Enzymatic method for the determination of L-malic acid
Malic acid, both in free and esterified form, is usually present in ripening fruit and is responsible for the astringent taste of the unripe fruit. Its concentration is reduced as it matures. In the process of winemaking, more than 30% of the malic acid is transformed by a process of fermentation in lactic acid (malolactic fermentation) that helps to reduce the initial acidity of the must. Control of the malic acid level is necessary to maintain the desired taste, acidity and astringency characteristics of wine.