Unraveling the impact of extraction methods on functional and structural attributes of Allium sativum L. proteins

With the growing interest in sustainable and functional plant-based proteins, efficient extraction strategies are essential. However, the influence of different extraction methods on garlic ( Allium sativum L.) protein characteristics remains underexplored. This study has addressed this gap by comparing four extraction methods—NaCl-assisted acid precipitation (NA), alkali-soluble alcohol precipitation (AA), ammonium sulfate precipitation (AS), and alkali-soluble acid precipitation (AC)—in terms of yield, composition, structure, and functionality. The AS method exhibited a higher protein yield (78.5 ± 0.4 g/100g), amino acid content (774 ± 2 mg/g), and α-helix proportion (35 ± 2 %), along with the strongest antioxidant capacity (FRAP: 0.55 ± 0.05 mmol Fe 2+ /g). AA resulted in the highest emulsion stability (ESI: 84.5 %) and ABTS + scavenging activity (99.04 % at 4 mg/mL), while AC showed the strongest DPPH radical scavenging (22.1 %). Structural analyses revealed that extraction methods significantly affected particle size, zeta potential, and secondary structure. In conclusion, the AS method offered optimal balance in efficiency and functionality, making it suitable for large-scale preparation of functional garlic protein. Alcohol- and acid-based methods showed potential for specific functional applications. This work provided methodological and theoretical guidance for the targeted development and application of plant-derived proteins in food and nutraceuticals. • Compared 4 garlic protein extraction methods for composition, structure, function. • Ammonium sulfate precipitation gave highest yield, α-helix, and antioxidant capacity. • Alcohol and acid methods improved emulsion stability and radical scavenging capacity. • Provided guidance linking extraction methods with garlic protein performance.