• Journal of Biosystems Engineering
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• v.31 no.6 s.119
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• pp.500-505
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• 2006

Jujube is one of korean most favorite fruits. Harvesting operations of the jujube farming, however, completely depend on hand labor. Especially, collecting operation requires about three times of hand labor compared with separate operation by impacting or shaking of twigs in the hand-harvesting system of jujube fruits. Consequently, jujube farmers sincerely demand the mechanization of the collecting operation of jujube fruits in the harvesting operation. A new collecting system was designed and constructed five parts-collecting pad, guide ring system, sorting system, frame with driving system, and handle with operation levers, which performed collecting operation of jujube fruits without missing fruits in five part functions, however, an extra future more deliberate study would need how to handle conveniently the collecting pad of the prototype in the narrow space of row of the jujube farm.

• Food Science and Preservation
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• v.5 no.4
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• pp.346-349
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• 1998

This study was investigated to changes of texture, color and chemical properties in jujube fruits which dried by sun and hot air instrument. Weight and moisture contents were the lowest in jujube fruits dried by sun thin those of others. The ratio of water uptake was the highest in jujube fruits dried by hot air drying than those of others. The hardness and rate of rotting of dried jujube fruits were the highest in sun (Dying than those of others. The browning of jujube fruits dried by sun was higher than that of jujube fruits dried by other methods. Ash content was the highest in sun dried fruits than those of others, and content of vitamin C was the lowest in nm dried fruits than those of others.

• Journal of Biosystems Engineering
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• v.27 no.4
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• pp.283-292
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• 2002

Mechanical and physical properties of various parts of jujube (Zizyphus jojoba Miller) such as fruits, leaves, secondary branches, and leafy stems were measured and analyzed. The physical dimensions of the fruits were measured using a digital caliper, and the detachment force of the fruit and leafy stems was measured using a force gauge. The physical characteristics of the secondary branches such as the modulus of elasticity and the torsional rigidity were tested using a universal testing machine (UTM). The physical characteristics of leafy stems such as length and weight were also measured using a digital caliper and a digital scale, respectively. The detachment force of leafy stems and the area of the leaf also measured. The terminal velocities of the jujube fruits, leaves, and leafy stems were measured using a custom made terminal velocity experiment system. Diameter of the major and minor axis of the jujube fruit, weight of the fruit, and detachment force of the fruit stem was average of 32.02 mm, 23.92 mm. 10.0 ${\times}$ 10$\^$6/ ㎥, 8.99 g, and 5.43 N. respectively. The detachment forces of the jujube fruits increased and the force-to-weight ratio of the jujube fruits decreased as the weight of the jujube fruits increased. The modulus of elasticity of the secondary branches of the jujube was average of 7.01 ${\times}$ 10$\^$8/ N/㎡ and decreased as diameter of the secondary branches increased. The average torsional rigidity of the secondary jujube branches was 5.2 ${\times}$ 10$\^$-/ N/㎡, and the torsional rigidity decreased as the secondary branch diameter increased. The distribution of the torsional rigidity data associated with the diameter of the branches, however. widely scattered and it was difficult to find any relationship between the diameter of the branches and the torsional rigidity of tile branches. The weight of the leafy stems, number of loaves attached to the leafy stems, diameter of the stem side of the leafy stems, diameter of the leafy stem end was average or 0.7 g, 6.6 ea, 12.2 cm, 4.5 mm, and 2.7 mm, respectively. The major and minor axis of the .jujube loaves, area of leaves, weight of the leaves. and detachment force of the leaves was average of 5.7 cm, 3.3 cm, 12.98 cm$^2$, 0.20 g, and 4.39 N, 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 the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.827-830
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• 1997

Sensory evaluation method was used to develop a type jujube tea the organoleptic properties were evaluated with regard to the optimum sugar content, clarity, drinking temperature and fruit pulp content of the jujube tea. Clarified jujube tea extracted from 25% by weight of dry jujube fruits and 75% water was preferred to those from 15%, 20% and 30% jujube fruites although those from 20% and 30% were not significantly different at 5%level. In spite of the average acceptability score of cloudy jujube tea with 5% of added fruit pulp was not significantly different from that of clarified one, the more fruit pulp in the tea products the worse its acceptability. Cold jujube tea was preferred to warm and hot ones, but these were not significantly different.

