• Korean Journal of Environmental Agriculture
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• v.40 no.2
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• pp.73-82
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• 2021

BACKGROUND: The successful management of jujube trees depends on maintaining a balance between reproductive and vegetative growth. In general, heading cuts of trunk stimulate rather vegetative growth, but could decrease flower initiation. This study was conducted to establish a heading-back pruning severities at planting in the one year old 'Daeneung' jujube whip nursery tree by investigating vegetative growth and fruit yield. METHODS AND RESULTS: The heading back pruning severity was assigned as 5 different ranges as follow: one bud (TR-10, heading back pruning was 10 cm above the ground), three buds (TR-30), five buds (TR-50), seven buds (TR-70), and nine buds (TR-90) were left of scion. The number of buds on whip trunk was correlated to the central leader length and increment of trunk cross-sectional area, negatively, and to the tree height and canopy volume, positively. The yields in the TR-50 treatment were higher about 2 times than other treatments. The fruit diameter was not significantly different among the treatments. CONCLUSION: These results indicated that the optimum location of heading-back pruning in one year old 'Daeneung' jujube tree was 50 cm above the ground as evaluated by the balance of reproductive and vegetative growth.

• Horticultural Science & Technology
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• v.33 no.3
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• pp.396-402
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• 2015

This study identified a new male-sterile germplasm of Chinese jujube, named male-sterile No. 2 (JMS2), and achieved controlled hybridization using that germplasm as the female parent. The anthers of JMS2 before flower bud opening became shrunken, dingy yellow and much smaller than normal ones, and they changed to brown after anthesis. No pollen was observed in anthers of JMS2 and its male-sterile trait remained stable over different years. A total of 1,642 fruits were obtained from ten intra- and interspecific cross combinations via controlled hybridization from 2008 to 2012 using JMS2 as the female parent. Of those, 27.3% produced seeds, on average (0-72.6%). The rate of fruit with seed (RFS) was significantly different between cross combinations or years. Compared to other cross combinations, the RFS in the combination of JMS2 ${\times}$ 'Xingguang' (a Chinese jujube cultivar with high resistance to jujube witches' broom disease) and JMS2 ${\times}$ 'Xing16' (a sour jujube genotype) remained high in different years and reached means of 48.7 and 58.1%, respectively. Finally, 150 plantlets were regenerated from immature embryos, and 51 of them were randomly selected and identified to be authentic hybrids using amplified fragment length polymorphism (AFLP) markers. This is the first report of hybrids obtained from a cross between Chinese jujube and sour jujube.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.4830-4836
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• 2013

This research was launched as an attempt to help create a new value-added product called "Green Jujube Chip." To accomplish the objectives, consumers value by attributes of Green Jujube Chip should be estimated. We used Choice Experiment for analysis, which we used to arrive at pricing of specialty jujube chips based on the conditional logit model. As a result, MWTP were estimated at 1333 Won/unit for Mid-size Company Product, 1752 Won/unit for Large Company Product, 1703 Won/unit for University Affiliation, 350 Won/unit for packing unit, 548 Won/unit for rating the raw fruit, 1,322 Won/unit for HACCP, and 1,166 Won/unit for ISO22000. The consumer's WTP for Green Juju Chip, associated with the university-brand recognition, was higher than a product produced by a mid-sized company but lower than a product by a large company. Given how the consumers regard the university-brand product as a specialty item, it is necessary to create value-added products that meet such high expectation. Therefore, we recommend the producers to acquire HACCP Food Safety Certification and the value-added product has used the highest quality raw fruit.

• Korean Journal of Food Science and Technology
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• v.44 no.6
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• pp.779-784
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• 2012

Characteristic chemical compositions of jujube wine using different preparation methods including fermentation were investigated. Fermentation for jujube wine started using whole fruit (JW1), seed-removed fruit (JW2) and whole fruit heated at $100^{\circ}C$ for 2 h and then extracted (JW3). The free amino acids and flavors were analyzed quantitatively by HPLC and GC-MS. A total of 18 amino acids were identified in all samples. The amount of total free amino acids was detected from 141-210 ppm (JW1), 147-342 ppm (JW2), and 336-362 ppm (JW3). Large amounts of proline, aspartate, glutamate, arginine and alanine were detected in jujube wine. Thirteen kinds of volatile compounds including six alcoholic compounds (ethyl alcohol, iso-butyl alcohol, n-butyl alcohol, iso-amyl alcohol, n-amyl alcohol, and phenethyl alcohol), four ester (ethyl acetate, hexyl acetate, ethyl caprylate, and phenethyl acetate) and three aldehydes (diethylacetal, furfural, and benzaldehyde) were detected. Ethyl alcohol (30.50-33.95% peak area), benzaldehyde (2.55-15.97% ratio), furfural (0.07-15.28% ratio), iso-amyl alcohol (1.04-14.73% ratio), and phenethyl acetal (0.78-9.28% ratio) were abundant in jujube wine.

