• The Korean Journal of Food And Nutrition
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• v.34 no.4
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• pp.390-397
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• 2021

The purpose of this study was to investigate at how the quality of citron changed during storage as a result of the browning inhibitor treatment. In the browning inhibitor treatment, Vit.C, Vit.C+NaCl, Vit.C+NaCl+CD substances were used. As a result of investigating the browning degree, Vit.C+NaCl+CD showed the lowest value of 0.76 when stored for 12 weeks. The 𝚫E of the chromaticity value indicated that significant color change occurred when the value was high. As the Vit.C+NaCl+CD mixture showed the lowest value of 46.01 at 25℃, it was found that browning did not occur much compared to other treatments. The change in polyphenol oxidase (PPO) activity of citron increased as browning progressed. Among the browning inhibitor solutions, Vit.C+NaCl+CD solution showed the lowest value 118.8 u/g at 25℃ after 12 weeks. Based on these findings, it seems that CD mixing solution can be used as a citron browning inhibitor.

• 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.

• Journal of Animal Science and Technology
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• v.46 no.5
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• pp.849-858
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• 2004

This study was carried out to investigate the effects of addition of citron peel powder(0.3%, 0.6%, 0.9%) on the quality characteristics of emulsion-type sausages. The pH, color, TBARS, residual nitrite content and textural properties were evaluated. The pH values of sausage containing citron peel powder were significantly(P<0.05) lower compared to those for control. The CIE $L^*$ and $a^*$ values of sausage containing citron peel powder tended to similar to control, but the CIE $b^*$ values were significantly(p<0.05) higher in the sausage containing citron peel powder. The TBARS values of sausage containing 0.9% citron peel powder were significantly(P<0.05) lower than those of control at 20, 40 and 60 days of storage. The residual nitrite content of sausage containing citron peel powder were significantly(P<0.05) lower compared to control. The hardness values of sausage containing citron peel powder were significantly(P<0.05) higher than those of control, but the cohesiveness, springiness and gumminess were significantly(P<0.05) lower in the sausage containing citron peel powder.

• Korean journal of food and cookery science
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• v.6 no.1
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• pp.9-12
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• 1990

This study was carried out in order to investigate the physicochemical properties of isolated pectic substances from Citron, Satsuma mandarin, Marumero, and Natsudaidai. Among varieties, Citron had the highest value of isnoluble pectin and Marumero had the hightest ratio of soluble pection. The total pectin contents isolated by 2% Sodium hexameta-phosphate(SHMP) varied in the range of 1.85% ~ 2.63%. Anhydrogalacturonic acid(AUA) contents were 78.64%~89.14% and were lower than commercial pectin. Isolated pectin contained above 7% methoxyl content and above 50% esterification. The apparent molecular weight of commercial pectin and isolated pectin were 72,000 and 42,000~46,000 respectively. Esterification and ester methoxyl content were the lowest and apparent molecular weight was the highest in Satsuma mandarin. Citron's values were a little higher in esterification and ester methoxyl content and lower in apparent molecular weight than the others.

• Korean Journal of Food Science and Technology
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• v.28 no.6
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• pp.1071-1077
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• 1996

Quality changes in citron (Citrus junos) during storage were studied to investigate the efficiency, cooling properties and the washing and storage effects of hydrocooling method. As a result of plotting the nondimensionalized citron temperature versus cooling time, its cooling rate coefficient was shown to be $-0.012\;min^4{\sim}\;-0.017\;min^4\;(R^2=0.97{\sim}0.99)$ at center, and to be $-0.033\;min^4{\sim}\;0.075\;min^4\;(R^2=0.89{\sim}0.93)$ at surface. During storage, weight loss was more affected by storage temperature than by pretreatment condition and in reached $22{\sim}23%$ after 7 weeks at $15^{\circ}C\;and\;10{\sim}11%$ after 8 weeks at $5^{\circ}C$ in all samples. However, changes in moisture contents of hydrocooled citron were shown to be about $1{\sim}2%$ after 7 weeks while that of non-treated citron was about 3% after 1 week of storage at $5^{\circ}C$. And the change of pH, acidity and soluble solid content were not significantly different between each treatments during storage $5^{\circ}C\;and\;15^{\circ}C$. Changes in Hunter L, a, and b values of hydrocooled citron were lower than those of non-treated one as the storage time increased. The respiration rate of hydrocooled citron during storage at $15^{\circ}C$ was $103.63\;mg{\cdot}CO_2/kg{\cdot}hr$, which is about 50% of that of non-treated citron.

• 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 Food Science and Technology
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• v.30 no.1
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• pp.139-145
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• 1998

This study was performed to provide fundamental data on the optimum manufacture condition of oleoresin using citron peel. Oleoresin was extracted from freeze-dried or hot air dried citron peels using various solvents (hexane, ether, dichloromethane, acetone. and methanol), mixing ratio, extraction temperature, and time. As a result, optimum extraction conditions of oleoresin were: solvent mixing ratio 1:10 (w/v), extraction time 2 hours, and extraction temperature $60^{\circ}C$ when used methanol, and their dichloromethane 1:10 (w/v), 4 hours and $20^{\circ}C$, respectively. At optimum extraction conditions, the yield of oleoresin was shown that 35.79% at hot air drying samples, 32.04% at freeze-dried ones when extracted by methanol, but shown 5.86% and 6.16% when used dichloromethane respectively. The number of volatile components present in citron oleoresin were confirmed as thirty two in methnol extracion method and twenty nine in dichloromethane extraction method by GC and GC/MS, respectively. But, in the kinds and amounts of volatile flavor components, relatively greater numbers of volatiles were identified in freeze-dried sample extracted by dichloromethane compared with other methods. In freeze-dried sample extracted by dichloromethane, volatile components of citron oleoresin predominantly occupied by limonene and ${\gamma}-terpinene$ with about 85%. Other important compounds were shown hydrocarbons. such as ${\alpha}-pinene$, myrcene, terpinolene, ${\beta}-farnesene\;and,\;{\delta}-elemene$, and linalool as alcohols.

• 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.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.500-503
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• 1996

Volatile compounds were extracted from freeze-dried citron peel(Citrus junos) using supercritical CO2 under 4,000psi at 40$\beta$. Four fractions were obtained with consumption of CO2. Volatile compounds of extracts were analyzed by GC-MSD. Yield of vol atile compounds from citron peel was 0.11g/CO2($\ell$) and maximum yield was 8.812g/kg. Major volatile compounds of extracts were dl-limonene, Υ-terpinene, linalool, sabinene, $\beta$-myrcene, $\alpha$-pinene, $\beta$-farnesene, $\alpha$-terpineol and terpinolene. $\alpha$-Pinene, $\beta$-myrcene and dl-limonene in the fractions decreased gradually, while $\alpha$-terpineol and $\beta$-farnesene increased as the consumption of CO2 increased.

• Korean Journal of Human Ecology
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• v.4 no.1
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• pp.79-92
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• 2001

E. coli transformants EC3, EC4. and EC6. harboring citron oil degrading pathway genes, were co-cultured in M9 media with citron oil as a sole carbon source at 28$^{\circ}C$. Each co-culture(EC3+EC4, EC3+EC6, EC4+EC6 and EC3+EC4+EC6) showed three to four times higher cell growth than each transformant single culture. Microbial conversion products from the co-cultures were determined by GC-MS. Linalool. 4-terpineol and ${\alpha}$-terpineol were the major common products from co-cultures. Various minor products also were detected and important in flavor characteristics of cultures.