• Journal of the Korean Society of Food Science and Nutrition
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• v.43 no.3
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• pp.471-476
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• 2014

We developed a method for improving the antioxidant activities of blueberry (Vaccinium ashei) extracts through an ultra high-pressure extraction process. Blueberries were subjected to water extraction at $60^{\circ}C$ and 300 MPa for 5 min (High Pressure Extraction, HPE5) and 15 min (HPE15). Extraction yields obtained by ultra high-pressure extraction process were 18.48, and 19.89%, respectively. Total polyphenol contents were estimated to be 28.3, and 28.9 mg/g, whereas flavonoid contents were measured as 5.9 and 6.0 mg/g, respectively. Generally, HPE resulted in higher yields than the conventional extraction process. Further, HPE15 showed 53.84% DPPH radical scavenging activity (EDA, %) at $1,000{\mu}g/mL$. Reducing power of HPE15 showed its highest activity of 0.21. In general, antioxidant activities of blueberry increased by HPE. Therefore, HPE of blueberry resulted in higher antioxidant activity than conventional water extraction. These results demonstrate obvious advantages in terms of higher efficiency, shorter extraction time, and lower energy costs.

• Food Science and Preservation
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• v.19 no.4
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• pp.604-610
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• 2012

The nutritional composition and in vitro anti-oxidant activities of blueberry (Vaccinium ashei) leaf extract were investigated to examine their physiological characteristics. Calcium was the most abundant mineral. The principal free sugars were glucose, sucrose, maltose, and fructose. The amino acids were mainly composed of glutamic acid and aspartic acid. The fatty acids consisted mainly of 40.94% saturated fatty acid and 54.35% unsaturated fatty acid. In addition, the 112.64 mg% of vitamin C was analyzed as a natural anti-oxidant. Based on the bioactivity-guided isolation principle, the resulting ethanolic extracts from the blueberry leaf were divided into several fractions of n-hexane, chloroform, ethyl acetate, and water. The ethyl acetate fraction showed the greatest total phenolic content. The total phenolics and flavonoid were 50.51 mg of GAE /g and 13.09 mg%, respectively. The ABTS-radical-scavenging activity of the ethyl acetate fraction was 97.53% at a concentration of 500 ${\mu}g/mL$. The ferric-reducing anti-oxidant power of the ethyl acetate fraction increased in a dose-dependent manner. The results suggest that the ethyl acetate fraction of the blueberry leaf extract has good in vitro anti-oxidant activities and excellent nourishment, and can thus be useful food resources.

• Culinary science and hospitality research
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• v.20 no.1
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• pp.55-64
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• 2014

This study was performed to determine the effects of drying methods on the quality and physiological activities of blueberry. Blueberries(Vaccinium ashei) were dried by hot-air ($60^{\circ}C$), cyclic low pressure ($50^{\circ}C$), and freeze drying methods. They contained high properties of carbohydrates(68.48~80.00%), crude protein(1.63~5.41%), crude fat(0.58~1.25%), and ash(0.71~1.11%) regardless of the drying methods. There were no differences in pH according to the drying methods. Browning index increased as the drying temperature increased. The L, a values of the freeze-dried sample were higher than those of the other dried samples, whereas the b value of the cyclic low pressure dried sample was higher than that of the other samples. The free sugar contents of the hot-air sample were higher than those of the other samples. Vitamin C content of the freeze dried sample was higher than that of either the hot-air or cyclic low pressure dried sample. The contents of total polyphenols and anthocyanins were higher in the freeze dried sample. The DPPH radical scavenging activity of freeze drying sample was higher than that of either the hot-air or cyclic low pressure dried sample. The result indicated that there were no differences in product quality depending on the freeze-drying and cyclic low pressure drying methods.

