• Korean Journal of Food Science and Technology
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• v.26 no.5
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• pp.552-556
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• 1994

It was aimed to study the chemical characteristics and volatile compounds of juices extracted by press (PE) and centrifugal extractors (CE). Citrons cut up cross direction were used as samples in PE. Proportion ratio of peel, flesh, and seed of citron were 43.9, 39.4 and 16.7%, respectively. Yield of juice increased with weight to 120g of citron fruit. pH, brix, pulp, oily materials, amino nitrogen and yield of juice extracted by CE were higher than those of juice by PE. Acidity and transmittance of juice extracted by PE were higher than those of juice by CE. Free sugars of citron juice were consisted of fructose, glucose and sucrose. Free sugar contents of juice by CE were twice as much as those of PE. Major volatile compounds of total steam distillation matters of citron juice extracted by PE were dl-limonene, ${\gamma}-terpinene\;{\beta}-farnesene$, sabinene, linalool, ${\beta}-myrcene$ and terpinolene, while those by CE were dl-limonene, ${\gamma}-terpinene$, sabinene, ${\beta}-myrcene,\;{\alpha}-pinene$, linalool and terpinolene. dl-Limonene and ${\gamma}-terpinene$ consisted of $73{\sim}83%$ of total volatile compounds. dl-Limonene of juice by CE increased about 6% that of juice by PE. ${\beta}-Farnesene$ were observed trace in juice by CE but presented in 7% in juice by PE. The results would suggested that chemical characteristics and volatile compounds of citron juice seemed to depend on extraction methods.

• Korean Journal of Food Science and Technology
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• v.26 no.6
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• pp.709-712
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• 1994

The volatile components of citron juice juice extracted by three methods, which were Rotary-crushing and screening method (method I), Pressing method (method II) and Belt pressing method (method III), were analyzed with GC and GC/MS. Juice extracted by method III had more components of flavor than those by methods I and II. Also, the contents of total volatile components in method III were about 1.36 and 1.59 times than those in methods I and II, respectively. Limonene in juice extracted by method III was predominantly occupied, amount of which was 76.87%. Other important components were terpene hydrocarbons, such as ${\gamma}-terpinene$, ${\alpha}-terpinene$ and so on.

• Applied Biological Chemistry
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• v.38 no.2
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• pp.141-146
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• 1995

Changes of physicochemical properties of citron juice prepared by two different extraction methods, rotary-crushing and belt-pressing method, were investigated during the storage at $5^{\circ}C$ and $-20^{\circ}C$. Temperature drop of citron juice extracted by belt-pressing method was faster than that of citron juice prepared by rotary-crushing method and its freezing point was $0.8{\sim}0.9^{\circ}C$. During the storage, pH of stored citron juice with rotary-crushing method was increased up to 3.5 after 6 months storage while that of citron juice extracted by belt-pressing method was not changed significantly during the same storage time. Acidity of rotary-crushed citron juice was reduced a little more than that of belt-pressed citron juice during the storage. However, changes of soluble solid content were influenced largely by the storage temperature than by the extraction method. Contents of formol nitrogen and vitamin C were reduced remarkably in all of stored citron juice and $92{\sim}82%$ of farmol nitrogen and $72{\sim}43%$ of vitamin C were remained after 6 months of storage. Among the changes of color value, L values were reduced in the whole stored citron juice and a and b value had a different change pattern respectively according to the extraction and storage temperature. Changes in the content of both amino acid and fatty acid compositions was also observed after same storage period. Especially, in the case of change of fatty acid composition, content of linoleic acid and linolenic acid were reduced after 6 months storage, while those of palmitic acid, stearic acid and oleic acid were increased.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.145-150
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• 1997

This study was performed to compare the changes of quality in citron(Citrus junos Sieb) juice between sampleII stored at 5$^{\circ}C$ for 1 year after extraction and sampleI made from raw citrons by the belt-pressing extraction method. Compared with sampleI, the soluble solid of sampleII was decreased more than 1$^{\circ}$brix, and the moisture increased 3%. The acidity reduced from 5.83 to 5.23 at the pH rose from 2.68 to 2.84. Although it decreased more than 50% in vitamin C and over 20~30% in amino acid, the changes of the other proximate components, amino nitrogen and free sugar content were very little at the range 0.1~1.0%. Volatile compounds in citron juices between sampleI and II were analyzed by GC and GC-MS. Sample I and II showed about 70 of volatile compounds. But only 13 compounds were identified by mass spectrometer. Major volatile compounds were aromatic compounds of limonene, terpinene, terpineol and terpinolene. Amounts of volatile compounds in citron juices depended on the storage period. The recovery of volatile compounds of citron juices, reduced 30~50% after storage for 1 year and the trace component disappeared during storage. The sensory characteristics including color, aroma, taste and overall acceptability and sugar recipe were not significantly.

• Korean Journal of Environmental Biology
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• v.21 no.1
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• pp.31-35
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• 2003

The effects of different extraction methods on quality of citron juices were investigated in terms of chemical composition and sensory evaluation. Extraction methods employed were press-filtration with 400 mesh sieve, centrifugation, and enzyme pretreatment using pectinase. Enzyme pretreatment method showed the highest yield of juice with 68%, while press-filtration method, the lowest yield of juice with 26.3%. The pH of the juices was relatively similar at 3.29～3.34. Filter-pressed juice showed the highest concentration of soluble solid at 6.0$^{\circ}$Brix, while the juice produced using centrifugation showed the lowest concentration at 4.5$^{\circ}$Brix. In all the juices, fructose was the main soluble sugar. Concentration of organic acid was the highest with the juice produced with centrifugation so that supplementation with higher amount with sugar was needed for overall acceptability.