Effect of microwave dry-heat treatment of wheat flour in the in vitro digestibility of bread starch

• Published in: International journal of biological macromolecules Vol. 315; no. Pt 1; p. 144392
• Main Authors: Morales-Huerta, Alfonso, Vernon-Carter, E. Jaime, Alvarez-Ramirez, Jose, Román-Guerrero, Angélica
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2025
• Subjects: Bread - analysis; breads; crystal structure; Digestibility; digestible carbohydrates; Digestion; Flour - analysis; heat; Hot Temperature; household equipment; Microwave; microwave treatment; Microwaves; Molecular organization; multivariate analysis; resistant starch; Spectroscopy, Fourier Transform Infrared; Starch - chemistry; Triticum - chemistry; Water - chemistry; Wheat flour; X-Ray Diffraction; Microwave; Wheat flour; Molecular organization; Digestibility
• ISSN: 0141-8130; 1879-0003; 1879-0003
• DOI: 10.1016/j.ijbiomac.2025.144392

Commercial wheat flour (13 g moisture.100 g−1) was subjected to dry heat microwave treatment (3.2 W.g−1) using household equipment. The treatment time (15, 30, 60 and 120 s) was considered as the control variable for evaluating the effect on the structural properties of the flour components (water, proteins and starch), based on XRD and FTIR analyses. The relatively short treatment times had a significant impact on most of the structural properties, with only the relative crystallinity of the starch remaining almost intact (19.94–20.87 %). The structure of water changed from being predominantly low density to being predominantly high density. The secondary structure of the proteins shifted to higher contents of α-helix structures (0.00 to 21.59 %) at the expense of the content of β-sheet structures. The short-range order of starch increased (0.21 to 0.26 FTIR index) with treatment time. The bread prepared with the treated flour increased about 50 % the content of resistant starch (24.47 to 46.16 %) accompanied by a reduction of rapidly digestible starch (36.29 to 14.93 %). A multivariate analysis showed that the water structure in the treated flour played an important role in modifying the molecular organization of wheat flour, and the digestibility of starch in bread.