• Food Science and Preservation
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• v.25 no.1
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• pp.107-116
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• 2018

The aim of this study is to investigate the antioxidant and intracellular anti-inflammatory efficacy of blueberry leaf extracted with hot water (BLW), 70% ethanol (BLE), and 70% acetone (BLA) in RAW 264.7 macrophages. In order to evaluate the anti-inflammatory effect of blueberry leaf extracts, RAW 264.7 macrophages were stimulated with lipopolysaccharide (LPS) to induce the production of inflammation-related factors, which were measure by Western blotting and real-time PCR methods. i-NOS, COX-2 protein, and mRNA expression showed concentration-dependent decrease. The decreases in the mRNA expression levels of interleukin-$1{\beta}$ (IL-$1{\beta}$), interleukin-6 (IL-6), tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$), and prostaglandin $E_2$ ($PGE_2$) were concentration-dependent. Further, the antioxidant effects of blueberry leaf on total polyphenol contents, electron donating ability and $ABTS^+$ radical scavenging activity were evaluated. The total polyphenol contents of BLW, BLE, and BLA were $217.04{\pm}2.98$, $156.72{\pm}3.90$, and $182.88{\pm}3.02mg\;TAE/g$, respectively, while the electron donating abilities at $1,000{\mu}g/mL$ of BLW, BLE, and BLA were 81.7, 79.6, and 79.3%, respectively. The $ABTS^+$ radical scavenging activity was fond to be concentration dependent. The nitric oxide (NO) production inhibition activities at $50{\mu}g/mL$ of BLW, BLE, and BLA were 35.1, 42.4 and 42.7%, respectively. In conclusion, the antioxidant and anti-inflammatory test results indicate that blueberry leaf extracts (BLW, BLE, and BLA) can be used as potential anti-inflammatory agents.

• Korean Journal of Environmental Agriculture
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• v.36 no.3
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• pp.161-168
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• 2017

BACKGROUND: Rabbiteye blueberry(Vaccinium ashei Reade) has low nutrient uptake efficiency due to its shallow and fibrous root system without root hairs. This study was carried out to establish an efficient nutrient application standard by investigating the effect of nitrogen fertigation on the growth and fruit characteristics of rabbiteye blueberry. METHODS AND RESULTS: 'Brightwell' rabbiteye blueberry was treated with 0, 50, 100 and 200% nitrogen fertigation of recommended fertilizer application (6, 9 and 14 g/bush in the first, second and third years, respectively). The results showed that leaf nitrogen content significantly correlated with the fruit weight and fruit yield. However, canopy area, dry weight, sugar and anthocyanin contents did not correlate significantly with the leaf nitrogen content. The leaf and stem dry weights of 'Brightwell' rabbiteye blueberry during the third year of planting were the highest with 50% nitrogen fertigation (leaf dry weight=723.7 g/bush; stem dry weight=890.7 g/bush). Maximum fruit yield of 'Brightwell' rabbiteye blueberry (12.9 kg/bush) was observed during the third year of planting with 50% nitrogen fertigation and this was about 70% greater than the treatment that received no nitrogen fertigation. The fruit yields of 'Brightwell' rabbiteye blueberry during the third year of planting treated with 100 and 200% nitrogen fertigation were 11.0 and 11.5 kg/bush, and these were 17 and 12%lower than the 50% nitrogen fertigation treatment, respectively. Further, the efficiency of nitrogen utilization was the highest (90%) with 50% nitrogen fertigation and lowest (18%) with 200% nitrogen fertigation. CONCLUSION: The results of this study suggests that fertigation with 50% of the recommended fertilizer could be most effective for enhancing the growth and nitrogen use efficiency of rabbiteye blueberry.

