Sensory, Health and Quality Evaluation of Two Blackberry (Rubus subgenus Rubus) Cultivars From Arkansas and Oklahoma

Berries from two thornless, erect, blackberry (Rubus subgenus Rubus) cultivars, Apache and Ouachita were harvested in summer 2008 from the University of Arkansas Fruit Research Station in Clarksville, Arkansas and a commercial berry farm in Broken Arrow, Oklahoma. Berries were frozen immediately after harvest for future analysis at Oklahoma State University, Stillwater. In fall 2008 and winter 2009, berries were analyzed for soluble solids, weights and dimensions, pH, titratable acidity (as citric acid), antioxidant potential (defined as total phenolic, flavonoid and anthocyanin content), and sensory attributes (including seediness, juiciness, sweetness, acidity and flavor). Soluble solids averaged 9.5% for ‘Ouachita’ from both locations and 10.5 and 10.2% for ‘Apache’ from Oklahoma and Arkansas, respectively. Mean berry weight (g) was 2.8 for Oklahoma ‘Ouachita’, 4.2 for Arkansas ‘Ouachita’, 4.8 for Oklahoma ‘Apache’, and 5.8 for Arkansas ‘Apache’. Blackberry juice pH showed similar results, with Oklahoma ‘Ouachita’ pH of 3.7 and 3.1pH for all others. Titratable acidity (%) for Oklahoma berries was 1.48 for ‘Ouachita’ and 1.12 for ‘Apache’, and 1.38 for ‘Ouachita’ and 1.28 for ‘Apache’ from Arkansas berries. Comparing overall antioxidant potential, ‘Ouachita’ berries had lower content for phenolics and anthocyanins as compared to ‘Apache’. By location, antioxidant potential results were very similar when comparing ‘Ouachita’ from Oklahoma and Arkansas. Oklahoma ‘Apache’ showed higher total phenolics compared to Arkansas ‘Apache’, which had higher flavonoid and anthocyanin content than the Oklahoma ‘Apache’. Results of the sensory panel indicated blackberry cultivar had a significant effect on sweetness, acidity and flavor, but growing location was not significant when averaged over both cultivars. However, ‘Apache’ blackberries from Oklahoma were significantly sweeter than ‘Apache’ berries from Arkansas while ‘Ouachita’ berries from Arkansas had significantly greater ratings for sweetness and acidity than ‘Ouachita’ from Oklahoma. When we compared results for sweetness, acidity and flavor of berries harvested in Oklahoma, ‘Apache’ had significantly higher ratings than ‘Ouachita’.  These results should help growers decide which blackberry cultivars perform better in their specific growing area, whether in Arkansas or Oklahoma.  Additional evaluation is underway to help characterize the winemaking potential of these cultivars.