• Food Science and Preservation
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• v.3 no.1
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• pp.23-32
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• 1996

Total carotenoid contents, color values and spectrum characterization in the range of UV of fruit juice and organic acid and free sugar contents determined by HPLC were investigated on 10 varieties of Cheju citrus fruits. Carotenoid contents of juice were 0.47-9.20$\mu\textrm{g}$/ml which showed higher with Dangyooja while showed lowest content with Meiwa Kumquat. Lightness (L) of juice was highest in Meiwa Kumquat, and in the order of Sankyool, Navel orange and Hungjin. Redness(a) and yellowness(b) were in the order of Dangyooja, Natsudaidai, Sambokam and Kinkoji. The maximum absorption wavelengths if citrus Juices were variable at 269.5-285.5nm according to varieties and it was observed that were changed by mixing with Juices of other varieties. Major organic acids of citrus juice were citric and malic acid, and citric acid was 64.4-95.1% of total organic acids. Ascorbic acid was high in Navel orange, Sudachi and Dangyooja, and low in Meiwa Kumquat and Hungjin. Major free sugars were sucrose, glucose and fructose. Sucrose was 49.2-75.2% of total free sugars, and high in Sankyool and Meiwa Kumquat. Glucose and fructose were high in Meiwa Kumquat and Navel Orange.

• Horticultural Science & Technology
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• v.32 no.1
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• pp.1-9
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• 2014

This study investigated the effects of temperature on the shoot growth and flowering of potted kumquat [Fortunella margarita ( Lour.) Swingle] trees grown in subtropical conditions of I-Lan County in Taiwan. Temperature treatments included T 25-32, T 17-25, T 22, and T 18. The T 25-32 treatment trees were to the day/night temperatures of $25/18^{\circ}C$ for 2 weeks, followed by 28 weeks at $32/25^{\circ}C$. T 17-25 was exposed for 4 weeks to $17/10^{\circ}C$ followed by 26 weeks at $25/18^{\circ}C$. T 22 and T 18 were exposed at $22/18^{\circ}C$ and $18/13^{\circ}C$, respectively, for the entire duration of the experiment. Control trees were placed in a plastic greenhouse under conditions similar to the natural environment. The kumquat trees exposed to high-temperature environment of $32/25^{\circ}C$ showed more frequent and speedy sprouting of new buds, but induced the earlier termination of shoot elongation growth, resulting in decreased vegetative growth. The temperature treatments lower than $22^{\circ}C$ suppressed the new shoot production but increased the shoot growth period, resulting in increased shoot length and diameter. Temperatures higher than $25/18^{\circ}C$ readily induced flowering, with flowering being advanced under the higher temperature conditions such as $32/25^{\circ}C$. However, flowering was substantially inhibited under temperature conditions lower than $22/18^{\circ}C$, indicating the negative role of relatively lower temperatures on flowering of kumquat trees.

• Journal of Food Hygiene and Safety
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• v.17 no.4
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• pp.201-205
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• 2002

When it added to each designed diet groups such as control, nitrate rich, amine rich and nitrate-amine rich diet under simulated gastric conditions, effect of kumquat (Fortunella mararita) juice on formation of N-nitrosodimethylamine (NDMA) was studied. Inhibition on NDMA formation was the highest in the amine rich diet, as 69.4 $\pm$2.4%, when the juice of 10m1 added to its digestate. Phenolic portion of $C_{18}$ sep-pak cartridge in kumquat juice were separated into 20 kinds of a phenolic compounds using HPLC. These phenolic fractions such as faction no. 1, 2, 3, 4 and 5 inhibited from 3.0 $\pm$ 1.2% to 66.5 $\pm$2.0% NDMA formation in the reaction system which was mixture of nitrite and dimethylamine.

• Korean Journal of Food Science and Technology
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• v.24 no.5
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• pp.423-427
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• 1992

The volatile components were extracted from kumquat(Fortunella margarita) by simultaneous steam distillation-extraction method and fractionated on silica gel column. The total volatile oil was eluted off first by n-pentane and eluted again by diethyl ether. The total volatile oil and diethyl ether fraction were analyzed by GC and GC-MS. In the total volatile oil, 10 components were identified, of which major ones were limonene(96.5%, of total volatile oil), ${\beta}-pinene$(1.93%) and ${\alpha}-terpineol$(0.42%) and then the characteristic aroma of kumquat appeared to be due to limonene. On the other hand diethyl ether fraction, from which 46 components were identified, contained 9 alcohols, 22 terpenes and terpene alcohols, 7 aldehydes and ketones, 7 esters and 1 miscellaneous components. The major components were ${\alpha}-terpineol$(31.98% of diethyl ether fraction), ${\beta}-terpineol$(7.37%), geranyl acetate(9.69%) and p-menthadien-9-ol(4.12%).