• Korean Journal of Agricultural Science
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• v.31 no.2
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• pp.115-122
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• 2004

Physical and mechanical properties of fruits of jujube (Zizyphus jujuba Miller), leaves, secondary branches, and leafy stems were measured and analyzed. The physical dimensions of the fruits were measured and the detachment force of the fruit and leafy stems was measured. The detachment force of the jujube fruits increased and the force-to-weight ratio of the jujube fruits decreased as the weight of the jujube fruit increased. The weight of the leafy stems, number of leaves attached to the leafy stems, length of the leafy stems, diameter of the stem side of the leafy stems, diameter of the leafy stem end was average of 0.7g, 6.6ea, 12.2cm, 4.5mm, and 2.7mm, respectively. The major and minor axis of the jujube leaves, area of leaves, weight of the leaves, and detachment force of the leaves was average of 5.7cm, 3.3cm, $12.98cm^2$, 0.20g, and 4.39N, respectively. The terminal velocity of the jujube fruits increased as the weight of the fruits increased. The terminal velocity of the leafy stems, however, did not show a relationship with the weight of the leafy stems and the number of leaves attached to the leafy stem. The terminal velocity, however, slightly increased as the length of the leafy stems increased.

• Journal of Korean Society of Forest Science
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• v.102 no.1
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• pp.59-65
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• 2013

The jujube is an important fruit tree species in Korea. Traditionally, classifications of jujube cultivars have been based on morphological characters; however, morphological identification can be problematic because morphological traits are affected by environmental conditions. Therefore, DNA markers are now being used for the rapid and accurate identification of plant species. Inter-simple sequence repeat (I-SSR) is one of the best DNA-based molecular marker techniques, which is useful for studying genetic relations and for the identification of closely related cultivars. In this study, 5 Korean jujube trees and 1 jujube tree imported from China were analyzed for 16 I-SSR primers. Amplification of the genomic DNA of jujube cultivars by using I-SSR analysis generated 100 bands, with an average of 6.25 bands per primer, of which 45 bands (45%) were polymorphic. The number of amplified fragments with I-SSR primers ranged from 2 to 13. The percentage of polymorphism ranged from 10% to 100%. I-SSR finger printing profiles showed that 'Boeun jujube' and 'Daeri jujube' had characteristic DNA patterns, indicating unequivocal cultivar identification at molecular level. According to the results of clustering analysis, the genetic similarity coefficient ranged from 0.68 to 0.92. 'Boeun jujube' and 'Daeri jujube' were divided into independent groups, and 'Bokjo jujube', 'Geumseong jujube', 'Wolchul jujube', and 'Mudeung jujube' were placed in the same group. Therefore, I-SSR markers are suitable for the discrimination of 'Boeun jujube' and 'Daeri jujube' cultivars.

• Journal of Korean Society of Forest Science
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• v.111 no.4
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• pp.548-556
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• 2022

In this study, basic data were obtained to determine the optimal cultivation method to achieve stable fruiting and yield increase in "Cheonhwang" jujube trees. Accordingly, thefructification, fruit characteristics, and yield according to tree age were analyzed. The mean (and range of) tree height, crown area, stem diameter near the root, clear stem length, number of main branches, and distance between main branches were 235.6 (217.4-253.8) cm, 3.5 (3.1-4.1) m², 5.5 (4.0-7.1) cm, 70.6 (66.2-72.7) cm, 9.7 (8.6-10.5), and 10.4 (7.9-14.2) cm, respectively. Correlationanalysis results indicated that tree age was positively correlated with crown area, stem diameter near the root, and clear stem length but not with the number of main branches. The mean number (and range) of fruit per fruit-bearing mother shoot and tree were 18.3 (16.7-18.3) and 170.7 (157.9-178.3), respectively. Tree age was not significantlycorrelated with fruiting characteristics (i.e., the numbers of fruit-bearing mother shoots per main branch, fruit-bearing shoots per fruit-bearing mother shoot, fruit per fruit-bearing shoot, and fruit per tree). Given that the shape of jujube trees is constantly managed according to the growing area and greenhouse type, the tree growth characteristics were more affected by tree management techniques than by tree age. The mean (and range of) fruit weight, fruit hardness, and soluble solid content were 28.6 (27.7-30.3) g, 29.4 (28.5-30.4) N, and 20.4 (19.3-21.0) °brix, respectively, and these fruit characteristics were not significantly correlated with tree age.The average yield per tree of the 'Cheonhwang' jujube cultivar was 4.9 (4.8-5.0) kg, which was not significantly correlated with tree age.

