• Journal of the Korean Society of Food Science and Nutrition
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• v.32 no.1
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• pp.47-51
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• 2003

To evaluate the quality of commercial ginger tea, we compared physicochemical (sugar content, pH, acidity, color, viscosity, transparancy) and sensory (7-point scoring test, 18 experienced panel members) characteristics of commercial ginger tea with home-made one. Additionally, we assessed the opinion of Food and Nutrition specialists, about commercial ginger tea. Questionaires were hand delivered to 530 subjects consisted of University students and faculties of Department of Food and Nutrition at 8 cities (Seoul, Incheon, Youngin, Taejon, Chungju, Taegu, Kwangju, Pusan) in Korea and the complete data of 328 subjects were statistically analyzed using SPSS Program for Window (mean, ANOVA, $\chi$$^2$). The questionaires were consisted of sociodemographics, frequency and occasion of purchasing, opinion of quality and improvement points. Commercial ginger tea was lower in transparancy, Hunter color (L and b value) and viscosity than home-made one. However, commercial tea was not significantly different in sugar content, pH, acidity and Hunter color a value compared to home-made one. Also, among sensory attributes, over-all preference and flavor, sweetness were not significantly different between commercial and home - made one, However, scores of color, taste and pungency of home-made ginger tea were significantly higher than commercial one (p<0.05). Factors to be improved for commercial ginger tea were in the order of ginger content (28.6%), flavor (25.2%) and sweetness (24.5%).

• Korean journal of food and cookery science
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• v.25 no.2
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• pp.150-159
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• 2009

The purpose of this research was to improve the quality of Sulgidduk by additions of green tea or rosemary powder to enhance its functional properties and antimicrobial effects. The green tea or rosemary powders were added to the Sulgidduk at different levels (1 or 3%), and color values, textural characteristics, sensory qualities, pH values, and acetic acid values were evaluated. With higher amounts of green tea or rosemary powder, the L-values of samples decreased and a-and b-values increased. Texture profile analyses indicated that hardness was significantly different among all the samples. The sensory evaluation results showed that the 1% addition of green tea or rosemary powder did not cause significant differences in overall acceptability, flavor, or taste. During storage, pH values decreased in all groups and the control group showed the lowest value. Acetic acid values increased during storage and the control group showed the highest value in the last stage of storage. Finally, the L- and a-values of samples did not change significantly during storage.

• The Journal of Natural Sciences
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• v.1
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• pp.21-31
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• 1987

A pulse shape of a pulsed TEA $CO_2$ laser in analyzed theoretically by the use of Computer simulation. Since the laser operates $10.6\mum$ P-20 line, regular band, the pulse shape is obtained by adding the hot band R-23 effect to the regular band $10.6\mum$ P-20. The results are well agreed to the experimental results.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.1
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• pp.47-51
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• 2004

Green tea, which is high in polyphenols, is thought to have hypocholesterolemic effects. The present study was performed to further elucidate the hypocholesterolemic actions of green tea, specially the catechin and (-)-epigallocatechin gallate (EGCG) for their effects on the diet-induced hypercholesterolemia in rats. Male Sprague-Dawley rats were fed with green tea-free diet (control), diets containing 4% green tea powder (GTP), 1.0% green tea catechin (catechin) or 0.5% epigallocatechin gallate (EGCG) for 7 wks. All diets that were provided green tea contained approximately 0.5% EGCG Hypercholesterolemia was induced by adding 1% cholesterol and 0.5% cholic acid to all diets. There were no differences in food intake among groups. The green tea treatments showed significant improvement in the serum levels of total cholesterol, LDL-cholesterol, triacylglycerides and atherogenic index in the following order; EGCG>Catechin>GTP (p<0.05). The serum HDL-cholesterol level was highest in the EGCG-treated group. The catechin or EGCG diet up-regulated by 5 times the enzyme activity of hepatic cholesterol 7$\alpha$ -hydroxylase (CYP7Al) compared to control diet (p<0.05). Hepatic CYP7Al mRNA level paralleled tile increases in the CYP7Al activity. These results suggest that the EGCG in the green tea may account for the hypocholesterolemic effect by the induction of CYP7Al gene expression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.3
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• pp.1448-1457
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• 2014

