The Release of Bound Phenolics to Enhance the Antioxidant Activity of Cornmeal by Liquid Fermentation with Bacillus subtilis

• Published in: Foods Vol. 14; no. 3; p. 499
• Main Authors: Zhang, Ping, Zhang, Jialan, Li, Li, Gu, Tong, Chen, Suo, Wang, Jinsong, Gao, Mengxiang
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 04.02.2025; MDPI
• Subjects: Acids; Amino acids; Analysis; antioxidant activity; Antioxidants; Bacillus subtilis; Bioavailability; Bioflavonoids; Biological activity; bound phenolics; Calorimetry; carbohydrate-hydrolyzing enzymes; Carbohydrates; Caustic soda; Cellular structure; Cellulase; Chemical bonds; cornmeal; Differential scanning calorimetry; Enzymatic activity; Enzymes; Fermentation; Fermented food; Flavones; Flavonoids; Food matrix; Food processing; Fourier transforms; Glucosidase; Infrared analysis; Infrared spectroscopy; Microorganisms; Phenolic acids; Phenols; Polyphenols; Product introduction; Scanning electron microscopy; X-ray diffraction; Xylanase; β-Glucosidase; China; Japan; bound phenolics; fermentation; cornmeal; carbohydrate-hydrolyzing enzymes; Bacillus subtilis; antioxidant activity
• DOI: 10.3390/foods14030499
• ISSN: 2304-8158

This study investigated the influence of Bacillus subtilis fermentation on the composition of phenolic substances and antioxidant activity in cornmeal. The results indicate that the fermentation process significantly increased both the total phenolic content (TPC) and total flavonoid content (TFC). After 5 days of fermentation, the TPC rose from 31.68 ± 1.72 mg/g to 39.46 ± 2.95 mg/g, representing a 24.56% increase, while the TFC increased from 2.13 ± 0.11 mg/g to 7.56 ± 0.29 mg/g, marking a 254.93% increase. Additionally, the proportion of free phenolic compounds in cornmeal increased from 20.24% to 83.98%, while the proportion of bound phenolic compounds decreased from 79.76% to 16.02%. Furthermore, the hydrolytic enzyme activities of cellulase, β-glucosidase, and xylanase were significantly correlated with the free phenolic content (FPC) (r > 0.85, p < 0.05), indicating their crucial role in releasing free phenolic compounds from cornmeal. Employing scanning electron microscopy, differential scanning calorimetry, X-ray diffraction, and Fourier-transform infrared spectroscopy analyses, we inferred that the carbohydrase enzymes produced by the microorganisms disrupted the cellular structure of cornmeal and weakened the interactions between bound phenolics and the food matrix, thereby facilitating the release of phenolic compounds. This release resulted in an overall increase in the antioxidant activity of the cornmeal. The study provided a novel approach to enhancing the bioavailability of phenolic acids in cornmeal, indicating the potential benefits of fermentation in food processing.