• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.5
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• pp.831-837
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• 1997

Response surface methodology(RSM) was applied in roasting processes of Polygonatum odoratum roots in order to monitor Hunter color parameters and to optimize organoleptic properties of the tea. In roasting processing based on the central composite design with variations in roasting temperature (110~19$0^{\circ}C$) and roasting time(15~75min), coefficients of determinations($R^{2}$) of the models were above 0.9827(p<0.01) in Hunter color parameters and above 0.7748 in organoleptic properties. Hunter color L and $\Delta$E values of the powdered samples decreased with the roasting processes, whereas Hunter color a and b values increased up to around 59 min at 136$^{\circ}C$ and thereafter showed a decreased tendency. Organoleptic qualities on color, taste and aroma of Polygonatum odoratum tea were improved along with roasting processes, thereby estimating the optimum roasting conditions by RSM for the maximized qualities of organoleptic properties as a range from 127$^{\circ}C$ to 135$^{\circ}C$ and from 60min to 66 min. Hunter color a value(redness) was found to generate a similar response surface to that of organoleptic properties, showing the possibility of quality index in roasting processes of Polygonatum odoratum roots.

• Korean Journal of Food Science and Technology
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• v.17 no.6
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• pp.426-430
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• 1985

The effects of temperature on the visual color deterioration of Lithospermi radix were investigated under steady conditions of various pH and temperature. The changes of Hunter L, a, b, and ${\Delta}E$ values related to the color deterioration were sharply increased above $50^{\circ}C$ and the deteriorations were expressed linear relationships with the temperature above $60^{\circ}C$. Linear regression coefficients of Hunter L, a, b values decreased with an increase of heat treatment time, whereas the color difference was increased. The linear regression coefficients of Hunter L, a, b, ${\Delta}E$ values in 66.7% ethanol extract solution of Lithospermi radix for 1 hr were -0.3696, -0.4124, -0.2279, and 0.5983, respectively. Inear regression coefficients in color difference (${\Delta}E$) could be calculated from the coefficients in Hunter L, a, b values. The low pH treatment of extract from pH 6.07 to pH 1.35 led to decrease of Hunter a value and a little increase of Hunter L, b values, but the high pH treatment above pH 6.07 decreased all Hunter values. Particularly, the visual color of the extract of Lithospermiradix was appeared to be faborable at pH 4.0-6.5, which was a bright red color.

• Journal of the Korean Society of Food Science and Nutrition
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• v.31 no.2
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• pp.355-360
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• 2002

Effect of additive on color reversion of green tea extract, whose undesirable color had been removed by irradiation, was studied during storage. Hunter color L-vague of irradiated sample was significantly higher than that of nonirradiated control. The color of green tea extract with butylated hydroxyanisole (BHA) did not differ from that of the control but the green tea extract with ascorbic acid had higher L-value than the control during the whole storage (p<0.05), However, the sample irradiated at 20 kGy showed a faster color reversion than the sample with 5 or 10 kGy of irradiation. Hunter color a-values were decreased by irradiation and the sample with ascorbic acid showed the lowest. The result of Hunter color b-value was also similar to that of Hunter color a-value, indicating that when the irradiation technology is used for color improvement of green tea extract, the ascorbic acid can be added to minimize color reversion of the extract during delivery or storage.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.3
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• pp.466-470
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• 2001

Response surface methodology was used for monitoring extraction conditions, based on quality properties of old pumpkin extracts. Hunter's color L value of extracts was maximized at 101℃, 2.6 hr and decreased gradually after maximum point. The polynomial equation for Hunter's color L value showed 10% of significance level and 0.8799 of R². Hunter's color a value was minimized at 117℃, 3.9 hr and R² of polynomial equation was 0.9852 within 1% significance level. Hunter's color b value and ΔE value increased as the extracting temperature and time increased. Extraction yield of old pumpkin was maximized at 110℃, 4 hr and increased in proportional to the extracting temperature and time, but decreased after 113℃ and 2 hr. Viscosity of pumpkin extracts were maximized at 120℃, nearly 3 hr. R² of polynomial equations for yield, viscosity and sugar content were 0.9532, 0.9812 and 0.8869, respectively. Optimum ranges of extraction conditions for quality properties of old pumpkin were 102∼109℃, 2.5∼3.5 hr, respectively. Predicted values at the optimum extraction condition agreed with experimental values.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.47-52
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• 1999

Comparative effects of phosphine fumigation and gamma irradiation were evaluated on the qualities of white ginseng prepacked in a commercial laminated film in terms of water absorption, Hunter color parameters(L, a, b) and organoleptic properties(overall color/appearance, flavor) during 6 months of storage at ambient(20oC, 70% RH) and accelerated(40oC, 90% RH) conditions. Moisture content of packed white ginseng(initial 8.44%) linearly increased with storage period, thereby reaching to about 10% (r=0.9966) in ambient and more than 15%(r=0.9886) in accelerated conditions, respectively, at the 6th month of storage. The storage at severe conditions resulted in remarkable changes in Hunter's color values, decrease in whiteness(L) and increase in redness(a) and yellowness(b), while both treatments, phosphine and irradiation less than 5kGy, did not cause any significant changes in color parameters. Phosphine fumigation was shown detrimental to overall flavor of white ginseng(p<0.01), however or ganoleptic qualities of stored samples were effectively maintained by irradiation less than 5kGy(p< 0.05). As the index on the guality of white ginseng stored at severe conditions its organoleptic quality was highly correlated with moisture content(r= 0.9777) and Hunter color values(over 0.9), suggesting the critical values of 15.5% moisture and 72.56, 7.15, 21.45 in Hunter's L, a, b values, respectively.

