Multilevel characterization and in vitro digestion of starch-based food systems enriched with dietary fıber

Güven, Özge
Non starch constituents may influence the structural, nutri functional, and techno functional properties of wheat starch within food systems. Among these constituents, dietary fibers (DFs) represent a group possessing various health benefits, such as reducing the risk of heart disease, diabetes, and certain types of cancer. Moreover, DFs have been associated with favorable effects on the digestive system and potentially lower glycemic index. Given these promising benefits, there is a growing interest in developing products with high fiber content, particularly within the bakery product industry. The effect of DFs depends on the DF type (soluble/insoluble) and the processing technology used. Also, additional ingredients such as lipids and proteins may affect the mechanism of cooking-associated structural changes in the presence of DFs. Building upon these highlights, the objective of this thesis was twofold: first, to examine the structural and digestive characteristics of wheat starch in both the presence and absence of soluble and insoluble DFs, inulin, and cellulose through the model systems. Subsequently, to expand the investigation to a product-based study by examining the structural, quality, and starch digestion properties of psyllium-enriched bread with and without a commercial emulsifier. Within this context, a broad scope of techniques was used to examine structural changes of starch, from macro to micro scale. The rapidly digestible, slowly digestible, and undigestible starch fractions were determined by in vitro digestion analysis. Also, for the bread system study, quality properties were analyzed, and a sensory panel was conducted to predict the acceptance of products by the consumers. According to the model system study and product-based system study results, specific structural properties were affected upon processing in the presence of soluble DFs, inulin, and psyllium. Insoluble DF cellulose did not lead to a change in structure. The psyllium-enriched bread with and without monoglyceride was acceptable in terms of quality and sensory properties. In addition, DF addition lowered the rapidly digestible starch content by diluting the amount of starch in the system.
Citation Formats
Ö. Güven, “Multilevel characterization and in vitro digestion of starch-based food systems enriched with dietary fıber,” Ph.D. - Doctoral Program, Middle East Technical University, 2023.