'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. / Graduation date: 2004
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27136 |
| Date | 19 June 2003 |
| Creators | Klesk, Keith |
| Contributors | Qian, Michael |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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