Chicory Inulin as a Functional Fat Replacer in Wheat Tortillas: Rheological, Nutritional, Textural, and Molecular Insights

Inulin is emerging as a promising fat replacer in food products, though reducing fat content can alter molecular interactions and impact product quality. This study examines the effects of partial (33% and 66%) and total (100%) replacement of vegetable shortening with chicory inulin on the rheological, nutritional, textural, and molecular characteristics of wheat tortillas. Mixolab results demonstrated that substituting fat with inulin altered the initial consistency and thermomechanical properties of the tortilla doughs, increasing the mixing stability, as well as the hot peak and final consistencies. Inulin incorporation increased the total dietary fiber from 4.8 g/100 g to a range of 5.7 to 7.5 g/100 g, primarily enhancing the soluble fiber fraction, which rose from 2.7 g/100 g to 5.3 g/100 g. Fat replacement significantly lowered the fat calories/total calories ratio from 26% to as low as 2%. Tortillas with inulin exhibited greater extensibility, and 33% and 66% fat replacement produced softer tortillas. FTIR analysis revealed a reduction in ordered and rigid retrograded starch structures due to inulin incorporation, along with intensified interactions through hydrogen bonding. Differential scanning calorimetry identified amylose-lipid complex formation, particularly in tortillas with 33% and 66% fat replacement, suggesting that these structures are favored by the presence of inulin. These findings indicate that inulin enhances the nutritional profile of tortillas and promotes beneficial molecular interactions with water, starch, and fat. Consequently, including inulin as fat replacer improves the quality attributes of reduced-fat wheat tortillas PRACTICAL APPLICATIONS: This research demonstrated that inulin could serve as an effective fat replacer for producing tortillas with an enhanced nutritional profile in terms of fat reduction and fiber increase, while maintaining adequate texture characteristics (softness and flexibility). These findings are significant for commercial wheat tortilla manufacturing, where formulation strategies that reduce fat while maintaining processing performance are desirable. The incorporation of chicory inulin could be integrated into existing industrial processes, suggesting good potential for process scalability without major equipment modifications. Although using inulin may increase formulation costs compared to vegetable shortening, the growing demand for low-fat and high-fiber wheat-based products offers significant commercial potential.