Abstract: Corn germ meal (CGM) is one of the primary by-products during corn processing. It is frequently underutilized—either used as animal feed or discarded as waste—resulting in resource inefficiency and environmental concerns. Corn fiber gum (CFG), a natural polysaccharide in CGM, can be expected as a promising alternative to synthetic food additives, due to its strong emulsifying, thickening, and antioxidant capabilities. This study aims to systematically evaluate how three common extraction methods—alkaline, enzymatic, and acidic—impact the structural characteristics, functional properties, and antioxidant activities of CFG isolated from CGM. The optimal extraction strategy was identified to maximize the CFG quality and its applicability in the food industry. Prior to CFG extraction, three pretreatments were performed on the CGM: defatting with n-hexane (solid-to-liquid S/L ratio 1:8, 2.5 h, repeated twice), starch removal using α-amylase (enzyme dosage 0.5% w/w, pH6.0, 55 °C, 2 h). Following pretreatment, CFG was extracted via three protocols: alkaline extraction (1% w/v NaOH solution, S/L ratio 1:10, 100 °C), enzymatic extraction (xylanase dosage 1.2% w/w, Ph4.8, 50 °C, 4 hours), and acidic extraction (formic acid-acetic acid-water mixture, volume ratio 3:6:1, 85 °C, 4 h). Post-extraction, all CFG samples were neutralized, concentrated via rotary evaporation (50 °C, 0.08 MPa absolute pressure), precipitated with 95% v/v ethanol (volume ratio 1:4, 4 °C, 12 h), and freeze-dried (-80 °C, 48 h) to yield powdered CFG for subsequent analysis. Comprehensive characterization was performed to compare the extraction. The key indicators were determined: CFG yield, purity (quantified via the phenol-sulfuric acid), molecular weight (determined by gel permeation chromatography GPC), particle size and zeta potential, solubility (assessed at 25 °C in distilled water), rheological properties (evaluated with a rotational rheometer over a shear rate range of 0.1–100 s^-1, 25–80 °C), emulsion stability (tested by preparing oil-in-water O/W emulsions containing 5% v/v soybean oil and 1% w/v CFG, stored for 12 days, and antioxidant activity (measured via total phenolic content TPC using the Folin-Ciocalteu, DPPH radical scavenging activity RSA, and ABTS RSA). Results revealed that there were significant differences in the CFG properties across the three methods. Alkaline extraction achieved the highest CFG yield (19.2±0.96) %, yet the resulting product shared the relatively low purity (64±3.2%) and high molecular weight (296±2.31 kDa). This was attributed to the dissolution of impurities (e.g., lignin and hemicellulose fragments) under strong alkaline conditions. Acidic extraction yielded moderate products: (6.3±0.32%) yield, (62±3.1%) purity, and CFG with large particle size (515.5±7 nm) and solubility (88.9±2.6%)—due likely to the acid-driven polysaccharide degradation and aggregation. In contrast, enzymatic extraction was produced CFG (E-CFG) with the highest purity (68±3.4%) and superior overall functional performance: The smallest molecular weight (169±3.47 kDa) and particle size (381.6±11.45 nm) were enhanced to bind water molecules; The highest absolute zeta potential (-15.44±0.14 mV) was boosted dispersion stability via strong electrostatic repulsion between particles; and the greatest solubility (91.37±2.7%) at 25 °C—a critical advantage for food processing applications requiring rapid dissolution. Rheological analysis further confirmed the E-CFG’s superiority, with the strongest gel-forming capacity (storage modulus, G’, > loss modulus, G”, across the full 25–80 °C temperature range) and typical shear-thinning behavior. Therefore, it was ideal for products like salad dressings and sauces, which required both thickening and pourability. Emulsion testing results demonstrated that the emulsions were stabilized by enzyme-extracted CFG (E-CFG), indicating the superior stability compared with the alkaline- and acidic-extracted CFG. Specifically, E-CFG-stabilized emulsions shared better performance, in terms of droplet size control and resistance to phase separation, and maintained more stable characteristics after extended storage at room temperature (25 °C). In terms of antioxidant activity, the assessments indicated that the E-CFG also possessed a stronger antioxidant capacity, compared with the alkaline- and acidic-extracted CFG. A key factor contributing to E-CFG’s enhanced antioxidant performance was its higher content of total phenolic components, which was closely associated with the free radical scavenging capabilities. This higher phenolic content was supported by E-CFG’s more robust ability to scavenge free radicals, compared with the rest two types of extracted CFG. Monosaccharide composition analysis was conducted via high-performance liquid chromatography (HPLC). It was found that the E-CFG shared the highest arabinose-to-xylose (Ara/Xyl) ratio (0.82±0.01), indicating a more highly branched polysaccharide chain. Pearson correlation analysis confirmed that this structural trait was positively linked to improved solubility and viscosity, indicating the structure-function relationship for CFG. Conclusively, enzymatic extraction was the optimal method to produce the high-quality CFG from CGM. A resulting product was presented with exceptional emulsifying, stabilizing, and antioxidant properties. E-CFG can be expected to fully meet the technical demands of diverse food applications: It acts as a natural emulsifier in yogurt to prevent whey syneresis, a stabilizer in ice cream to improve texture and inhibit ice crystal formation, and an antioxidant in baked goods to extend shelf life by reducing lipid oxidation. Furthermore, the structure-function relationship can also provide a theoretical foundation to optimize the CFG extraction and the high-value utilization of corn processing by-products. Thus, the CGM can be converted from waste to a high-value food additive. This research can support the circular economy in the corn processing industry, thus reducing environmental impact on economic viability.