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.
Chilling influences the growth and metabolism of plants. The physiological response and acclimatization of genotypes in relation to stress stimulus can be different. Two sage cultivars: 'Icterina' and 'Purpurascens' were subjected to 4 °C and 18 °C (control), and sampled between the 5th and 14th day of the treatment. Ascorbate peroxidase (APX) activity was up-regulated in chilled 'Purpurascens' on the 14th day, while guaiacol peroxidase (GPX) activity increased on the 10th and 12th day in relation to the control. GPX activity of the control 'Icterina' was frequently higher than chilled plants, and chilling did not affect APX activity of that cultivar. Catalase activity remained stable in both sage cultivars. Chilled 'Purpurascens' showed a significant increase in total phenolics contents on the 5th, 7th, and 12th day and in total antioxidant capacity on the 5th and 10th day as compared to the control for respective sampling days. Higher malondialdehyde content was found in chilled plants on the 12th, or 14th day, differences reached 26-28% of the controls. Chilling caused significant decrease in dry matter content. The stress response was more stable and effective in 'Icterina', while more dynamic changes were found for 'Purpurascens'. Based on our results, we propose to use 'Purpurascens' for targeted stress-induced studies and 'Icterina' for field applications.
