• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.187-194
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• 2021

This study aimed to optimize the preparation method of citron (Citrus junos Sieb.) beverages with hibiscus using response surface methodology (RSM). The experimental conditions were established using a central composite design with three independent variables as follows: ratios of citron (40~60%), citric acid (0.34~0.94%), and hibiscus (0.3~0.7%). The results indicate that an increase in the citron ratio contributed to increased sweetness and as the concentration of citron and hibiscus increased, the brightness of the citron beverage decreased and the yellowness increased. The citron ratio showed a significant correlation with the ABTS radical scavenging capacity. Among the 15 experimental groups, 4 representative samples showing statistical significance were selected, and sensory tests were performed, in comparison with commercially available products. As a result of the sensory test, four beverages prepared with the selected recipes showed higher preference than commercial beverages, and optimal recipe conditions were 40% citron, 0.34% citric acid, and 0.5% hibiscus.

• The Korean Journal of Food And Nutrition
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• v.33 no.4
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• pp.419-427
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• 2020

The purpose of this study was to investigate the qualitative changes of the citron by identifying the type of solution and addition of the solution to prevent the browning reaction of the citron in a way that inhibits the browning of the citron. The browning inhibitor solution was investigated using the individual and mixture, and the results of the degree of browning and chromaticity showed that vitamin C+NaCl+cyclodextrin (CD) had the lowest browning of 0.52. In chromaticity, the ΔE values indicate that the higher the value, the greater the change in color, and the lowest value of the vitamin C+NaCl+CD mixture was 47.0, indicating that there was minimal browning compared to other treatment. The active change of the polyphenol oxidase (PPO) in the citron increased enzyme activity as the browning progressed, and the vitamin C+NaCl+CD solution was the lowest at 68.40 μ/g among the anti-browning solution. Based on these research results, it seems that the CD mixing solution can be used as a citron browning inhibitor.

• Korean journal of food and cookery science
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• v.24 no.4
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• pp.460-465
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• 2008

The objective of this study was to evaluate the antioxidant properties and sensory qualities of citron peel tea, and to determine the optimum ratio of citron peel powder for its preparation. Yuza peel powders were prepared with citron peel tea at weight 2 and 3 g, respectively. Then, color values(L-value, redness, and yellowness), total phenol content, total antioxidant activity, DPPH radical scavenging activity, and sensory characteristics were measured in the tea samples. The pH of the citron peel tea decreased with increasing preparation temperature. And as the amount of citron peel powder increased, total phenol content, antioxidant capacity, and radical scavenging activity increased. The level of total phenolics in the tea had a higher correlation with total antioxidant capacity($r^2$ = 0.731). Depending on the level of added yuza powder, significant differences(p < 0.05) were shown for aroma, color, and overall acceptability however, there were no significant differences in sourness and bitterness.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.4
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• pp.496-502
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• 2005

The chemical properties and nitrite scavenging ability were analyzed which on a citron (Citrus junos) of 4 kinds purchased in different regions [Namhae (I, II), Tongyoung and Koheung] in Korea. Four kinds of organic acids were determined. Citric acid contents in flesh and peel of citron were $10.2\pm0.14\~17.7\pm0.17\;g/100g$. The organic acid content was the highest in citron purchased from Koheung. Total mineral content in citron was in a range of $2,844.3\~4,022.4$ mg/100 g, the potassium content was the highest in the range of $1,332.4\pm2.31\~2,308.5{\pm}3.25\;mg/l00g$. The major free amino acid from citron were proline, asparagine and glutamic acid. And the highest in peel of citron purchased from Tongyoung by 326.9 mg/100 g. However, the kinds and contents of chemical components in citron were somewhat different among various regions. The electron donating ability using DPPH method of citron juice was more than $80.0\%$ at the concentration of $0.1\~0.2\%$ and it was stronger by increased the juice concentration in the reaction mixture. SOD-like activity showed $10.2\pm0.50\~20.1\pm0.77\%$ at the concentration of $0.01\~0.2\%$. The nitrite scavenging ability was pH and sample concentration dependent. It was the highest at the pH 1.2 and more than $73\%$ in $0.1\~0.2\%$ citron juice. On the contrary in all concentration of added citron juice lower than $27\%$ at pH 4.2.

