Resíduo do processo de laminação de milho, modificações físicas e aplicação em pão de arepa

Abstract

The aim of this study was to evaluate the feasibility of using the "fines" residue from corn flakes processing as a novel ingredient for arepa bread, targeting export markets. Three physical modification methods were tested: extrusion, oven drying, and autoclaving. 1) In a thermoplastic extruder with 16% moisture content and temperatures of 40 °C, 60 °C, and 85 °C in the 1st, 2nd, and 3rd heating zones, respectively; 2) In an oven with air circulation, 30% moisture content, and an initial temperature of 100 °C for 6 hours, followed by 50 °C for 15 hours; and 3) In an autoclave with direct steam applied to the residue at 30% moisture content and a temperature of 120 °C for 1 hour. The granulometry evaluation results showed that the extruded fines flour (FFEx) had a mean geometric diameter (DGM) of 556.89, classifying it as medium flour. In terms of color, FFEx exhibited the lowest L* value (85.92), indicating darker color, and high b* (32.59) and C* (32.76) values, making it ideal for the production of yellow foods. Regarding technological properties, it stood out with the highest water absorption index (WAI = 13.49) and solubility index (WSI = 58.96), indicating its potential for use in gluten-free bakery products such as arepa bread. Thermal properties revealed that FFEx had a high transition temperature (Tpico = 116.50 °C) and low enthalpy (ΔH = 1.12), suggesting higher starch gelatinization. Extrusion resulted in complete starch gelatinization, with cold viscosity (VI = 319.67 cP), which is also favorable for gluten-free bakery products. Therefore, FFEx was chosen to be used at different partial substitution levels in arepa bread formulations. The arepa bread formulation with the best sensory acceptance combined 70% raw residue and 30% FFEx, achieving an acceptability index of 77%, meeting the microbiological standards required by Brazilian legislation and importing countries. In terms of organoleptic properties, the selected arepa bread showed similar evaluations for all attributes compared to commercial arepa bread and the best result for purchase intent. Compared to commercial arepa breads, the selected arepa bread exhibited 30 to 60% higher lipid content and approximately 24% more protein, which contributes to a more balanced nutritional profile in terms of macronutrients. It was concluded that the use of this by-product in arepa bread production is feasible and could enhance the sustainability and added value of the by-product, making it suitable for commercialization as a commercial blend.