Identification by mass spectrometry of new compounds arising from the reactions involving malvidin‐3‐glucoside‐(O)‐catechin, catechin and malvidin‐3‐glucoside

摘要: RATIONALE: The aim of this work was to study the putative reactions that could occur in red wines between malvidin-3glucoside-(O)-catechin (mv3glc-(O)-cat) adduct and catechin (cat) or malvidin-3-glucoside (mv3glc) presence acetaldehyde. METHODS: Mv3glc-(O)-cat (1 mM) incubated with (or mv3glc) acetaldehyde (molar ratio 1:4:10) 12% ethanol/water at pH 3.2, protected from light placed oven 30 C. formation new compounds monitored by liquid chromatography-diode-array detection/electrospray ionization mass spectrometry (LC-DAD/ESI-MS) analysis positive negative ion mode. RESULTS: LC-DAD/ESI-MS characterization allowed confirmation structures methylmethine-linked cat-mv3glc-(O)-cat ([M–H] – m/z 1097) mv3glc-mv3glc-(O)-cat ([M] + 1301) adducts. CONCLUSIONS: studies performed model solutions showed colorless mv3glc-(O)-cat can undergo some characteristic anthocyanins flavan-3-ols wine forming methylmethine-bridged compounds. Copyright © 2012 John Wiley & Sons, Ltd. Red is a complex matrix where polyphenolic such as (e.g. catechins procyanidins) play major role its organoleptic properties (color flavor). However, these are very susceptible transformations during processing storage. Therefore, several chemical take place anthocyanins, also small molecules(pyruvicacid,acetaldehyde,acetoaceticacid,etc.)yielding stable anthocyanin-derived pigments pyranoanthocyanins like vitisin A, B, methylpyranoanthocyanin, etc.) which contribute modification sensorial wines. [1–3] Among involving polyphenols, direct acetaldehyde-mediated condensations have been widely studied. [4–12] One first described polymerization reaction mediated acetaldehyde, [4,5,7,13] essentially by-product ethanol oxidation. [14] Acetaldehyde arise yeast metabolism alcoholic fermentation. This kind leads purple-red anthocyanin-flavan-3-ol linked methylmethine bridges (being their lmax batochromatically shifted genuine anthocyanins). Direct originate dimeric-type flavanol-(4,8)-anthocyanin (F-A) anthocyanin-(4,8)-flavanol (A-F)