Untargeted Metabolomics of Fermented Rice Using UHPLC Q-TOF MS/MS Reveals an Abundance of Potential Antihypertensive Compounds

Abstract

Enzyme treatment and fermentation of cereals are known processes that enhance the release of bound bioactive compounds to make them available for bioactivity. In this study, we tested the angiotensin converting enzyme (ACE) inhibitory ability of destarched rice, Prozyme 2000p treated destarched rice (DP), and fermented DP samples. Prozyme 2000p treatment increased the ACE inhibitory ability from 15 ± 5% to 45 ± 3%. Fermentation of the Prozyme 2000p treated samples with Enterococcus faecium EBD1 significantly increased the ACE inhibitory ability to 75 ± 5%, while captopril showed an ACE inhibition of 92 ± 4%. An untargeted metabolomics approach using Ultra-high-performance liquid tandem chromatography quadrupole time of flight mass spectrometry revealed the abundance of vitamins, phenolic compounds, antioxidant peptides, DPP IV inhibitory peptides, and antihypertensive peptides in the fermented samples which may account for its strong ACE inhibition. Although fermented DP had decreased fatty acid levels, the amount of essential amino acid improved drastically compared to destarched rice. Our results show that fermenting Prozyme-treated destarched rice with Enterococcus faecium EBD1 generates abundant bioactive compounds necessary for developing antihypertensive functional foods.

Untargeted Metabolomics Analysis Using FTIR and UHPLC-Q-Orbitrap HRMS of Two Curculigo Species and Evaluation of Their Antioxidant and α-Glucosidase Inhibitory Activities

“…The heatmap model’s color intensity was used to depict the relative abundance in the sample extract of Curculigo species, and its variation can tell us about the compounds diversity in the plant [ 29 ]. We used the peak area from the detected metabolites because it is widely accepted that the peak area of an analyte in a chromatogram is directly proportional to its concentration [ 30 ].…”

“…PLS, as a supervised pattern recognition method, is often used to correlate medicinal plants’ biological activities with chromatographic or spectroscopic data (peak area or peak and absorbance value) [ 15 , 30 , 37 ]. The parameters used to create the PLS model are latent variables (LV), and its full cross-validation was applied for data validation and avoiding overfitting [ 38 , 39 ].…”

“…( ) using peak areas data (*.csv format) from all compounds detected in the adduct type ([M + H] + and [M − H] − ) of each organ of Curculigo species. For hierarchical clustering analysis, distance measures using Euclidean, clustering algorithms using complete, and standardization using autoscale were chosen [ 30 , 47 ].…”

Untargeted Metabolomics of Korean Fermented Brown Rice Using UHPLC Q-TOF MS/MS Reveal an Abundance of Potential Dietary Antioxidative and Stress-Reducing Compounds

“…ABTS activity was measured as described by Ofosu et al (2020) [21] with some modification. ABTS radical cation reagent was formed by the reaction of 7 mmol/L ABTS stock solution with 2.45 mmol/L potassium persulfate stock solution (1:1, v/v).…”

The Health Benefits of the Bioactive Compounds in Foods

“…Besides, there are other processes such as enzyme treatment and fermentation of cereals that enhance the release of bound bioactive compounds and make them available for bioactivity. Authors of [ 4 ] found that enzyme-treated destarched rice samples with subsequent fermentation contained known antihypertensive phenolic compounds and peptides that make these samples a promising material for developing cheap antihypertensive foods.…”