• The Korean Journal of Food And Nutrition
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• v.31 no.5
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• pp.696-702
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• 2018

This study investigated the quality characteristics of jujube wines produced from various fruits (Campbell Early, aronia, apply). Before the preparation of jujube wine, jujube juice was extracted using hot water ($100^{\circ}C$, 2 hr). Different blends of jujube wines were produced by blending jujube juice with various fruits using Saccharomyces cerevisiae. After 18 days of fermentation, the alcohol content of jujube wines ranged between 11.5~12.7%. The pH of the wine ranged from 3.31 to 3.53 and the total acid content from 0.47 to 0.68%. The hue value of jujube wines ranged from 0.88 to 2.21 and the color intensity ranged from 0.93 to 6.29. The brightness of jujube wines ranged from 32.35 to 92.47, the redness from 0.85 to 59.05, and the yellowness from 17.35 to 51.02. By combining aronia with jujube juice, a significant increase in the total polyphenol content and the antioxidant activity (the DPPH radical scavenging activity) of the wine was observed. The total polyphenol content (401.77 mg%) and the antioxidant activity (76.29%) were the highest in the jujube wine blended with aronia. The total anthocyanin content of jujube wines ranged from 81.66 to 135.98 mg% and the tannic acid content from 42.48 to 316.36 mg%. Based on the results of the present study, we suggest that jujube wine produced by blending jujube juice with aronia had excellent quality as well as quality characteristics of the wine.

• Korean Journal of Agricultural Science
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• v.45 no.3
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• pp.365-378
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• 2018

Anthracnose caused by Colletotrichum gloeosporioides, which is one of the major diseases of red dates, causes severe damages in jujube (Zizyphus jujuba Miller) production in Korea. This study was done to evaluate the inhibition of anthracnose occurrence and pathogen growth by the treatment of environment-friendly materials such as a Bordeaux mixture and loess-sulfur mixture and by defense-response signaling in jujube. The in vitro test of the environment-friendly materials and signaling molecules that were routinely applied did not exhibit any antifungal activities against the pathogen for jujube anthracnose. The Bordeaux mixture and loess-sulfur mixture at a two-fold concentration showed inhibition zones that were 16.0 and 20.3 mm in diameter, respectively. In the pathogen inoculation test with detached jujube tree leaves, while treatment with the environment-friendly materials diluted by half showed no inhibition of lesion development, they did show inhibition of lesion development when they were routinely applied to the leaves. In detached jujube fruits inoculated with the pathogen, better suppressive effects by the treatment of the environment-friendly materials were seen in the fruits at a young stage rather than in the ripening stage. The in vivo test with jujube trees in pots showed that the treatment of salicylic acid (1 mM) resulted in the best suppressive effects against lesion development. The results suggest that it is possible to manage the incidence of anthracnose by the treatment of environment-friendly materials such as the Bordeaux and loess-sulfur mixtures and signaling chemicals such as ethephon, hydrogen peroxide, methyl jasmonate, and salicylic acid in jujube trees and fruits. Consequently, these findings suggest that environment-friendly materials and defense response signaling molecules could be used as suitable candidates for sustainable agrochemicals to manage anthracnose in jujube production.

• Food Science and Preservation
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• v.2 no.1
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• pp.185-193
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• 1995

This paper was investigated the changes of the cell wall components, enzyme activities during ripening of jujuba fruits for elucidating the softening metabolism of jujuba fruits. Firmness were decreased during ripening. Moisture content did not show any notable cahanges until ripening stage but they decreased a little In overripe jujuba fruits. Polygalacturonase activities were not detected at nature green stage and $\beta$-galactosidase activities were until turning stage. But polygalacturonase activities in ripening and overripening were 51.31 and 100.72 units/100g-fr, wt. respectively. $\beta$-galactosidase activities were 16.05 and 182.55units/100g-fr. wt. in the same stages. The content of water-soluble protein was increased in overripening. Stage the contents of cell wall and alcohol-insoluble material were. decraesed during maturation, but water-soluble material was increased. The pectin and alkali-soluble hemicellulose were increased until ripening stage, but decreased in overripe jujube fruits. The total pectin and insoluble pectin during ripening, but decreased in overripe jujuba fruits.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.6
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• pp.452-457
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• 2013

