• Food Science and Preservation
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• v.19 no.1
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• pp.87-94
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• 2012

This study was carried out to investigate the physicochemical characteristics of maturating and dried jujube. The moisture contents of the unripe and ripe jujube were found to be 84.66 and 66.45%, respectively, but that of the dried jujube was 31.48%. The crude-fat and crude-ash contents of the dried jujube were much higher than those of the maturing jujube. The carbohydrate contents of the unripe, ripe, and dried jujube were found to be 13.51, 27.94, and 61.70%, respectively, and the soluble-protein contents were 0.88, 1.73, and 3.71%. The reducing-sugar content of the dried jujube was 18.82%, higher than that of the ripe jujube. The sucrose contents of the unripe and ripe jujube were 10.15 and 16.66 g/100 g, respectively, and that of the dried jujube was 33.46 g/100 g. The major fatty acids that were found to compose jujube were palmitic, oleic, pamitoleic, linoleic, and linolenic acid. The myristoleic and arachidonic acid contents were higher in the dried jujube than in the ripe jujube, but the palmitoleic acid content was lower in the dried jujube than in the ripe jujube. The major minerals of jujube were found to be Ca, K, Mg, and P, and the total mineral contents of the unripe, ripe, and dried jujube in this study were 343.38, 584.94, and 331.56 mg/100 g, respectively. The polyphenol contents of the unripe, ripe, and dried jujube were 309.12, 248.80, and 23.34 mg/100 g, respectively, while the vitamin C contents were 610.04, 310.22, and 423.27 mg/100 g.

• Korean journal of food and cookery science
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• v.18 no.6
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• pp.670-676
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• 2002

Four different brands of commercial and a home-made jujube tea were analyzed for physicochemical properties (sugar content, acidity, color, viscosity, transparency, texture) and sensory characteristics by using 7-point scoring test from 18 experienced panel members. Also, the opinion of food and nutrition specialists on the commercial jujube teas were assessed using a questionnaire, which were hand-delivered to 530 subjects consisting of university students and faculties of Department of Food and Nutrition at 8 cities(Seoul, Incheon, Youngin. Taejon, Chungju, Taegu, Kwangiu, Pusan) in Korea and the complete data of 328 subjects were statistically analyzed using SPSS Program for Window. The questionnaire consisted of socio-demographics, frequency and occasion of purchasing, opinion of quality and improvement points, and sensory characteristics. Commercial jujube teas (3 different brand) were lower in sugar content, pH, transparency, color (Hunter L, a and b value), and viscosity than the home-made one, whereas only one brand was higher in viscosity and lower in transparency than home-made one. Also, overall preference for commercial jujube teas was significantly love. than that for home-made one (p＜0.05). Especially, the scores of overall preference for 3 commercial jujube teas (2.1-3.3) were much lower than that of home-made one (6.1). Points to be improved for commercial jujube teas were indicated as the amount of jujube (30.0%), taste (23.8%), sweetness (22.0%), and flavor (14.4%) in order. Sensory attributes showing positive correlations with overall preference of jujube tea were the taste(0.566), amount of jujube(0.449), and flavor(0.335).

• 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.

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2002.02a
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• pp.79-85
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• 2002

본 연구는 대추 수확기개발을 위한 기초연구로써 대추의 열매, 잎, 잎줄기의 물리적 역학적 특성을 조사.분석하였으며, 그 결과를 요약하면 다음과 같다. .대추 열매의 평균 장경, 경, 부피, 무게, 탈과력은 각각 32.02 mm, 23.9 mm, 10.0$\times$$10^{-6}$m$^3$, 5.2~12.8g, 5.7 N으로 나타났다. .대추무게가 증가하면 탈과력은 증가하고, F/W는 감소하는 경향을 나타났다. .대추나무가지의 평균 탄성계수는 7.01$\times$$10^{8}$ N/m$^2$였고, 가지의 굵기가 증가하면서 감소하였다. .대추나무가지의 평균 비틀림 강성은 5.2$\times$$10^{7}$ N/m$^2$으로 나타났으며, 가지의 굵기가 증가하면서 음의 지수 함수적으로 감소하는 경향을 나타냈으나, 데이터가 일정한 범위에 산재해 있어 가지의 굵기에 따른 강성계수변화 특성은 일정한 경향으로는 나타나지 않았다. .대추 잎줄기의 평균 무게, 잎수, 길이가 각각 0.7g, 6.6개, 12.2 cm로 나타났다. .대추 잎의 평균 잎면적, 무게, 탈리력은 각각 13 $cm^2$, 0.2g, 4.4 N으로 나타났다. .종말속도는 대추 열매의 무게가 증가하면서 증가하고, 대추잎의 무게, 면적이 증가할수록 감소하는 경향을 나타냈으며, 잎줄기의 종말속도는 잎줄기 무게 혹은 잎줄기에 매달린 잎의 수와는 거의 영향을 받지 않는 것으로 나타났으며, 잎줄기의 길이가 증가할수록 약간씩 증가하는 경향을 나타냈다.

• Food Science and Preservation
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• v.19 no.2
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• pp.243-248
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• 2012

The physicochemical properties and nutritional components of fermented black jujube (FBJ) were compared with those of dried jujube (DJ) to improve their utilization as food materials. The moisture contents and brix of the DJ and FBJ were 22.6% and 6.07 brix, and 10.36% and 7.23 brix, respectively. Their L values were 34.78 and 31.82, and the a and b values of DJ were higher than those of FBJ. DJ had a lower water activity level (0.75) than FBJ (0.45), but FBJ had a higher amount of reducing sugar and soluble protein than DJ. The major free sugars in the two types of jujube were fructose and glucose, and their potassium content was highest (about 90%) among minerals. Their unsaturated fatty acid contents were 51.0% and 59.83%, respectively, and the major fatty acids myristoleic acid, palmitic acid, and palmitoleic aid were detected in them.