• Food Science and Preservation
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• v.2 no.2
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• pp.259-268
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• 1995

Physico-chemical components which are closely related to processed products were investigated on 10 varieties of Cheju citrus fruits. Juice ratio of Hungjin was the highest, 49.2%, while Sankyool was the lowest, 4.2%, which showed great differences among varieties. Peel ratio of Dangyooja was the highest, 46.1%, while both Navel orange and Hungjin were relatively low. Soluble solid($^{\circ}$Brix) was relatively high In Sankyool, Meiwa Kumquat, Sambokam and Iyo. Acid content was the highest, 4.86% in sudachi and relatively high in Sankyool, Natsudaidai and Dangyooja. The $^{\circ}$Brix to acid content ratio was 13.9 in Meiwa Kumquat and more than 10 in Navel orange and Hungjin. Total sugar contents of Juice were 2.78∼10.94%, while reduced sugar contents were 1.63∼6.38% which showed higher in Meiwa Kumquat, Iyo and Navel Orange. Hesperidin and naringin, the sources of biiter taste and cloudness were low in Hungjin and Iyo. Soluble solid($^{\circ}$Brix) of citrus juice showed highest statistical relationship(r=0.907) with total sugar, and was highly significant at 1% level.

• Food Science and Preservation
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• v.24 no.3
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• pp.394-405
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• 2017

This study was conducted to confirm the usefulness of essential oil components in yuzu and kumquat cultivated in Korea for comparison with those in lemon and lime. The volatile flavor compounds in citrus fruits (yuzu, kumquat, lemon and lime) were extracted for 3 h with 100 mL redistilled n-pentane/diethylether (1:1, v/v) mixture, using a simultaneous steam distillation and extraction apparatus (SDE). The volatile flavor compositions of the samples were analyzed by gas chromatography-mass spectrometry (GC-MS). The aroma compounds analyzed were 104 (3,713.02 mg/kg) in yuzu, 87 (621.71 mg/kg) in kumquat 103 (3,024.69 mg/kg) in lemon and 106 (2,209.16 mg/kg) in lime. Limonene was a major volatile flavor compound in four citrus fruits. The peak area of limonene was 35.03% in yuzu, 63.82% in kumquat, 40.35% in lemon, and 25.06% in lime. In addition to limonene, the major volatile flavor compounds were ${\gamma}$-terpinene, linalool, ${\beta}$-myrcene, (E)-${\beta}$-farnesene, ${\alpha}$-pinene and ${\beta}$-pinene in yuzu, and ${\beta}$-myrcene, ${\alpha}$-pinene, (Z)-limonene oxide, (E)-limonene oxide, geranyl acetate and limonen-10-yl acetate in kumquat. Furthermore, ${\gamma}$-terpinene, ${\beta}$-pinene, ${\beta}$-myrcene, geranyl acetate, neryl acetate and (Z)-${\beta}$-bisabolene in lemon and ${\gamma}$-terpinene, ${\beta}$-pinene, (Z)-${\beta}$-bisabolene, neral, geranial and neryl acetate in lime were also detected. As a result, it was confirmed that the composition of volatile flavor compounds in four citrus fruits was different. Also, yuzu and kumquat are judged to be worthy of use alternatives for lemon and lime widely used in the fragrance industry.

• The Korean Journal of Community Living Science
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• v.16 no.1
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• pp.15-20
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• 2005

To identify and compare the nutritional composition of different kinds of citrus, three examples (Citrus fruit, Kumquat, and Hallabong) were taken from Jeju island in Korea at the same time and their nutritional compositions were measured using the Association of Official Analytical Chemists (AOAC) method. The proximate components (moisture, protein, fat, fiber, ash, and carbohydrates), mineral and vitamin contents were measured. The Nutrient composition revealed some significant differences among the Citrus. The Citrus fruit has more moisture and Fe content than those of the Kumquat. The Kumquat contained more ash, Ca, Na, Mg, Zn, Vitamin A, and B1 than the other Citrus specimens, while the Hallabong had the most protein and Fe. However, fiber, K, Vitamin B₂, C and niacin contents were not significantly different among the specimens. The results demonstrate that the three kinds of citrus used in this study have different nutritional compositions, but they can all be used as a good food for supplementation of K, vitamin A and C. We hope the nutritional analysis of Citrus specimens will be helpful in meeting the consumer's interest in these Citrus, and increase the export of our Citrus produce.

