Extraction of antioxidant and antimicrobial phytochemicals from corn stigma: a promising alternative to valorization of agricultural residues

The discover), of new natural additives from agro-industrial waste is considered an important research topic. This study investigated the feasibility of ultrasound-assisted extraction (UAE) of antioxidant compounds from corn stigma (CS) and the effect of independent variables (time and solid-solvent ratio) and their interaction in the extraction of CS. Results indicated that the UAE method increases the antioxidant activity and reduces the extraction time by 67%. Optimized conditions for the simultaneous extraction of antioxidants and polyphenols from CS were obtained using 5 min and a solid-solvent ratio of 0.05 g mL(-1). The CS extract obtained by UAE was characterized by ESI-ToF-MS and 27 phytochemicals were reported. The extract showed promising antifungal and antibacterial activities against 23 of the studied microorganisms. Therefore, the CS extract obtained by the UAE can be used as a source of bioactive and antimicrobial compounds for use as a functional ingredient in the food and pharmaceutical industry.