Among Vaccinium species, blueberries (Vaccinium myrtillus L.) and lingonberries (Vaccinium vitis-idaea) are popular in the human diet. In this study, total phenolic, total flavonoid and total monomeric anthocyanin contents in the ethanol-water extracts of blueberry and lingonberry fruits grown wild in the forests in the central region of Poland were assayed. Antioxidant activities of the extracts from each plant were also evaluated for scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and reducing power by cupric reducing antioxidant capacity (CUPRAC) method. Total phenolics in the blueberry extracts ranged from 4.58 to 5.28 mg GAE CE/g fw. The extracts from lingonberry fruits contained higher total contents of phenolic compounds (5.82–7.60 mg GAE/g fw) as well as total flavonoids (5.22–6.47 μmol CE/g fw) than those from blueberries (3.74–4.18 μmol CE/g fw). For the total monomeric anthocyanin contents, the blueberry extracts presented significantly higher values (3.01–3.93 mg cyanidin-3-glucoside (C3G) equivalent/g fw) in comparison to the lingonberry extracts (0.32–0.47). Blueberry extracts exhibited higher antioxidant activity measured by both assays in comparison to lingonberry extracts. Water extracts from fresh and dried fruits also exhibited significant antioxidant activities for both types of berries. Considering the health benefits that have been associated with polyphenolic consumption, these fruits could appear as a good source of this group of phytochemical compounds for their direct consumption or their use as ingredients for the design of new food products or food supplements.Electronic supplementary materialThe online version of this article (10.1007/s11130-017-0640-3) contains supplementary material, which is available to authorized users.

ObjectiveAntioxidant properties of the water extracts of the commercial bagged fruit and flavoured black teas were evaluated and compared with typical black teas of C. sinensis.MethodsFolin–Ciocalteu (FC) assay, cupric ion reducing antioxidant capacity (CUPRAC) and DPPH radical method were used for these purposes. The content of selected flavonoids and phenolic acids was also determined by high-performance liquid chromatography with tandem mass spectrometry in the negative electrospray ionization mode.ResultsFlavoured black teas contain significantly higher level of catechins, quercetin, and rutin, while the content of chlorogenic and caffeic acids as well as naringin and hesperidin was higher in fruit teas. Supplementation with these flavonoids could reduce blood glucose. In FC and DPPH assays, the antioxidant properties of studied tea infusion increases in the order: fruit tea < flavoured black tea > premium black tea, while in CUPRAC method, some aromatized teas exhibit the highest antioxidant properties. Tea infusions with nice smell of fruits would also support the human diet with some source of antioxidants.

The extraction efficiency of major classes of phenolics from lingonberries grown in the central region of Poland was evaluated. The ethanol–water solution (60:40, v/v) resulted in the highest extraction yields; however, the results obtained for ethyl acetate were only slightly lower. Total phenolics estimated by Folin-Ciocalteu assay ranged from 468 to 661 mg of GA/100 g fresh weight (fw), while total flavonoids were in the range of 53.2–67.8 μmol/100 g fw. Both solvents exhibited comparable potential for monomeric anthocyanin extraction (26.1–43.0 mg CGE/100 g of fw). The content of several minerals in these fruits and in soil collected from the same places were compared. The essential metal concentrations in all samples increased in the following order: Cr < Cu < Zn < Fe. The levels of toxic elements (Cd, Pb) were acceptable to human consumption for most tested samples. The ethanol-water extracts exhibited the highest scavenging activity against 1,1-diphenyl-2-picryl-hydrazyl (DPPH) radicals, while the highest reducing capacity evaluated by cupric reducing antioxidant capacity (CUPRAC) was obtained for ethyl acetate extracts.

Extraction efficiency of total polyphenols and flavonoids from bark oak (Quercus robur L.) grown in the central region of Poland was evaluated. The total phenolics of water and 60% ethanol and extracts were in the range of 55.4-60.4 and 71.0-79.3 mg gallic acid/g of bark, respectively, while the total flavonoid content in these extracts were determined in the range of 35.1-38.0 and 72.0-78.4 mg catechin/g. The hydroalcoholic extracts exhibited higher DPPH radical scavenging activity than BHT (butylated hydroxytoluene), popular food additives.

The studied teas, besides having a relatively high content of catechins, also contain naringin and hesperidin, which are not present in 'pure' green tea. It is important to run multiple assays to get a better estimate of the antioxidant capacity of a given sample.