future. This research focused on food science and nutrition by exploring the applications of natural food systems to enhance the quality and health benefits of food products. Specifically, sweet potato was chosen as the natural food, and (i) physicochemical properties of starches from various sweet potato cultivars were established, (ii) novel functional bread was prepared by fortifying wheat flour with sweet potato puree, and (iii) fortification of wheat bread with dietary fiber (hemicellulose) extracted from corn stove biomass. The focus of study one investigates the structural characterization of starch starches cultivated in Uganda from seven sweet potato varieties (NASPOT8, NASPOT10, NASPOT11, NASPOT12, NASPOT13, Kakamega, Ejumula). These starches were analyzed for structural and physicochemical properties. Results indicated significant differences in amylose content, starch damage, viscosity profiles, and starch digestibility. These variations suggest distinct functional potentials for each cultivar. The second study focused on substituting 50% wheat flour with sweet potato puree (SPP) in bread making, examining the effects on chemical composition, texture, and starch digestibility. The SPP incorporation altered protein, ash, moisture, and bread antioxidant levels, improving texture. The lower glycemic indices, indicating a nutritious xv alternative for enhancing bread with dietary benefits. Finally, the third study involved using hemicellulose from corn stove biomass as a dietary fiber in wheat bread, aiming to improve its nutritional and functional quality. Adding hemicellulose enhanced bread moisture content, antioxidant activity, and resistance starch amount. Hemicellulose addition also led to a softer texture and improved nutritional profiles of bread. The results confirmed the potential of hemicellulose as a functional ingredient. Overall, this thesis demonstrates the potential of utilizing diversified crops like sweet potatoes and agricultural by-products like corn stove biomass for developing healthier, functional food products. The findings also provide valuable insights into the physicochemical properties of these materials and their application in enhancing the nutritional profile of commonly consumed foods like bread, contributing to food innovation and improved health outcomes.