Volatile compounds and sensory characteristics of various instant teas produced from black tea.

Various instant teas produced differently from black tea [freeze-dried instant tea (FDIT), spray-dried instant tea (SDIT), and decaffeinated instant tea (DCIT)], were compared for their differences in volatile compounds as well as descriptive sensory analysis (DSA). A total of 63 volatile compounds in all tea samples (eight aldehydes, ten alcohols, nine ketones, five esters, eight acids, ten terpenes/terpenoids, ten furans/furanones, two pyrroles, and one miscellaneous compound) were tentatively identified. Black tea, FDIT, SDIT, and DCIT contained 60, 55, 47, and 40 volatile compounds, respectively. Ten flavour attributes such as after taste, astringency, bitter, caramel-like, floral/sweet, green/grassy, hay-like, malty, roasty, and seaweed were identified. Intensities for a number of flavour attributes (except for caramel-like in SDIT and bitter and after taste in DCIT) were not significantly different (p>0.05) among tea samples. The present study suggests that instant teas can also be used as good alternative to black tea.

Antioxidant properties, phenolic composition and potentiometric sensor array evaluation of commercial and new blueberry (Vaccinium corymbosum) and bog blueberry (Vaccinium uliginosum) genotypes.

Antioxidant properties of juices of newly bred and known blueberry (Vaccinium corymbosum) genotypes and wild bog blueberry (Vaccinium uliginosum) were evaluated by ABTS(+) scavenging capacity (RSC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), total phenolic content (TPC) and total anthocyanin content (TAC) assays. TPC varied in the range of 0.85-2.81 mg gallic acid equiv./mL, RSC, FRAP and ORAC values were 6.38-20.9, 3.07-17.8 and 4.21-45.68 µmol Trolox equiv./g, respectively. New blueberry genotypes and bog blueberry demonstrated stronger antioxidant properties and TAC than other studied genotypes. The content of quinic (203-3614 µg/mL), chlorogenic (20.0-346.8 µg/mL) acids and rutin (0.00-26.88 µg/mL) measured by UPLC/ESI-QTOF-MS varied depending on the genotype. Juices were evaluated by electronic tongue; PCA score plot showed that the method discriminates different genotypes although some juice samples were located very closely and overlapping. Significant differences were observed between L(∗), a(∗), b(∗) colour parameters of some genotypes.

Antioxidant properties and polyphenolic compositions of fruits from different European cranberrybush (Viburnum opulus L.) genotypes.

Antioxidant properties of fruit juices of six Viburnum opulus genotypes were evaluated by DPPH, ABTS(+) radical scavenging capacity (RSC), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and Folin-Ciocalteu total phenolic content (TPC) assays. TPC varied in the range of 5.4-10.6 mg gallic acid equivalents/g, RSC (ABTS(+)), FRAP and ORAC values were 31.9-109.8, 32.3-61.8 and 141.6-260.4 µmol trolox equivalents/g, respectively. V. opulus var. sargentii fruit juice was a remarkably stronger antioxidant than the other five V. opulus genotypes. The content of chlorogenic acid (the main phenolic compound in berry juices) depending on plant cultivar varied in the range of 0.54-6.93 mg/ml. The RSC of individual constituents was measured by the on-line HPLC-UV-DPPH method: chlorogenic acid was the dominant radical scavenger in V. opulus P3 (74%), while epicatechin and catechin (the main antioxidants in V. opulus var. sargentii) contributed to 40% and 23% of the total RSC for the sargentii genotype. Nine constituents were identified in V. opulus juice by using ultra high performance liquid chromatography coupled to quadruple and time-of-flight mass spectrometers (UPLC-QTOF-MS). In general, the study demonstrated that V. opulus var. sargentii followed by V. opulus P3 and V. opulus var. americanum possessed the highest antioxidant capacity. The obtained results may assist in selecting the most valuable V. opulus genotypes for the production of fruits possessing strong antioxidant capacity and containing beneficial phenolic constituents.

Characterization of Aronia melanocarpa volatiles by headspace-solid-phase microextraction (HS-SPME), simultaneous distillation/extraction (SDE), and gas chromatography-olfactometry (GC-O) methods.

The profiles of volatile constituents of berry fruit of two Aronia melanocarpa genotypes were evaluated by headspace-solid-phase microextraction (HS-SPME), simultaneous distillation and extraction (SDE), and gas chromatography-olfactometry (GC-O). In total, 74 volatile compounds were identified in chokeberry juice, 3-penten-2-one, 3,9-epoxy-p-menth-1-ene, and benzaldehyde being the most abundant constituents; however, their percentage concentrations were remarkably different in the HS-SPME and SDE profiles. Twenty two aroma-active compounds were detected and characterized by the trained panelists in HS-SPME using GC-O detection frequency analysis. Olfactometry revealed that ethyl-2-methyl butanoate, ethyl-3-methyl butanoate, ethyl decanoate ("fruity" aroma notes), nonanal ("green" notes), unidentified compound possessing "moldy" odor, and some other volatiles may be very important constituents in formation of chokeberry aroma of both analyzed plant cultivars.