Origin of Wine Lignans.

Plant lignans possess several properties beneficial for human health and therefore, increasing their contents in foods and beverages is desirable. One of the lignan sources in human diet is wine. To elucidate the origin of lignans contained in wine, LC-MS was used to analyze resinol-related lignans in must, seeds, stems, and wine prepared using stainless steel tanks, oak barrels, and Qvevri (clay vessel). White wines aged in stainless steel tanks contained significantly lower amounts of lignan aglycones (20-60 µg/L) than red and Qvevri wines (300-500 µg/L). Generally, white wines aged in stainless steel tanks contained only low amounts of isolariciresinol and matairesinol. Qvevri wines and red wine aged in stainless steel tank contained up to five lignan compounds and in wine aged in oak barrel, six different lignans were identified. Consistently, only low concentration of isolariciresinol has been found in must, whereas more lignan compounds have been found in grape seeds (isolariciresinol, secoisolariciresinol, and pinoresinol) and stems (isolariciresinol and syringaresinol). Consequently, we conclude that lignan content in wine can be increased by maturation in contact with grape berries, seeds, or stems or with wood.