• Food Science and Preservation
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• v.20 no.4
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• pp.532-538
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• 2013

This study was done in order to monitor the quality properties of the granule using Bokbunja (Rubus coreanus Miquel) extracts. In order to prepare the granule depending on operational parameters such as content of Bokbunja extract ($X_1$, 0.4~1.2 g), sugar content ($X_2$, 6~10 g) and citric acid content ($X_3$, 0.1~0.3 g), a response surface methodology was applied to monitor the optimum recipes on the organoleptic properties and Hunter's color. The optimum recipe on the organoleptic color showed extract content of 0.96 g, sugar content of 7.05 g and citric acid content of 0.232 g. The optimum recipe on the organoleptic flavor showed extract content of 0.86 g, sugar content of 6.04 g and citric acid content of 0.215 g. The optimum recipe on the organoleptic taste showed extract content of 0.92 g, sugar content of 6.39 g and citric acid content of 0.251 g. The optimum recipe on the overall palatability showed extract content of 0.86 g, sugar content of 6.65 g and citric acid content of 0.272 g. The response surface of the Hunter's color b value was similar to the response of the overall palatability; therefore, the optimum conditions accepted by the consumers were 0.8 g Bokbunja extract content and 0.6 g sugar content in the Hunter's color a value of 6.0.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.410-413
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• 1991

Prefried chicken patties were irradiated at dose levels of 0, 2, and 4 kGy using $Co^{60}$ source and stored at $3{\pm}1^{\circ}C$ and $-10{\pm}1^{\circ}C$, separately for the evaluation of color and sensory characteristics. Irradiation dose of 4 kGy slightly darkened the internal color of chicken patties. Except for the internal portion of the frozen samples, an increase (p<0.05) in Hunter 'L' values was observed for both the surface and interior of patties during storage. Upon refrigerated storage, Hunter 'a' values, both on the surface and internally, decreased as the storage period progressed. Only storage period affected (p<0.05) the Hunter 'b' values of patty surfaces and interiors. No difference (p<0.05) in odor, taste, color, and texture of the patties was observed for irradiation dose and storage period as evaluated by triangle tests except between 2 kGy and 4 kGy irradiated samples before forzen storage.

• Food Science of Animal Resources
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• v.21 no.4
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• pp.323-328
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• 2001

Meat quality of the domestic pork carcasses(n=330) classified in 3 groups according to the Hunter L values postmortem($\leq$50, 50.1∼55.0 and $\geq$55.1) was investigated. The carcass temperature(3, 5, 10 and 15hr postmortem) and temperature falling rate of postmortem increased as the Hunter L value increased. The pH postmortem(pH$\_$ohr/, pH$\_$24hr/) decreased as the Hunter L value decreased. In physical traits, the water holding capacity(WHC) increased and the purge loss decreased as the Hunter L value increased. However, shear force, cooking loss and fat hardness were not significantly different among different. Hunter L value groups(p<0.05). The meat color indices(CIE L*, a*, b*, chroma, hue and ΔE) increased as Hunter L value increased. The sensory characteristics had no significant difference among different Hunter L value groups(p<0.05). In conclusion, the results suggested that Hunter L values were related with pork quality such as temperature, pH, physical traits and color.

• Journal of the East Asian Society of Dietary Life
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• v.8 no.2
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• pp.155-161
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• 1998

Response surface methodology (RSM) was used for optimizing preparation conditions and monitoring the quality of buckwheat mook prepared using buckwheat starch. The textures(hardness, adhesiveness, cohesiveness and gumminess) of buckwheat mook were decreased in inverse proportion to the increase of water content. the L and b values of Hunter color parameters in buckwheat mook were increased in proportion to the increase of water content. However, The a value of Hunter color parameters of buckwheat mook were decreased in inverse proportion to the increase of water content. Organoleptic properties(color, form, taste and mouth-feel) of buckwheat mook showed a maximum score in 700ml(water content), 14min(gelatinization time)

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.1
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• pp.55-60
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• 2009

This study was conducted to measure tea surface colors using the visible bands ($400{\sim}700$ nm) with near-infrared spectroscopy (NIRS). The surface colors of 117 tea products were measured with a colorimeter. The $a^*/b^*$ (CIE color scale) or a/b (Hunter color scale) ratios in different tea products accounted for about 99.7% of the variation in fermentation degree (FD), indicating that the $a^*/b^*$ (a/b) ratio is a very useful trait for assessing fermentation degree. Also tea powders were scanned in the visible bands used with NIRS. Calibration equations for surface colors and fermentation degree were developed using the regression method of modified partial least-squares (MPLS) with internal cross validation. The equations had low SECV (standard errors of cross-validation), and high $R^2$ (coefficient of determination in calibration) values with $0.779{\sim}0.999$, indicating that the whole bands ($400{\sim}2500\;nm$) with NIRS could be used to rapidly measure traits related to surface color, fermentation degree and other chemical components in tea products with high precision and ease at a time.