Anthocyanin and flavonol glycosides of various blackberry, blueberry and red wine grape genotypes were identified and measured by a high-performance liquid chromatographic (HPLC) separation method with photodiode array (PDA) and mass spectrometric (MS) detection. With this method, two distinct elution regions of anthocyanins and flavonols were obtained with near baseline separation of most compounds. Blackberry, blueberry and red wine grape genotypes varied markedly in total anthocyanins and total flavonols as well as oxygen radical absorbance capacity (ORAC). The respective ranges of total anthocyanin (TA) and total flavonol (TF) contents of tested samples were: blackberries, 1143.9-2415.4 and 102.0-160.2 mg kg −1 ; blueberries, 1435.2-8227.3 and 172.5-327.5 mg kg −1 ; and red wine grapes, 380.9-7904.7 and 21.0-322.2 mg kg −1 . Antioxidant activities and contents of total anthocyanins and total flavonols in blackberries, blueberries and red wine grapes were highly correlated, with linear relationships between ORAC and TA (r xy = 0.94) and TF (r xy = 0.90) for grapes, TA (r xy = 0.95) for blueberries and TA (r xy = 0.74) for blackberries.

No abstract

Blueberry fruits from five commercial cultivars and 13 breeding selections grown at the same locations over two growing seasons were analysed for total phenolics (TPH), total anthocyanins (ACY), total hydroxycinnamic acids (HCA), total flavonols (FLA), fruit weight and oxygen radical-absorbing capacity (ORAC). Variation in ORAC, TPH, ACY, HCA, FLA and fruit weight among genotypes was much greater than that observed between growing seasons, indicating that genetics plays a more important role than growing season in influencing ORAC and phenolic content in blueberries. Significant main effects for growing season and genotype × growing season observed for ORAC, ACY, HCA and fruit weight demonstrate that environmental growing conditions can impact levels of phenolics and ORAC in blueberries and that certain genotypes vary in their capacity to synthesise phenolics under different growing conditions. In general, genotypes with smaller berries had higher ORAC values and levels of TPH, ACY, HCA and FLA than large-berried genotypes. Over both growing seasons, ORAC correlated highly with TPH, ACY, HCA and FLA, while fruit weight correlated inversely with all phenolics measured. Our results indicate that blueberry genotypes should be screened over multiple growing seasons in order to identify antioxidant-and phenolic-rich germplasm.

Flavonol glycoside composition and content in blueberry and blackberry extracts were determined using a high-performance liquid chromatographic (HPLC) separation method coupled with photodiode array (PDA) and mass spectrometric (MS) detection. The hydrophilic antioxidant capacities of crude and fractionated flavonol extracts were also determined by the oxygen radical-absorbing capacity (ORAC FL ) and photochemiluminescence (PCL) assays. Eight flavonols of quercetin and quercetin-sugar conjugates were identified in Kiowa blackberry, namely rutinoside, galactoside, methoxyhexoside, glucoside, pentoside, [6 -(3-hydroxy-3-methylglutaroyl)]-β-galactoside, glucosylpentoside and oxalylpentoside. Thirteen flavonols were detected in Ozarkblue blueberry. Of these, myricetin 3-hexoside and 12 quercetin-sugar conjugates, namely rutinoside, galactoside, methoxyhexoside, glucoside, pentoside, glucosylpentoside, caffeoylglucoside, oxalylpentoside, rhamnoside, dimethoxyrhamnoside, acetylgalactoside and acetylglucoside, were identified. In Bluecrop blueberry, two additional quercetin-sugar conjugates were identified, namely glucuronide and caffeoylgalactoside. Quercetin glycosides accounted for 75% of total flavonols in the blueberry genotypes. Total flavonol contents ranged from 99 to 150 mg kg −1 for blackberries and from 192 to 320 mg kg −1 for blueberries. Quenching of peroxyl and superoxide anion radicals by the flavonol fractions ranged from 1.5 to 2.3 mmol Trolox equivalents (TE) kg −1 and from 0.5 to 0.7 mmol TE kg −1 respectively for blackberries and from 2.9 to 5.2 mmol TE kg −1 and from 0.8 to 1.4 mmol TE kg −1 respectively for blueberries. The HPLC method allowed for complete separation and identification of flavonols commonly found in blackberries, and blueberries. Our results showed that blueberry and blackberry genotypes varied significantly in flavonol content and antioxidant capacity. Even though total flavonol content did not correlate well with antioxidant capacity, their ability to scavenge peroxyl and superoxide anion radicals was apparent.

Blackberry (Rubus L. subgenus Rubus Watson) improvement has made substantial progress with over 400 cultivars named originating from wild selections to many releases from breeding efforts. Public breeding has been ongoing for over 100 years. The result of these improvements is commercial production for processing and fresh markets in a number of countries. There has been excellent progress made in improving several very important traits. Fruit quality has been and continues to be a high priority in breeding, with selection for improved processing quality along with enhanced postharvest handling potential for fresh market expansion. Fruit size has been advanced and a range of berry sizes from small to very large exist among released cultivars. A number of plant characters have been addressed, with thornlessness becoming more common in recent introductions. Likewise, enhanced yield potential, improved disease resistance, and improved cane management characteristics have been achieved. More recently, primocane fruiting has been incorporated into blackberry, expanding production options. Breeding has been done using classical breeding methodology, crossing complementary parents and selecting improved progeny. Research using molecular methods has been limited in blackberry, and has not contributed substantially to cultivar improvement. Although breeding efforts in blackberry are more limited than the major berry crops, a continuous supply of new cultivars should result from ongoing programs. These, along with previous cultivar developments, will contribute to an ever-increasing number of cultivar options resulting in an increased of production of this increasingly popular berry crop.