The Corn Stalks as a Novel Source of Functional Dietary Fiber: Process Optimization and Product Characterization

Abstract

The growing demand for dietary fiber (DF) has encouraged the exploration of sustainable and low-cost sources from agricultural by-products. Corn stalks are an abundant agricultural residue that remains underutilized as a potential source of dietary fiber. This study aimed to optimize the alkali extraction of DF from corn stalks (Zea mays, L.) using Response Surface Methodology (RSM) with a Central Composite Design (CCD). Three independent variables, namely temperature (70-90°C), time (50-70 min), and NaOH concentration (15-25%), were investigated for their effects on DF yield. The model showed a high significance (p<0.0001) with R² = 0.99, indicating excellent predictive accuracy. The optimal extraction conditions were 82.29°C, 62.06 min, and 23.03% NaOH, resulting in a maximum DF yield of 25.75%. Verification experiments confirmed the model’s reliability, with an experimental yield of 25.43 ± 0.24%. The extracted DF exhibited favorable functional properties, including high water holding capacity/WHC (4.7 ± 0.08 g/g), water binding capacity/WBC (2.7 ± 0.05 g/g), swelling capacity/SW (5.12 mL/g), oil holding capacity/OHC (1.8 ± 0.07 g/g), and Fourier Transform Infrared Spectroscopy (FTIR) analysis confirmed the removal of lignin and hemicellulose. These characteristics highlight its potential as a functional ingredient in food formulations, particularly in meat- and fish-based products that require improved texture and moisture retention. This study demonstrates the valorization of corn stalk waste into a valuable DF source, supporting sustainable resource utilization and the development of clean-label, fiber-enriched food products aligned with circular economy principles.