• Korean Journal of Food Science and Technology
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• v.19 no.4
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• pp.346-354
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• 1987

The voflatile fraction from Korean mandarin (Citrus reticula) and valencia orange essence oil were analyzed by capillary gas chromatography and the separated components were identified from their retention time and mass pectrum. The essence oil were extracted with methylene chloride after steam distillation. The major volatile constituents of mandarin and sweet orange was limonene which accounted for 68% of total volatiles in mandarin and 87% in sweet orange. The 31 components identified from mandarin include 11 hydrocarbones, 1 ester, 10 alcohols, 4 aldehydes, 5 miscellaneous. The following 37 components were identified in sweet orange; 12 hydrocarbones, 1 ester, 11 alcohols, 8 aldehydes, 5 misecellaneous. Mandarin contained more octanal, ${\alpha}-terpinene$, terpineol, styrene, dcitronellol, citronellal, citral and farnesol while orange included more sweet orange, myrcene, ${\beta}-pinene$, linallol, decanol, ${\beta}-copaene$, elemene, ${\beta}-cadinene$, valencene.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.658-665
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• 1995

Low yield of a thermostable pectinesterase(TSPE) from citrus fruits has made its detailed study extremely tedious and difficult; therefore, maximizing TSPE extraction is desirable. It is assumed that TSPE is bound to the cell components via ionic linkage and covalent bonds. Therefore, in this study, variations in extraction time, pH, NaCl concentration and commercial enzyme preparations were used to increase the yield of TSPE from Valencia orange. The largest recovery of TSPE, obtained by heating extracted pectinesterase(PE) at $70^{\circ}C\;for\;5{\sim}10$ minute, was achieved using actate buffer(pH 4.14) with 1 M NaCl and 0.2% $Cytolase^{TM}$ 104(a mixture of cellulase, hemicellulase and pectinase; Genecor, Inc). The two aquous phase partitioning with 5.0% Triton X-114 could be used as a tool for separation of thermolabile pectinesterase(TLPE) and TSPE from crude PE. Also, water extraction and $0{\sim}0.3$ ammonium sulfate fractionation could be used for removing non-pectinesterase protein.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.974-981
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• 1997

A combined treatment of high hydrostatic pressure and carbonation was used to inactivate pectinesterase (PE) and sterilize microorganisms in Valencia orange juice without major changes in its nutritive components. Quality characteristics of Valencia orange juice, such as microorganisms, PE activity, vitamin C content and color, were evaluated after it was treated with pressure, carbonation-and-pressure, and heat. Quality changes during storage at $4^{\circ}C$ and $30^{\circ}C$ after the treatments were also investigated. Pressurized orange juice (pressurized at 600 MPa for 10 min at $20^{\circ}C$) showed 7.0% residual PE activity, while the carbonated-and-pressurized orange juice (207 $kPa-CO_2$ gas pressure, pressurized at 600 MPa for 10 min at $20^{\circ}C$) showed 0%. Pressurization at 400 MPa or higher decreased the population of microorganisms in the orange juice to less than 10 CFU/mL. Carbonated-and-pressurized orange juice showed slight decrease in vitamin C content when stored at both $4^{\circ}C\;and\;30^{\circ}C$. While heat-treated ($90^{\circ}C$ for 60 sec) orange juice showed 75% decrease in vitamin C content when stored at $30^{\circ}C$. L value (lightness) and b value (yellowness) of carbonated-and-pressurized orange juice were higher than those of heat-treated orange juice when they were stored at $4^{\circ}C$ for 30 days.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.666-672
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• 1995