Geriatric illness is increasing with aged population ratio due to a prolonged average life span. Research studies with therapeutic approach using oriental herbs have been attempted, but the very few studies of oriental herbal tea as a healthy drink have done as a health care. This study was performed to identify the effects of oriental herbal tea on the physiological function and behavioral change of elders at geriatric facility. A quasi-experimental design using a nonequivalent control group, pre-post test was used. Total 38 of elderly population (20 of experimental group and 18 of control group) was recruited. 100mL of a type of oriental herbal tea developed for this study was given to each subject 3 times a day for 30 days (from May to June 2013). The health scan analyzer and questionnaire for behavioral change were used to measure dependent variables. The data was analyzed by SPSS/WIN 18.0. After drinking the oriental herbal tea, more significant improvement on blood circulation (t=-4.466, p<.001), liver function (t=-2.855, p=.007), brain function (t=-2.545, p=.015), bone density (t=-6.125, p<.001), blood sugar (t=-4.180, p=<.001) and emotional factor (t=2.389, p=.023) as the sub-variable of behavioral change were found in the experimental group than control group. This study shows that oriental herbal tea can be effective on the physiological function and emotional relief of the elders. Therefore the tea can be utilized as an effective intervention for the health of elders in geriatric facility.

• Food Science and Preservation
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• v.12 no.1
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• pp.36-42
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• 2005

The purpose of this study was to investigate the component and quality characteristics of green tea. Four kinds of green tea powder obtained from Hwagae area were evaluated the component of carbohydrates, protein crude fat and crude ash. Also the content of ascorbic acid, minerals and polyphenols in green tea powder were evaluated. Quality characteristics of green tea powder was evaluated by Hunter's colur value and sensory evaluation. Green tea was composed of $9.2\~11.8\%$ of moisture, $4.9\~6.1\%$ of crude ash, $5.2\~6.1\%$ of crude fat, $22.5\~26.4\%$ of protein and $50.4\~55.1\%$ of cabohydrates. The content of total ascorbic acid in green tea powder was $312\~392mg/100g$ and dehydiuascorbic acid was $157\~176mg/100g$. The contents of minerals in green tea powder sodium was $340\~580mg/100g$, magnesium was $242\~320mg/100g$, potassium $223\~278mg/100g$ me calcium $145.7\~238.7mg/100g$. Polyphenol content of green tea powder was $7.8\~9.3\%$ which was the highest in A and the lowest in B. Hunters color values of green tea, lightness(L) was $52.3\~69.6$, redness(a) was $0.11\~-5.61$, yellowness(b) was $14.23\~23.34$, which were better in green tea C and D than green tea A and B. From sensory evaluation of green tea powders, green tea D obtained the significant highest scores in color, flavor and overall quality(p<0.05) and followed by green tea C, Green tea powder C and D which have high levels of protein and ascorbic acid were evaluated as good quality in color and sensory evaluation.

• Journal of dental hygiene science
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• v.22 no.1
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• pp.57-66
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• 2022

Background: This study aimed to investigate the effect of selecting commercially available blending teas and applying them to bovine teeth on color change over time. Methods: After selecting healthy bovine teeth, using a cutting-disc, 105 specimens with a dimension of 5×5×3 mm were prepared, and 15 specimens were distributed to each group. Black tea was used as a positive control, water was used as a negative control, and blended tea of five types was used as an experimental group. First, pH and buffering capacity were measured with a pH meter, and tooth color was determined using a spectrophotometer before immersion in the blending tea solution and 1, 5, 7, 14, and 21 days after immersion. Thereafter, the shape change of the enamel surface was observed using a scanning electron microscope, and SPSS ver.26 was used to analyze the color change. Results: The average pH of the five blending teas in the experimental group was 3.78, and the pH of group 3 (strawberry rhubarb) was the lowest at 3.22. The pH levels of black tea and water were 5.19 and 7.30, respectively. The buffering capacity was the highest in group 3 at both pH levels of 5.5 and 7.0. The L^*a^*b^* color change according to immersion time was the largest in group 4 (rooibos yellow flower), and the amount of color change was large in black tea and group 4. As a result of observing the enamel surface of bovine teeth, changes in the surface shape were noted in all groups immersed in the experimental solution for 21 days, except for water. Conclusion: There was a significant difference between the experimental groups in terms of color change according to the immersion time, and color and enamel surface changes were observed in black tea and all experimental groups, except for water.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.5
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• pp.752-757
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• 2000

