RESUMEN
The decarboxylation of the corresponding amino acids by microorganisms leads to the formation of biogenic amines (BAs). From a toxicological point of view, BAs can cause undesirable physiological effects in sensitive individuals, particularly if their metabolism is blocked or genetically altered. The current study aimed to monitor and evaluate the content of eight biogenic amines (BAs) in 232 samples of wines (white, rosé, red) produced in the Central European region (Zone B). White wines (180 samples), rosé wines (17 samples), and red wines (35 samples) were analyzed. High-performance liquid chromatography equipped with a ultraviolet-visible diode array detector (UV/VIS DAD) was applied to identify and quantify the BAs present in wines. In general, histamine (HIS), tyramine (TYM), putrescine (PUT), cadaverine (CAD), phenylethylamine (PEA), spermine (SPN) and spermidine (SPD) were detected in all tested wine samples. Tryptamine (TRM) was not present in any of the samples examined. In white and red wines, SPD, TYM, and PUT were most often detected. Regarding rosé wines, the three major BAs were SPN, TYM, and CAD. The BA content in red wines was generally higher than in rosé and white wines. However, HIS concentrations above the recommended limit of 10 mg/L were detected in 9% of the red wine samples. In addition, alarming levels of PUT, HIS, TYM, and PEA, with serious potential impact on consumer health, were recorded in two red wine samples. On the whole, the presence and concentrations of BAs in wine should be constantly evaluated, primarily because alcohol intensifies the hazardous effects of BAs.
RESUMEN
This study investigates the effects of in vitro digestion on the antioxidant activity and release of phenolics, xanthine alkaloids, and L-theanine contents of matcha. It establishes digestibility values between 61.2-65.8%. Considering native matcha, the rutin content (303-479 µg/g) reached higher values than catechin (10.2-23.1 µg/g). Chlorogenic acid (2090-2460 µg/g) was determined as predominant. Rutin, quercetin, ferulic, ellagic, and caffeic acid were the least-released phenolics, and their remaining residues reached 76-84%. Protocatechuic, hydroxybenzoic acid, epigallocatechin, and epigallocatechin-3-gallate were the best-released phenolics, with the remaining residues under 1%. Caffeine, L-theanine, and theobromine contents in native matcha reached 16.1, 9.85, and 0.27 mg/g, respectively. Only caffeine (3.66-5.26 mg/g) and L-theanine (0.09-0.15 mg/g) were monitored in the undigested residue, representing 13 and 0.1% of the remaining part, respectively. A chemiluminescence assay showed that water-soluble antioxidants showed significant antioxidant activity in native matcha, while lipid-soluble compounds showed higher antioxidant activity in the undigested samples. Cinnamic and neochlorogenic acids were determined as the main contributors to the ACW values in the undigested matcha, epicatechin, and quercetin in the ACL fraction. The application of the digestion process reduced the antioxidant activity by more than 94%. SEM has proved specific digestion patterns of in vitro digestibility of matcha.
RESUMEN
Matcha was analysed for its chemical composition, fibre, vitamin C, caffeine and chlorophyll contents. Flavonoids and phenolics, phenolic profiles and antioxidant activity both in water and methanol solutions were determined. In vitro digestibility was established. To understand the contribution of individual substances to antioxidant activity or digestibility their mutual correlations were evaluated. Crude fibre (10.7-17.5%), neutral-detergent fibre (30.7-42.8%) and organic matter digestibility values (59.4-69.7%) showed positive correlations, in contrast to protein contents (20.3-35.0%). It seems that chlorophyll b was a stronger contributor to antioxidant activity than chlorophyll a. The highest contents of flavonoids (99-139 mg RE/g) and phenolics (169-273 mg GAE/g) were determined in methanol fractions. High concentrations of chlorogenic (up to 4800 µg/g), sinapic (up to 1400 µg/g) and gallic acids (up to 423 µg/g) were recorded. Kaempferol and rutin were not proved as significant contributors to antioxidant activity.