This study was carried out to characterize thermolabile pectinesterase (TLPE) and thermostable pectinesterase (TSPE) separated from crude PE of Valencia orange in order to investigate the preventive measures of cloudy juice clarification. The TLPE was observed to be mixture of several isoenzymes with the same molecular weight of 36 KD (37.5 KD) but different isoelectric point of pH 8.4, 8.7, 8.9, 9.8 and ${\geq}10$ which were unstable at $70^{\circ}C$, and the TSPE also was found to be mixture of two or three isoenzymes with the same molecular weight of 53 KD (50 KD) but different isoelectric point of pH 8.7, 9.2 and ${\geq}10$ which had slightly different stability from one another at $70^{\circ}C$. The TLPE and the TSPE had the optimum reaction pH of 7.0 and $7.0{\sim}8.5,\;appK_{M}$ of 1.1 and 1.7 mg/ml, appVmax of 0.53 and $1.01\;{\mu}mol/min/{\mu}g$, and the turnover number of 19.000 and 54,000 mol/mol/min toward Kodak pectin, respectively. The TSPE had higher storage stabiblity and cloud loss effect on orange juice than the TLPE. Above all, the crude PE was most effective on orange juice cloud loss among the PEs used.

• Food Science and Preservation
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• v.21 no.3
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• pp.365-372
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• 2014

Imported Valencia oranges were evaluated to determine the relationship between the fruit size and its quality. The orange size was classified into three groups on a commercial basis: small ($140{\sim}160g/113{\pm}5$ fruit/box), medium ($190{\sim}220g/88{\pm}5$ fruit/box), and large ($250{\sim}280g/72{\pm}5$ fruit/box). The physicochemical and sensory properties were analyzed to evaluate the orange quality. No significant difference in the peel thickness and flesh ratio was detected across the fruit sizes. The juice yield of the medium-sized orange and the TSS/TA ratios of the medium-sized and large oranges showed the highest value, respectively (p<0.05). The large orange had the highest vitamin C content, which was positively correlated with both its DPPH and ABTS radical scavenging abilities (p<0.05). In the sensory evaluation of the fruits and their juice, the scores for sourness and overall preference were significantly higher in the medium-sized and large oranges than in the small ones. The total soluble solids, total acidity, TSS/TA ratio, and reducing sugar content were significantly related to the sensory properties. Finally, the quality and sensory properties were considered superior in the medium-sized and lager Valencia oranges. Further studies on the effects of the variety and origin of Valencia oranges on their quality and sensory properties are required.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.673-679
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• 1995

Pectinesterase(PE) has been definitively established as the causative agent for clarification of citrus juice and gelation of frozen concentrates. This enzyme is present in multiple forms in citrus fruit. Although representing a minor fraction of the total PE activity, thermostable pectinesterase(TSPE) accounts for the severe time/temperature processing treatment required to inactivate PE. This study was undertaken to separate and purify thermolabile pectinesterase(TLPE) and TSPE from the crude PE extracts of Valencia orange rag-pulp powder. The approach taken was to carry out the three kind of chromatographies of CM-Sephadex C-50, Phenyl Sepharose CL-4B and CM-Biogel A to the unheated crude PE or the heated crude PE. All of them used could increase the purity of PEs and, specially, Phenyl Sepharose CL-4B chromatography could separate crude PE as the mixture of PEs into two forms of TLPE and TSPE. The purified TLPE had specific activity of 1,005 units/mg, yield of 13.6% and purification of 35 fold, while the TSPE separated from the unheated crude PE showed specific activity of 3,115 units/mg, yield of 1.5% and purification of 100.5 fold, and another TSPE from the heated crude PE was found to be specific activity of 1,803 units/mg, yield of 15.4% and purification of 140 fold.

• Food Science and Preservation
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• v.23 no.7
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• pp.1012-1017
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• 2016

This study was conducted to investigate total flavonoid content, flavonoid composition, and free radical scavenging effects of by-products from five orange cultivars during the period September 2015 to February 2016. Total flavonoid content was highest in peel extracts from immature fruit harvested in September. Total flavonoid contents of all cultivars mostly decreased while ripening. Among the five cultivars, total flavonoid content was highest in Hamlin sweet orange (21.66 mg/g), followed by Sanguinello blood orange (20.39 mg/g), Shamouti orange (18.49 mg/g), Tarocco blood orange (18.46 mg/g), and Olinda Valencia orange (17.07 mg/g). With regard to flavonoid composition, all cultivar materials had high levels of narirutin and hesperidin, but naringin and neohesperidin were not detected in any of the materials. Nobiletin, as polymethoxyflavone, was detected within a$23{\sim}40{\mu}g/mL$ range in the immature fruit of all cultivars. Among all cultivars, antioxidant activities were higher in peel extracts than in pulp extracts. DPPH radical scavenging activities of peel extracts ranged from 40% to 58% while the ABTS radical scavenging activity range was 90~94%. The results indicate that orange, by-products, especially peel of immature orange fruit, could have application as natural materials with antioxidative effects.