Response surface methodology was used to optimized soaking and roasting conditions and monitor organoleptic properties of roasted Platycodon grandiflorum tea. In soaking and roasting processes based on the central composite design with variations in threonine/sucrose concentration for soaking of Platycodon grandiflorum, roasting temperature and roasting time, coefficients of determination ($R^2$) of the models were above 0.86(p<0.05) in organoleptic properties. The maximum conditions predicted for each corresponding organoleptic properties of roasted Platycodon grandiflorum tea were 1.64% threonine concentration, 137.83$^{\circ}C$ and 27.76 min in aroma, 1.46% threonine concentration, 136.1$0^{\circ}C$ and 25.19 min in taste, and 1.39% threonine concentration, 136.44$^{\circ}C$ and 29.05 min in overall flavour. The optimum condition ranges for organoleptic properties of roasted Platycodon grandiflorum tea were soaking in 1.40~1.64% threonine concentration, and roasting at 136.10~137.9$0^{\circ}C$ for 25.19~29.00 min.

• Journal of the East Asian Society of Dietary Life
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• v.11 no.4
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• pp.305-314
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• 2001

The study was conducted to investigate the effect of added green tea and black tea powder on the quality of bread during storage. Tea bread was prepared with 0.1% and 2% concentration of green tea (GT) and black tea(BT) powder. The crude fat contents of GT 2% group and BT 2% group were significantly higher than those of control group. GT l% group and BT l% group. The loaf weight of the control group was the lowest and its loaf volume was the highest. Especially, GT 2% group had the lowest loaf volume. The internal lightness value of control group was the highest. the redness value of BT 2% group and the yellowness value of GT 2% group were the highest. GT 2% group was significantly higher in hardness and gumminess and BT l% group was higher in cohesiveness and springiness. After 5 day storage, the retrogradation of GT 2% group was the highest and that of BT 2% group was the lowest among groups. After 5 day storage. pH. titratable acidity and total colony count of GT 2% group was the lowest and those of control group was the highest. The sensory score of control, GT l% and GT 2% group were evaluated higher than others. The shelf-life of tea breads were prolonged to 1~3 days by adding green tea powder and black tea powder as compared with the control group. but It must be considered the way to increase the quality of bread in loaf volume and retrogradation.

• Korean journal of food and cookery science
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• v.15 no.3
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• pp.224-230
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• 1999

The purpose of this study was to find out the optimal mixing ratio of green tea powder, sugar, and water for the preparation of Seolgiddeok through Response Surface Methodology based on the color, sensory, and texture test. The oganoleptic and textural properties of Seolgiddeok prepared with various concentrations of green tea powder (0% (control group), 0.5% (GT-0.5 group), 1% (GT-1.0 group), 1.5% (GT-1.5 group), 2% (GT-2.0 group)), and their quality changes during storage were also investigated. The optimal mixing ratio of green tea powder, sugar, and water for preparing the best quality Seolgiddeok was 1.0%, 12%, and 22%, respectively. The proximate composition of green tea powder was 21.70% of crude protein, 8.49% of crude lipid, 2.95% of reducing sugar, and 6.40% of ash. The contents of crude lipid, reducing sugar, and catechins in Seolgiddeok added with a green tea powder were increased with increasing the content of green tea powder. The hardness and gumminess of GT-1.0 group were the lowest among four groups, whereas GT-1.0 and GT-2.0 groups had the lowest cohesiveness. While the control group was the lowest in adhesiveness, the springness was not significantly different among all groups. GT-0.5 and GT-1.5 groups were the highest in sweet taste and colorfulness, respectively. However, GT-1.0 group had the best overall quality. Total microbial numbers, the acidity and pH in Seolgiddeok during storage were decreased with increasing green tea powder content, and especially those of GT-1.0 and GT-1.5 groups were relatively the lower than others. The “L” value (lightness) of the control group (no additives) was the highest among five groups, and the value was decreased with storage period, and especially GT-0.5 groups had the lowest brightness. The“a”value (reddness) of the control group was the highest, followed by GT-0.5, GT-1.0, GT-1.5, and GT- 2.0 group in order. The“b”value (yellowness) was increased with the increase of green tea powder content. Above results indicated that GT-1.0 group showed the best quality of Seolgiddeok through organoleptic and rheology tests.