Conversion of Phenolic Constituents in Aqueous Hamamelis virginiana Leaf Extracts During Fermentation

Abstract

The present study broadens the knowledge on conversion processes in aqueous fermented extracts containing tannins, flavonol glycosides and hydroxycinnamic acids. In particular, the analogy between the microbial metabolism of phenolics from fermented Hamamelis extracts, fermented sourdough by heterofermentative lactic acid bacteria or conversion of phenolics by the human microbial flora is indicated.

Non-anthocyanin phenolic compounds and antioxidant activity of beverages obtained by gluconic fermentation of strawberry

“…Our data are in accordance with Pérez-Gregorio, Regueiro, Alonso-González, Pastrana-Castro, and Simal-Gándara (2011) who reported hydroxycinnamic acid derivatives increase after alcoholic fermentation of mulberries (Morus nigra). In addition, the presence of hydroxybenzoic acid may indicate the degradation of other hydroxycinnamic compounds by fermentation, as reported by Duckstein et al (2012).…”

“…Enzymes, like the esterase tannase, are able to hydrolyze ester bonds to release gallic acid and sugar moieties. Bacteria, yeast or fungi in the fermentation process can produce this enzyme (Duckstein, Lorenz, & Stintzing, 2012). Epicatechin gallate was considered another releaser of gallic acid.…”

Studies into the phenolic patterns of different tissues of pineapple (Ananas comosus [L.] Merr.) infructescence by HPLC-DAD-ESI-MS n and GC-MS analysis

“…After the addition of 0.2 mL of the silylation reagent [14], the sample was flushed with nitrogen and heated to 105°C held for 45 min in a 10-mL Pyrex vial sealed with a PTFEcoated closure [20]. The solutions were allowed to cool to room temperature and centrifuged for 5 min at 5000×g prior to GC-MS analysis [21,22].…”

“…A number of related caffeoyl(2, 4 and 8), p-coumaroyl(5,12,17 and 24) and feruloyl(10,20,22,23 and 31) derivatives were tentatively assigned. Compounds 2, 4 and 8 revealed UVabsorption maxima at 326-327 nm (shoulder at 295 nm) and common pseudo-molecular ions [M-H] − at m/z 371.…”

The Effect of Bioprocessing on the Phenolic Acid Composition and Antioxidant Activity of Wheat Bran

“…In particular, protocatechuic acid was one of the most important intermediates through which diverse aromatic compounds engaged in ring fission via the tricarboxylic acid cycle (Venturi et al 1998). Quercetin, catechin, and caffeic acid are known to form 3,4-dihydroxybenzoic acid via multistep conversion of 3,4-dihydroxyphenyl-propionic acid (Gross et al 2010;Duckstein et al 2012). Side-chain β-oxidations of cinnamic and trans-p-coumaric acids, for instance, yield benzoic and protocatechuic acids, respectively (Peng et al 2003), and dealkylation reactions of trans-pcoumaric acid yield caffeic acid (Torres y Torres and Rosazza 2001).…”