CHARACTERIZATION OF RADIOFREQUENCY-TREATED WHEAT FLOUR: PROXIMATE COMPOSITION AND PASTING PROPERTIES

Radiofrequency (RF) is an emerging dielectric heating technology with potential for application in the decontamination of low-moisture ingredients, such as flours. Unlike microwaves, RF provides greater uniformity of the electric field and deeper penetration, resulting in more homogeneous heating. Despite its established use in microbiological safety, little is known about the effects of RF on the functional and nutritional properties of foods. In this context, this study aimed to characterize a wheat flour treated with RF, in order to evaluate possible changes in its physicochemical properties, pasting behavior, gluten content and index, and Falling Number. The treatment was carried out for 20 minutes using a power of 60 kW, with a final temperature of 52.5 °C. Analyses of moisture (AACC 44-15.02), ash (AACC 08-01.01), proteins (AACC 46-13.01, adapted by Barbano and Clark), lipids (AACC 30-25.01), and carbohydrates (by difference) were performed on the treated flour. Analyses of gluten content and index were carried out using the Glutomatic (AACC 38-12.02) and Falling Number (AACC 56-81.03), while pasting properties were assessed with the Rapid Visco Analyser (RVA) (AACC 76-21.01), comparing the treated flour with a commercial untreated flour. The results indicated that the proximate composition of the treated flour remained within the requirements of the legislation. The gluten index showed a high value (91.20 ± 5.06), suggesting good technological quality of the protein for baking after treatment. The Falling Number value (429 ± 26 s) was high, indicating low enzymatic activity. In the RVA analysis, the treated flour presented a slight reduction in peak, trough, and final viscosities compared with the commercial flour, and a small increase in retrogradation tendency, indicating that RF did not significantly alter pasting properties. It is concluded that RF thermal treatment, under the evaluated conditions, did not promote relevant changes in the studied characteristics of wheat flour. These results reinforce the potential of RF as a viable alternative to thermal processing of dry ingredients, without impairing technological functionality. Considering the hypothesis that RF may even improve the application properties of flour in bakery products, future studies will address more intense treatments and the repetition of the analyses carried out here.