• Preventive Nutrition and Food Science
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• v.18 no.3
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• pp.196-202
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• 2013

Citron seed extracts (CSEs) were made using distilled water (CSEW), ethanol (CSEE), and n-hexane (CSEH), to measure the total polyphenol contents, DPPH and ABTS radical scavenging activities, and anti-complementary activity. The total polyphenol content was observed the highest in CSEE (188.71 ${\mu}g/mL$), and occurred in the following order: CSEE>CSEW (141.11 ${\mu}g/mL$)>CSEH (26.19 ${\mu}g/mL$) at 10 mg/mL. CSEE (63.56%) and CSEW (56.61%) showed significantly higher DPPH radical scavenging activities when compared with CSEH (28.57%). ABTS radical scavenging activities of CSEE (45.53%) and CSEW (40.02%) were also observed to be higher, whereas CSEH did not show ABTS radical scavenging activity. Anti-complementary activity of CSEE (26.85%) showed a greater activity than that of CSEW (7.84%) at 1,000 ${\mu}g/mL$. Limonin and nomilin contents had the highest values (1.882% and 2.089%) in CSEE, and with 0.327% and 0.139% in CSEW; however, CSEH showed relatively very low values at 0.061% and 0.026%, respectively. Among the CSEs tested, CSEE as a by-product from citron may provide an important source of dietary antioxidant compounds with rich polyphenol and limonoid contents, and immunopotentiating activity, including the complement activation factor.

• Journal of the East Asian Society of Dietary Life
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• v.7 no.3
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• pp.301-307
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• 1997

To enhance the utility value of citron, vinegars were made of citron juice, their properities were investigated, the results are as following. Optimum bacteria was Acetobacter sp. PA 97 for the citron vinegar fermentation, optimum temperature, initial acidity and alcohol concentration were 3$0^{\circ}C$, 1.5% and 8%, respectively. The lower citron juice was added, the more citric acid was produced, the acidity of sample added sub-nutrition source was higher than that of sample no added. In samples added citron juice of 10, 20 and 30%, and sub-nutrition source, total acidity were 5.42, 5.36 and 5.04%, pure acetic acid yields were 52.69, 45.25 and 35.10%, respectively. Remained alcohol of sample no added sub-nutrition source was more than that of added. In the sensory test, the most suitable concentration of citron juice for vinegar fermentation was 30%.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.636-639
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• 2003

Entercbacter agglomerans 6L was isolated from citron (Citrus junos) peel by using an enrichment culture containing (+)-limonene. It was able to metabolize limonene and grew well ($A_{600}$:4.5) on limonene as a sole carbon source. E. agglomernas 6L was highly resistant to limonene toxicity, and grew to 1.0 optical density ($A_{600}$) even at 5% (v/v) of limonene in Luria-Bertani media. ${\gamma}-Valerolactone$ and cryptone were detected as the major metabolic products of limonene by E. agglomerans 6L.

• 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.

• The Korean Journal of Food And Nutrition
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• v.17 no.2
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• pp.212-219
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• 2004

In this study, we compared that sensory characteristics and nutritional components of ice cream supplements with various levels(1, 2, 3％) raw and frozen citron juice. Vitamin C was not detected in frozen citron juice 1％ added group. The content of vitamin C was 4.7 mg/100g in raw citron juice 3％ added group. But it detected 1.0 mg/100g in 3％ frozen citron juice added group. Free sugars were detected sucrose, lactose and maltose. Those amounts of all samples were lower than control group and were lower goes to citron juice added ratio higher. Organic acids in ice creams were detected oxalic acid, malonic acid, malic acid and citric acid. The citric acid content was higher than other organic acid. Especially, citric acid content was the highest in raw citron juice 3％ added group (6.3 mg/100g). But it's content was low in all frozen citron juice added groups (0.5-0.6 mg/100g). Mineral contents of ice creams were highest in raw citron juice 3％ added group (3399.96 mg/100g). The results of sensory test, citron aroma and citron taste were the highest in raw citron juice 3％ added group. Overall acceptability was the highest in frozen citron juice 2％ added group.

• 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.