• Journal of the Korean Society of Food Science and Nutrition
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• v.23 no.2
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• pp.315-321
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• 1994

In order to prevent the postharvest decay and to promote the freshness retention of fruits and vegetables grapefruit seed extract(GFSE), natural microorganism control agent, was applied to the preservation of fresh fruits and vegetables. Freshfruits and vegetables treated with GFSE and stored in polyethylene film (0.1mm) at 1$0^{\circ}C$-15$^{\circ}C$ of natural low temperature low kept better qualities in color and texture than the GFSE -not- treated control. The treatment using GFSE ina 250ppm to 500ppm concentration seemed to be an effective one for the control of Botrytis cinerea isolated in red wine grapes. After 4 weeks of storage the firmness rate of cucumbers treated with the dilute GFSE was four times higher than that of non-treated ones. GFSE showed effective inhibitory action towards plant pathological bacteria and fungi which were involved in the decay of fruits and vegetables. Minimum inhibitory concentrations of GFSE towards them were in the range of 250ppm to 500ppm .Direct visualization of microbial cells and spores using electron microscopy showed microbial cells and fungal spores the function of which was destroyed by treating with the dilute solutions of GFSE. It was observed that GFSE would reduced disease damages and have bactericide & fungicide properties during the storage of such fruits and vegetables as egg plant, wild edible greens , kumquat, and kiwi fruit.

• The Plant Pathology Journal
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• v.15 no.6
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• pp.335-339
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• 1999

Citrus tristeza virus(CTV), an aphid-borne closterovirus, is one of the most destructive pathogens of citrus. It has caused rapid decline in growth, stem pitting and death in citrus trees. A reverse transcriptase polymerase chain reaction (RT-PCR) assay was developed for detection of CTV and investigation of the CTV infection status of citrus and its related cultivars in Cheju island. For RT-PCR based CTV detection, primers were designed to amplify 670bp of coat protein gene. A screening test for CTV in citrus cultivars was conducted from March to July in 1999. Seventy individual citrus trees representing 9 species of 3 genera were tested. The infection rates of CTV for leaves from the years or older trees of late maturing citrus varieties such as Yuzu (C. junos Sieb. ex Tanaka), Navel orange (C.sinensis Osbeck), Kiyomitanger (C. unshiu x C. sinensis), and Shiranuhi ((C. unshiu x C. sinensis) x C. reticulata) were 100%, 80%, 60%, and 60% respectively. The CTV infection rates in Early satsuma mandarins such as 'Miyagawa Early' Satsuma mandarins (C. unshiu Marc. var. Miyagawa) and 'Okitsu Early' Satsuma mandarins (C. unshiu Marc. var. Okitsu) were 100%, and 60%, respectively. CTV was not detected in Cheju native Dangyooja (C. unshiu Marc. var. Osbeck), Trifoliate orange (Poncirus trifoliata) and Kumquat (Fortunella margarita Swingle). In conclusion, RT-PCR assay can be successfully applied to the detection of CTV in citrus trees.

• Journal of the Korean Society of Food Culture
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• v.29 no.6
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• pp.659-667
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• 2014

Fruits are good sources of vitamins, minerals, fiber, and phytochemicals, which are known to reduce serum lipids, oxidative damage, and blood pressure as well as improve blood glucose control. The purpose of this study was to estimate nutrient quality indices of fruits by carrying out a critical analysis of pre-existing methods according to their nutritional compositions. Four methods were used to assess the nutrient indices of 26 fruits, which are frequently consumed by Koreans based on the fourth Korean National Health and Nutrition Examination Survey (2009). Naturally nutrient rich score (NNR), nutrient rich food (NRF), nutrient adequacy score (NAS), and nutrient density score (NDS) were used to calculate nutrient quality indices. The Korean Nutrition Society Food Composition database of fruits based on 100 g edible portions was used. The algorithm of each method included the mean percentage of daily values (Dietary Reference Intakes for Koreans, 2010) for particular nutrients based on consumption of 1,900 kcal/day. The relative score indicated that strawberries, kumquat, and lemon had high nutrient quality indices. In addition, mango, lemon, persimmon, strawberry, apricot, and tangerine fruits are rich in antioxidant nutrients such as ${\beta}$-carotene, vitamin C, vitamin E, and selenium. However, scores of nutrient quality indices did not imply that higher scores of particular fruits are superior. We suggest moderate seasonable consumption a variety of fruits. Our results can be used as a reference for consumers when they choose fruits.