• Food Science and Preservation
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• v.19 no.6
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• pp.901-908
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• 2012

This study was conducted to analyze the antioxidant activities of fermented black jujube and to compare these with those of dried jujube, for the development of functional materials. The antioxidative activities of dried jujube and fermented black jujube extracts were analyzed by electron-donating ability (EDA) using 1,1-diphenyl-2-picryl hydrazyl (DPPH), superoxide-dismutase-(SOD)-like activity by pyrogallol, nitrite-scavenging ability, and xanthin oxidase. The yield of the fermented black jujube extracts was higher than that of the dried jujube extracts, and that of the ethanol extracts was higher than that of the hot-water extracts. The total phenol contents of the hot-water extracts from fermented black jujube were higher. The EDA values of the hot-water and ethanol extracts from fermented black jujube and dried jujube increased with an increase in extract concentration, and were about 85% in a $1000{\mu}g/mL$ extract concentration. The SOD-like activity increased with an increase in extract concentration. The SOD-like activity of the hot-water extract from fermented black jujube was higher than that of the other extracts. The nitrite-scavenging ability at pH 1.2 of the hot-water extracts from dried jujube was higher than that of the other extracts. The xanthine oxidase inhibitory activities of the hot-water and ethanol extracts from fermented black jujube were higher than those of the other extracts, and increased along with the concentrations of the extracts.

• The Korean Journal of Food And Nutrition
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• v.23 no.3
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• pp.332-341
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• 2010

The chemical composition characteristics of jujube wine using different preparation methods including extraction in -soju (25%) and fermentation were investigated. The jujube wine was prepared by soaking in soju using- whole fruit(WJ-S1) or seed-removed fruit(WJ-S2). Fermentations of the jujube wine were started by using whole fruit(WJ-F1), seed-removed fruit(WJ-F2) or extracts of whole fruit(WJ-F3) after adding 24% sucrose. The pH of all samples decreased from a range of 4.92~5.42 at the start time to 3.66~4.97 after 100 days. The treatment WJ-F3 showed the lowest pH among all treatments. Total acid content was 0.67~1.01% at the initial stage and then changed to 0.51~0.88% after 100 days. Total sugar and reducing sugar contents were 1.20~13.8% and 0.50~4.45% at initial stage and then changed to 1.53~4.52% and 1.75~3.82% after 100 days respectively. These sugars decreased during the preparation and fermentation of the jujube wine. The amounts of free sugars including fructose, glucose, and sucrose ranged from 1.53~4.52% and treatment WJ-F3 showed the highest amount(1.95~13.64%) compared the other treatment. Glucose level were high in treatment WJ-S1 and WJ-S2, and fructose was increased in treatments WJ-F1, WJ-F2, and WJ-F3 after 60 days. Amino nitrogen content was 0.02~0.11% after 20 days and 0.07~0.14% after 40 days respectively. Solid content was 2.68~7.76% at the initial fermentation stage and changed to 4.81~9.73% after 100 days. Hunter color(L values) were 88.45~96.74 at the initial stage and then changed to 92.62~100.45 after 100 days. Preference tests a significant difference between the two types (extraction and fermentation) of jujube wine. And treatment WJ-S2 received the highest preference scores among the all treatments.

• Food Science and Preservation
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• v.5 no.4
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• pp.342-345
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• 1998

This study was investigated to the structure of cell wall during maturation for the research of softening of jujube fruits. Cell was hardly combined with each other untill turning stage, but middle lamella of cell wall was splited at mature stage and was observed splited cell. The middle lamella of cell wall was not observed at green mature stage, but was observed at turning stage. Cell wall was degraded at mature stage. It was observed mitochondria, endoplasmic reticulum et. at in jujube fruit of green mature stage, but cytoplasm and organelle was attached on cell wall as vacuole was grown up after turning stage.