• Food Science and Preservation
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• v.20 no.1
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• pp.52-61
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• 2013

This study was conducted not only to investigate the effects of rate of addition of dried jujube to Yakju (0, 0.5, 1.0, 1.5, 2.0 percent) but also to examine the quality changes in jujube Yakju during its storage (for 75 days at $35^{\circ}C$). The results showed no significant differences in pH, total acidity, soluble solids, and anthocyanin and alcohol contents of the Yakju right after its fermentation. With the increase in the amount of jujube that was added, the lightness of the jujube Yakju changed from 93 to 94, its redness decreased, and its yellowness significantly increased. The jujube Yakju that was fermented with 1.5-percent dried jujube had high sensory evaluation (selection rate) scores for color, flavor, taste and overall acceptability. It had no significant changes in pH and total acidity during its storage after its heat treatment. Its soluble solids contents tended to decrease with its heat treatment and to increase in its storage period. With respect to its color changes during its storage, the higher the ratio of the jujube that was added, the longer the storage period was, the lightness (L) and redness (a) decreased and the yellowness (b) increased. The polyphenol contents depended on the rate of addition of the dried jujube, but were not affected by the heat treatment and storage period. The organic acids in jujube Yakju were citric acid, succinic acid, lactic acid, malic acid and acetic acid.

• 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.

• Applied Biological Chemistry
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• v.40 no.1
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• pp.43-47
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• 1997

The weight ratio of the seed in jujube averaged to 19.1%. The chemical components of dried pitted-jujube were moisture 20.4%, protein 5.3%, fat 1.3%, ash 2.7%, fiber 4.4% and nitrogen-free extract 65.9%. Alcohol insoluble solid content of dried pitted-jujube was 17.4%, in which ammonium oxalate-soluble pectin was 3.7%, water-soluble pectin 3.0%, hydrochloric acid-soluble pectin 1.0%, and sodium hydroxide-soluble pectin 1.0%. Jujube contained sucrose, glucose and fructose as free sugar. The sugars of dried pitted-jujube was composed of sucrose 48.1%, fructose 18.7%, and glucose 11.3%. Drying experiments of pitted-jujube and unpitted-jujube were carried out. Moisture content and brix of dried pitted-jujube were reached at that of dried unpitted-jujube(11%, 78 brix in 48 hours of dry) in 11 hours of drying. And this means that dried pitted-jujube dried 4 times faster than dried unpitted-jujube. The extracts of dried pitted-jujube and dried unpitted-jujube were examinet according to the amount of water added and the extraction time. The brix of dried pitted-jujube extract for 30 min is similar to that of dried unpitted-jujube extract for 150 min. The brix of the extracts did not increase after 150 min extraction. As to the color of extract, 'L' value was higher in dried unpitted-be, while 'a' and 'b' values were higher in dried pitted-jujube.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.10
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• pp.1346-1355
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• 2012

This study was carried out to investigate the characteristics of black jujube and Zizyphus jujube extracts during lactic acid fermentation. Both extracts were fermented using Lactobacillus fermentum YL-3. As a result, viable cell number rapidly increased until 24 hours, after which it gradually decreased. Before lactic acid fermentation, the $IC_{50}$ of black jujube, which was 0.014 mg/mL, was lower than that of Zizyphus jujube. Further, black jujube showed stronger antioxidant activity (374.21 mg AA eq/g) than Zizyphus jujube. Contents of total polyphenolics in both extracts were 15.46 mg/g and 13.61 mg/g, respectively, whereas contents of total flavonoids were 374.21 ${\mu}g/g$ and 64.25 ${\mu}g/g$. After lactic acid fermentation, there was no significant increase in DPPH or ABTS free radical scavenging activity. Total polyphenolic content of Zizyphus jujube decreased to 12.39 mg/g upon fermentation, whereas flavonoid content significantly increased to 291.58 ${\mu}g/g$. Further, polyphenolic and flavonoid contents of black jujube increased from 15.46 mg/g to 17.46 mg/g and from 374.21 ${\mu}g/g$ to 1,135.29 ${\mu}g/g$, respectively. These results demonstrate that 9-Times Steamed and Dried increased functional components. Especially, lactic acid fermented black jujube showed remarkably high antioxidant activity. These results confirm the potential use of lactic acid fermented black jujube as a valuable resource for the development of functional foods.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.4
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• pp.642-647
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• 2002

This study aimed to find optimum addition of jujube powder to glutinous rice in the preparation of daechu injeolmi (rice cake). The daechu injeolmi added with 10% jujube powder gave the highest moisture content of 52.9% among treatments. Higher amount of jujube powder up to 14% resulted in lower 'L' and higher 'a' values of the cake. Hardness of the cake showed the lowest value for the 10% jujbe-added cake during the storage of 24 hours, while it was so for 14% jujube-added cake after 36 hour storage. Little change was observed with time in the cohesiveness for the cake added with jujube powder in more than in the 8% level. 10% addition of the jujube powder was found to be the best recipe based on the sensory qualities of softness, chewiness, moistness and overall acceptability, which were also well correlated with physical properties.