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

Blackberries have been enjoyed for their delicious flavor and high nutritional value for hundreds of years. In North America, blackberries were cultivated since 1850-1860. Blackberries have their characteristic and unique aromas depending on the cultivar and growing conditions. The objective of this study was to evaluate the impact of seasonal variation and growing environment on blackberry aroma. Volatile compositions of 'Marion' and 'Thornless Evergreen' blackberries from three growing seasons were analyzed using gas chromatography-flame ionization detection (GC-FED) and GC-mass spectrometry (GC-MS). Seasonal variations were observed for some volatile compounds in these two blackberry cultivars. In 'Marion', the compounds were mainly acids, while in 'Thornless Evergreen', they were mainly acids, alcohols, and a few terpenoids. Although seasonal variations were present, it was generally observed that the most abundant volatiles in 'Marion' blackberry were acetic, 2/3-methylbutanoic, hexanoic and decanoic acids and linalool, whereas the most abundant volatiles in 'Thornless Evergreen' were 2-heptanol, hexanol, octanol, α-pinene, nopol and/p-cymen-8-ol. Compared with 'Marion', 'Thornless Evergreen' contained significantly more total volatiles, especially in alcohols, terpenoids and phenols, whereas 'Marion' contained more organic acids. Odor Activity Values (OAVs) were used to determine the most potent odorants in each cultivar. The compounds with high odor activity values (OAV > 10) in 'Marion' were ethyl hexanoate, β-ionone, linalool, 2-heptanone, 2-undecanone, α-ionone and hexanal. The compounds with high odor activity values (OAV > 10) in 'Thornless Evergreen' were ethyl hexanoate, 2-heptanone, ethyl 2-methylbutanoate, 2-heptanol, 3-methylbutanal, α-pinene, limonene, p-cymene, linalool, t-2-hexenal, myrtenol, hexanal, 2- methylbutanal and sabinene. To investigate the influence of growing environment on blackberry aroma, aroma extraction dilution analysis (AEDA) was employed to characterize the aroma profile of 'Chickasaw' blackberries from two growing regions in United States: Oregon and Arkansas. Eighty-seven odorants were detected in the two berries, in which seventy-seven could be identified. Comparative AEDA analysis showed that the berries grown in these two regions had similar aroma compositions, however, those odorants had various aroma impacts in each region. The compounds with high FD factors in Oregon's 'Chickasaw' were ethyl butanoate, linalool, methional, trans,cis-2,6-nonadienal, cis-l,5-octadien-3-one, and 2,5-dimethyl-4-hydroxy- 3(2H)-furanone, whereas in the 'Chickasaw' grown in Arkansas, they were ethyl butanoate, linalool, methional, ethyl 2-niethylbutanoate, β-damascenone and geraniol. The flavor formation in 'Chickasaw' blackberries was largely influenced by their growing environment. / Graduation date: 2005

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