The influence of cultivar and maturity on polyphenolic composition and
antioxidant activity was investigated by UV-Visible spectrophotometry and
analytical high performance liquid chromatography (HPLC) in commercially
important blackberry cultivars and selections. The anthocyanin pigments changed
tremendously with ripening. Total anthocyanins increased from 74.7-317 mg/100g
fw from underripe to over ripe for 'Marion', and from 69.9-164 mg/100g fw for
'Evergreen'. Total phenolics did not show marked change with maturity with
values slightly decreasing from underripe to ripe. Antioxidant activities, while
increasing with ripening, did not show the noticeable change that total
anthocyanins exhibited. The total phenolic and total anthocyanin contents varied
greatly among 11 cultivars. Total anthocyanins ranged from 131-256 mg/100g fw (mean = 198), total phenolics from 682-1056 mg GAE/100g fw (mean = 900),
ORAC from 37.6-75.5 μmolTE/g fw (mean = 50.2), and FRAP ranged from 63.5-
91.5 μmolTE/g fw (mean = 77.5). Four blackberry cultivars were found to be
higher in total anthocyanins and total phenolics than 'Marion' and 'Evergreen', the
predominant commercial cultivars in the Pacific Northwest. The results from these
studies confirmed that blackberries are a good source of natural antioxidants and
colorant, and demonstrated the potential for obtaining new cultivars with high
pigment/phenolic content through classical plant breeding.
The investigation on the incidence of haze and sediment formation revealed
that the sediment in the commercial reconstituted 'Evergreen' blackberry (CRE)
juice was composed of ellagic acid, protein, and unidentified compounds. The
qualitative tannin and protein-tannin haze test indicated that the sediment was
predominantly tannin or protein-tannin complexes. Nitrogen determination showed
the sediment to be 6.69 ± 2.21% (w/w) protein on a dry weight basis. Almost all of
the extractable material was identified as ellagic acid by HPLC and LC-MS. The
ellagic acid content of the wet sediment was 0.05 g/100g while it was 7.41 g/100g
in freeze-dried sediment. Tannase enzyme did not significantly decrease the
concentration of ellagitannins in 'Marion' blackberry juice in this study. / Graduation date: 2004
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/27065 |
| Date | 22 April 2004 |
| 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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