To obtain the useful data related to optimum nutrient management technique for pesticides-free jujube cultivation, nutrient contents of jujube leaves and fruits and the selected chemical properties of jujube orchard soils were investigated at 9 different orchards with pesticides-free cultivation in Boeun, Chungbuk, Korea. Soil and jujube leaf samples were collected from the different orchards in July and October, and jujube fruit samples were taken in October, 2012. Soil available $P_2O_5$ contents in the optimum level for jujube cultivation were 11% and 33% of total samples in July and October, respectively, but 56% of total samples was higher than the optimum level in both July and October. Exchangeable K and Ca ion contents were 44% and 67% of total samples, respectively, in both July and October, whereas exchangeable Mg ion content was 100% and 56% of total samples in July and October, respectively. Nutrient contents in jujube leaves were higher than those in fresh fruits. In addition, total nitrate, potassium and magnesium contents in the jujube leaves were higher in the samples collected in July than in October.

• Food Science and Preservation
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• v.17 no.5
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• pp.712-719
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• 2010

This study was carries out to analyzed the antioxidant activities and xanthine oxidase inhibitory effects of extracts from jujube to provide basic data for the development of functional materials. Antioxidative activities of extracts from jujube were analyzed by electron donating ability (EDA) using 1,1-diphenyl-2-picryl hydrazyl (DPPH), superoxide dismutase (SOD)-like activity by pyrogallol and nitrite scavenging ability. Extract yields from jujube fruits were 11.55% for unripe fruits, and about twice that value when ripe fruit extracts were prepared. The yields of hot-water and ethanol extracts was 55.67 and 65.95% in dried fruits, respectively. Total phenol contents were higher in unripe fruit extracts. The EDA values of hot-water and ethanol extracts from jujube fruits were increased by increase of extract concentration, and were about 90% in 10.0 mg/mL of extract concentration. The SOD-like activity was increased by the increase of extract concentrations. The SOD-like activity of the hot-water extract from unripe fruits was higher than that of other extracts. The SOD-like activity of ethanol extracts was 39.92% at 10 mg/ml of extract concentration from unripe fruits. The nitrite scavenging ability was about 50% in 1.0 mg/ml of extract concentration at pH 1.2, and that of extracts from unripe fruits was higher than that of other extracts. The xanthine oxidase inhibitory activities of hot-water and ethanol extracts from unripe fruits were higher than those of other extracts, were increased by concentration of extracts.

• Food Science and Preservation
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• v.17 no.1
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• pp.42-49
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• 2010

This study was developed a multi-step process of functional jungkwa preparation from jujube fruits to prepare a new processed food, and investigated on the quality of jujube jungkwa. The weight of jujube fruits notably increased during the second processing, compared with jungkwa prepared from dried jujube fruits using an osmosis drying treatment. The weight of jungkwa produced in the second processing step was less than those in the first step. The Hunter values (L, a, b) of dried jujube fruits after the first processing were less than those of control jujube fruits. The L value did not change after the second processing of jujube jungkwa, but the a and b values were markedly decreased. However, the Hunter values did not change during the third processing step. The moisture content of dried jujube fruit, and dried fruit treated by supplementary drying (DDJF) was 37.74 and 35.93%, respectively, and that of dried fruit treated by osmosis drying was 40.42%. The moisture content of dried jujube fruit after the second processing decreased by 2-10%, and by 4-10% after the third processing. The reabsorption ratio of jujube jungkwa after the second processing was 16.93%, and that of jungkwa produced from osmosis-dried fruit 24.81%. The strength and hardness of dried jujube fruit treated with supplementary drying (DDJF) were higher, at 3 and 2, respectively, compared to the values of dried jujube fruit. The rheology of jujube fruit and jungkwa did not change during the second processing. The color, glossiness, acceptability of appearance, flavor, and overall acceptability of dried jujube fruit treated by osmosis drying as the second processing step were somewhat higher than those of fruit processed by other methods. The scores for appearance, flavor, chewiness, after taste, and overall acceptability of dried fruits treated with supplementary drying as the third processing step were somewhat greater than those of fruit prepared by other means. Accordingly, we have developed a process for preparation of jungkwa from dried jujube fruit treated by supplementary drying and osmosis drying as the second and third processing steps.