Frozen Marion (Rubus sp. hyb) and Evergreen blackberries (Rubus
laciniatus) (whole berries, berries without seeds, and seeds alone) were
acetone/ chloroform extracted. Phenolics were isolated using C₁₈ cartridges
and polyamide resins, then characterized and measured by reversed-phase
HPLC/diode array spectral techniques. The Polyamide isolated fractions of
Marion berries contained four quercetin glycosides, one kaempferol
glycoside, three acylated quercetin glycosides, (-)-epicatechin, and eight
ellagic acid derivatives. Polyamide isolated fractions of Marion seeds had
several procyanidins (including (+)-catechin and (-)-epicatechin), 11
tentative ellagitannins, and eight ellagic acid derivatives. (-)-Epicatechin and
ellagic acid derivatives were the primary phenolics in blackberry fruits and
seeds. Flavonols were the major component in whole berries, while
procyanidins and ellagic acid derivatives were the primary phenolics in
seeds. No flavonols were found in seeds.
The phenolic profiles of Marion and Evergreen were qualitatively
similar. Evergreen berries contained higher level of (-)-epicatechin, ellagic
acid derivatives, and flavonols than Marion berries. Evergreen seeds were
also higher in procyanidin content than Marion seeds, while Marion seeds
were higher in ellagic acid derivatives. No ascorbic acid was found in any
extracts. The total monomeric anthocyanin content of Marion berries (225
mg of Cyanidin 3-glucoside/100g) was 1.5 times higher than that of
Evergreen berries (154 mg/100g). However, the total phenolics, total
monomeric anthocyanins, oxygen radical absorbing capacity (ORAC), and
ferric reducing antioxidant power (FRAP) values of Marion and Evergreen
berries were not statistically different at the significance level 0.05. The total
phenolics, ORAC, and FRAP values of Marion berries were 844 mg of gallic
acid equivalent (GAE)/100g, 35.5 μmole of Trolox equivalent (TE)/g, and
79.1 μmole of TE/g, respectively. The total phenolics, ORAC and FRAP
values of Evergreen berries were 822 mg of GAE/100g, 34.3 μmole of TE/g,
and 74.2 (μmole of TE/g, respectively. Over all, Marion blackberries were
higher than Evergreen blackberries with respect to phenolic content and
antioxidant capacity.
This study confirmed that blackberries contributed a significant
source of phenolic antioxidants that may have potential health effects.
Blackberry seeds, accounting for 5.0% of the weight of Marion berries and
5.6% of Evergreen berries, had very high phenolic content and antioxidant
capacity; therefore they may be a potential source for nutraceuticals and
natural antioxidants. / Graduation date: 2002
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27424 |
| Date | 12 December 2001 |
| Creators | Siriwoharn, Thanyaporn |
| Contributors | Wrolstad, Ronald E. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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