• Food Science and Preservation
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• v.22 no.5
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• pp.629-635
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• 2015

The effect of temperature on the quality and characteristics of Valencia oranges were studied during storage at low ($4^{\circ}C$, LT) and room ($20^{\circ}C$, RT) temperature. Hardness decreased beginning on the 10th day of storage, regardless of temperature, and showed a more considerable reduction in the peel than the flesh. The total soluble solids (TSS) and titratable acidity (TA) decreased from the 30th day at LT and the 10th day at RT, but the TSS/TA ratio did not change during storage. The vitamin C content decreased from the 20th day at LT and the 10th day at RT, and the total phenol content decreased from the 10th day of storage. In a sensory evaluation, the scores changed less for taste than for color and flavor during storage. The quality of Valencia oranges under two different temperatures was similar on the 30th day at LT and on the 10th day at RT. The TSS (r = 0.9453) and vitamin C content (r = 0.9104) were highly related to sensory properties. These results suggested that TSS and vitamin C are potential indicators of quality for the selection of Valencia oranges during storage.

• Food Science and Preservation
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• v.12 no.4
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• pp.361-366
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• 2005

An electronic nose equipped with metal oxide sensor(MOS) was used for investigating the quality of reconstitute orange juice added different recoverable oil(cold pressed valencia oil) contents during 21 days of storage at $4^{\circ}C$. Quality changes in orange juice was described in terms of the sensitivity(${\Delta}R_{gas}/R_{air}$) of the sensors. Principal component analysis(PCA) was carried out using data obtained from twelve metal oxide sensors. The flavor of orange juice contained with the different recoverable oil contents($0.01\%{\sim}0.05\%$) was separated in PCA plot, in which the first principal component score was correlated with the content of recoverable oil. As storage periods prolonged, no significantly different sensitivity score of orange juice was observed in electronic nose. The content of recoverable oil in orange juice was reduced rapidly within 14 days, and then the decreasing ratio was slow on the next 7 days during storage at $4^{\circ}C$. The sensory score for overall and orange flavor of orange juice added $0.03\%$ recoverable oil was decreased during the 14 days and then rapidly dropped next 7 days of storage at $4^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.13 no.1
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• pp.86-96
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• 1984

In order to provide basic data for food processors and to improve eating habits and healthy diets, four primary tastes and hot taste threshold of Koreans, physio-chemical properties of foods and food preference were investigated. The results of this study were as follows; 1. The recognition threshold concentration of four primary tastes was 0.016 % of salt, 0.245${\sim}$0.249 % of sweet, 0.004${\sim}$0.008 % of sour and 0.008${\sim}$0.012 % of bitter. Threshold concentration of hot taste was 170,000${\sim}$600,000 Scoville Heat Unit(S.H.U.) 2. The most acceptable tastes were 0.3 % saltiness in 0.375 % broth(at $60^{\circ}C$), 6 % sweetness in 2 % instant coffee(at $60^{\circ}C$) and 19.3 sugar-acid ratio(16.8 brix/0.8736 % citric acid) in 100 % valencia orange juice(at $20^{\circ}C$). 3. The salt concentrations of soup were 1.127 % in average. S. H. U. (scale of hot taste) of soybean sprout soup and spinach bean paste soup ranged between 12,500 and 47,500 equivalent to oleoresin capsicum content of 1.990${\sim}$5.911 (mg %). 4. 'Jigae' (Korean style stew) was the most favorable food and it was revealed that the father influences the formation of his children's eating habits.