Evaluation of the Antioxidant Properties of Free and Bound Phenolic Acids from Native and Malted Finger Millet (Ragi, Eleusine coracana Indaf-15)

Abstract

Free and bound phenolic acids were isolated from native and malted finger millet (ragi, Eleusine coracana Indaf-15), and their antioxidant properties were evaluated. Protocatechuic, gallic, and caffeic acids were found to be the major free phenolic acids. A 3-fold decrease was observed in protocatechuic acid content, whereas the decrease was marginal in the case of caffeic acid upon 96 h of malting. However, the contents of other free phenolic acids such as gallic, vanillic, coumaric, and ferulic acids increased. Ferulic, caffeic, and coumaric acids were found to be the major bound phenolic acids, and a 2-fold decrease was observed in their contents upon 96 h of malting. The antioxidant activity of a free phenolic acid mixture was found to be higher compared to that of a bound phenolic acid mixture. An increase in antioxidant activity coefficient was observed in the case of free phenolic acids from 770.0 +/- 7.8 to 1686.0 +/- 16.0, whereas the same was decreased from 570.0 +/- 6.0 to 448.0 +/- 4.5 in bound phenolic acids upon 96 h of malting. Therefore, the antioxidant capacity of phenolic acids changes during the malting of ragi.

Involvement of Secondary Metabolites in Response to Drought Stress of Rice (Oryza sativa L.)

“…For example, Oki et al [34] observed that radical-scavenging ability in red-hulled and black-hulled rice depended on the concentrations of proanthocyanidins and anthocyanins, respectively. During the process of finger millet malting, the contents of phenolic acids were changed, reflecting their antioxidant capacity [35]. The high levels of flavonols, quercetin and kaempferol contents were associated with enhanced stress tolerance capacity of white clover under UV-B radiation and drought conditions [31].…”

Simultaneous GC-MS Determination of Free and Bound Phenolic Acids in Slovenian Red Wines and Chemometric Characterization

“…[1][2][3][4] Generally, it is believed that consumption of plant phenolics decreases the risk of diseases related to oxidative stress. 5 Wine, as a complex matrix containing several hundreds of different chemical compounds, 6,7 presents an analytical challenge, especially for identification and quantification of compounds in low concentrations.…”

A Review of the Phytochemistry and Pharmacology of Eleusine coracana Linn (Poaceae): A Popular Nigerian Edible Grain

“…In the study, 50 µg/mL of the seed coat extract showed higher (86 %) antioxidant activity when compared to whole flour (27%) at the same concentration. Subba Rao and Muralikrishna, 44 also investigated the antioxidant activity of free and bound phenolic acids in native and malted finger millet extracts. Results of the study showed that free phenolic acids in the malted extract exhibited higher antioxidant activity coefficient (770.00 ± 7.8) compared to the bound phenolic acids (570.0 ± 6.0).…”