Aroma comparison of 'Marion' (Rubus sp. L.) and 'Thornless Evergreen' (R. laciniatus L.) blackberries

'Marion' and 'Thornless Evergreen' blackberry volatiles were analyzed by capillary gas chromatography-flame ionization detection (GC-FED) and GC-mass spectrometry (GC-MS). Based on total percentage of FID area 'Thornless Evergreen' contains significantly more alcohols, hydrocarbons, and phenols than the 'Marion'; 'Marion' contains more acids and esters. Both cultivars contained comparable amounts of aldehydes and ketones; alcohols were most abundant. The six most abundant volatiles in 'Marion' were ethanol, acetic acid, hexanoic acid, ethyl acetate, linalool, and 2-heptanol; they totaled 52% of total peak area. In 'Thornless Evergreen' the six most abundant volatiles were 2-heptanol, ethanol, 2,3-butanediol, hexanol, α-pinene, and ethyl acetate; they totaled 43% of total peak area. 'Marion' and 'Thornless Evergreen' blackberry aromas were compared using a pair of extraction and gas chromatography-olfactometry-mass spectrometry (GC-O-MS) methods. One method is based on purge-and-trap (P&T, dynamic headspace) extraction and aroma intensity rating by detection frequency (DetF) and a numeric scale, and the other based on solvent assisted flavor extraction (SAFE) and aroma threshold dilution analysis (AEDA). The parallel use of P&T-DetF GC-0 and SAFE-AEDA provided more representative blackberry volatile compositional data than either alone. Eighty-four compounds were identified; seventy-seven were in 'Marion', and sixty-eight in 'Thornless Evergreen'. Thirty-seven have not been previously reported in blackberry. Fourteen volatiles out of eighty-four were described with aroma descriptors specific to bramble fruit (berry, blackberry, bramble, raspberry); no single compound was unanimously described as "characteristically blackberry". Fresh 'Marion' blackberry aroma has been described as floral, fruity, sweet, caramel-fruity, and woody, while fresh 'Thornless Evergreen' aroma is spicy, green, herbaceous, fruity, and sweet. Except for esters, the cultivars contain comparable numbers of acids, alcohols, aldehydes, furanones, hydrocarbons, ketones, phenolics, sulfur, and Theaspirane compounds. Research data implies some portion of the more floral, fruity, and sweet aroma of the 'Marion' blackberry may be the result of additional esters not shared with the 'Thornless Evergreen' blackberry, yet both cultivars apparently contain five furanones, which are powerful sources of sweet, fruity, and spicy aromas. Aroma reconstitution studies will be the key to resolving the significant aroma profile differences between 'Marion' and 'Thornless Evergreen' blackberries, as characteristic blackberry aroma is apparently a complex formulation of volatiles

Volatile compounds of fruits of raspberry 'Meeker' and blackberry 'Cacanska Bestrna' propagated by standard techniques and in vitro micropropagation

A two-year research was conducted on volatile compounds of raspberry cultivar 'Meeker' and blackberry cultivar 'Cacanska Bestrna' fruits, harvested at full ripeness and collected from plants propagated by both standard vegetative technique (by suckers from adventitious root buds for raspberry and tip layering for blackberry) and in vitro micropropagation. Out of the total number of volatile components, key aromatic components were selected, having a decisive impact on the aroma of raspberry and blackberry fruits. In both experimental years (2011-2012), contents of 48 key aromatic components were compared in the raspberry fruits, whereas 53 key aromatic components were quantified and compared in the blackberry fruits. These components were further classified in alcohols, aldehydes, ketones, acids, esters, terpenes, sesquiterpenes, lactones, C13 norisoprenoids (only in raspberry fruits), hydrocarbons (only in raspberry fruits) and phenols (only in blackberry fruits). No significant differences have been established in the presence of certain volatile aromatic components in the raspberry fruits collected within the same year from plants produced using the standard method, compared to plants obtained by in vitro micropropagation. The same trend was established in blackberry fruits