• Korean Journal of Environmental Agriculture
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• v.39 no.4
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• pp.360-367
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• 2020

BACKGROUND: The productivity and quality of blueberry (Vaccinium ashei Reade) greatly depend on the number of fruits in a plant. Especially, fruit set more than appropriate number negatively affects productivity and marketability due to the increased number of small fruits and delayed harvest time. This study was conducted to investigate proper timing and concentration for applying chemical blossom thinners such as ammonium thiosulfate (ATS) and UREA. METHODS AND RESULTS: ATS at 1.25% and 1.50%, and UREA at 6% and 8% were applied in four developmental stages, bud swell, pink bud, full bloom and petal fall. Fruit thinning rate was calculated based on the number of fruits harvested divided by that of flowers before applying blossom thinners. Ratios of leaf to flower and leaf to fruit were calculated based on the number of fully developed leaves in 25 days after full blossom divided by that of flowers or fruits, respectively. Chemical injury of leaves was investigated by calculating the number of leaves with chemical injury divided by the total number of leaves. Fruit thinning rates were 48% and 66% for UREA treatments at 6% and 8%, respectively, and 49% and 62% for ATS treatments at 1.25% and 1.50%, respectively, in the full bloom stage. In the petal fall stage, fruit thinning rates were 18% and 24% for UREA treatments at 6% and 8%, respectively, and 49% and 35% for ATS treatments at 1.25% and 1.50%, respectively. Leaf to fruit ratio (L/FR) increased by 109% and 188% compared to leaf to flower ratio in ATS treatments at 1.25% and 1.50%, respectively, and L/FR increased 93 and 196% in UREA treatments at 6% and 8%, respectively, in the full bloom stage. In the petal fall stage, leaf to fruit ratio increased by 60% to 100% in ATS treatments, but did not significantly differ from the control in UREA treatments. Fruit harvest was delayed in all treatments of all developmental stages except for 1.5% ATS and 6% UREA treatments at the petal fall stage, whose fruit harvest was two or three days faster than the control. CONCLUSION: The application of ATS and UREA for blossom thinning should be in the petal fall and full bloom stages for early and late harvest, respectively. Considering chemical injury, integrated harvesting and fruit size, however, it is appropriate to apply ATS at 1.5% in the petal fall stage to increase fruit productivity and quality in blueberry.

• Korean Journal of Environmental Agriculture
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• v.33 no.4
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• pp.327-333
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• 2014

BACKGROUND: Rabbiteye blueberry(Vaccinium ashei) is one of the most widely grown blueberry types in the world, together with Northern and Southern highbush blueberry(Vaccinium corymbosum). Rabbiteye blueberry have higher soil adaptability and fruit productivity but less cold tolerance to low temperature than highbush blueberry. The objective of this study is to investigate freezing tolerance of floral buds and establish a cultivation zone for rabbiteye blueberry cultivars. METHODS AND RESULTS: Bearing branches which have similar thickness and same number of floral buds were collected in the early January at the blueberry germplasm preservation plot located in Namhae Sub-station, National Institute of Horticultural and Herbal Science in Gyeongsangnamdo. Cold response of bearing branches were investigated by electrolyte leakage and freezing tolerance of floral buds were determined by ovary browning ratio of 50%($LT_{50}$). Cultivation zone was established based on mean annual extreme minimum temperature for 30 years, from 1981 to 2010. The electrolyte leakage of bearing branches in rabbiteye blueberry increased as temperature decreased and was lowest in 'Brightwell' but highest in 'Bluegem' when they were kept in $-5^{\circ}C$. Besides, the electrolyte leakage increased in 'Brightblue', 'Brightwell', 'Climax', 'Delite', 'Gardenblue', 'Southland' and 'Woodard' in $-20^{\circ}C$. Freezing tolerance($LT_{50}$) was lowest in 'Bluegem' and 'Homebell'($-13.3^{\circ}C$), and highest in 'Tifblue'($-25^{\circ}C$) among different rabbiteye blueberry cultivars. $LT_{50}$ of 'Southland' was from -15.0 to $-16.7^{\circ}C$, that of 'Delite', 'Brightwell',' Austin' and 'Climax' was $-18.3^{\circ}C$, and that of 'Bluebelle', 'Woodard' and 'Powderblue' was $-20^{\circ}C$. CONCLUSION: This study indicate that The hardiness zones of rabbiteye blueberry were classified into Six cultivation zones and cultivation zones of most cultivars were the south of Jeollanam-do and Gyeongdangnam-do, except for 'Tifblue.'