• Korean journal of food and cookery science
• /
• v.21 no.3 s.87
• /
• pp.346-353
• /
• 2005

CThis study used HPLC to analyze the contents of 7 kinds of catechins, 4 kinds of theaflavins, and 2 kinds of methylxanthines in the following 6 kinds of commercial Korean tea: 2 green, 2 black, 1 jasmine and loolong. The following ranges in the 13 tea components of the 6 samples by ethanol extract were evaluated in mg/g: (-)-epigallocatechin, 0(black tea and jasmine tea) to 14.19(green tea); (-)-catechin 0; (+)-epicatechin, 0.62(bran rice-green tea) to 2.91(black tea); (-)-epigallocatechin gallate, 4.59(black tea) to 43.96(jasmine tea); (-)-gallocatechin gallate, 0.58(black tea) to 5.80(jasmine tea); (-)-epicatechin gallate, 5.63(bran rice-ueen tea) to 48.06(jasmine tea): (-)-catechin gallate, 0.26(black tea): theaflavif 0 to 3.66(black tea): theaflavin-3-gallate, 0 to 6.94(black tea): theaflavin-3'-gallate, 0 to 4.01(black tea); theaflavin-3,3-digallte, 0 to 10.25(black tea); caffeine, 4.60(bran rice-peen tea) to 26.44(black tea); and theobromine, 0.10(bran rice-green tea) to 1.81(jasmine tea). The contents of all components were lower by water extract than by ethanol extract. Therefore, total catechin (100.55, 45.88 mg/g) and theobromine (1.81, 0.86 mg/g) contents in jasmine tea, and theaflavin content (24.88, 1.36 mg/g) in black tea by ethanol and water extract were the highest. Caffeine content was the highest in black tea(96.48 mg/g) for the ethanol extract, and in jasmine tea (12.38 mg/g) for the water extract.

• Culinary science and hospitality research
• /
• v.14 no.4
• /
• pp.1-13
• /
• 2008

The antioxidant activity and quality characteristics of bread made from waxy black rice flour(WBRF) and green tea powder were investigated. The bread was manufactured with 1% of green tea powder and 10, 20, 30 or 40% of WBRF(w/w). The group of 40% of WBRF and green tea powder significantly showed the highest bread weight and volume. Lightness(L value) and yellowness(b value) decreased, but redness(a value) increased with increasing WBRF contents in mixture. Hardness, gumminess and chewiness were the lowest in the control group, but springiness was the lowest in the group of 40% of WBRF and 1% of green tea powder. The sensory scores of appearance, external and crumb color, grainy in the group of 40% of WBRF and 1% of green tea powder were the significantly lowest. Overall acceptabilities of the groups of 10% and 30% of WBRF with 1% of green tea powder were not significantly different from the control group. The group of 40% of WBRF and 1% of green tea powder showed the highest DPPH radical scavenging effect and TEAC content. Thus, if the mixture of green tea powder and WBRF would be used, it might be proper to use 1% of green tea powder and 10% of WBRF mixture considering the quality and antioxidant activity of bread.

• The Korean Journal of Food And Nutrition
• /
• v.11 no.5
• /
• pp.521-527
• /
• 1998

Removabilities of heavy metals(Cd and Pb) by the tea materials (barley-tea, corn-tea, jasmin-tea, brown rice-green tea, black-tea, cassia tora-tea, persimmon peel-tea, and rice-tea) in the tea-water were studied in the various conditions ; particle size of tea (20, 40, 70 mesh), concentration of heavy metal (25, 50, 100 ppm) and extraction temperature(20, 30, 50, 100$^{\circ}C$). The removabilities by the tea solids were increased as the particle size decreased, concentration of heavy metal increased, and extracting temperature increased. Of the nine kinds of tea, Cd and Pb removability by jasmin-tea was highest. In addition, heavy metal removability by cassia tora tea was better than that of other tea as extraction temperature was increased.

• Journal of Life Science
• /
• v.25 no.1
• /
• pp.68-74
• /
• 2015

Recently developed black waxy rice with a giant embryo ('Nunkeunheukchal', BGE) was selected and processed to produce high quality nutritional food. BGE contains high levels of several phytochemicals with antioxidant activities, as well as other reported health beneficial properties. In addition, the giant embryo has high protein, lipid, and amino acids contents. Within the free amino acids, ${\gamma}$-aminobutyric acid (GABA), a major inhibitory neurotransmitter, has long been used for treating the aftereffects of brain injuries and stroke. A method for manufacturing pop-rice and black rice tea by popping process in BGE is provided to increase a taste, nutrition and functionality. The produced 'pop-rice' showed increased protein (11.3%) and lipid (3.7%) contents compared with control variety, IB ('Ilmibyeo'). In addition, melanoidin related products, polyphenol and functional amino acid contents were increased by the popping process. Pop-rice tea made of BGE showed the highest extraction of total sugar, glucose, raffinose and sucrose (4 times higher than brown rice) by hot water. Scavenging activity ($SC_{50}$) of processed BGE rice powder showed strong antioxidative activity of 0.24 mg/ml using DPPH and 1.82 mg/ml using ABTs method. Thereafter, these results suggested that the popping processed rice of BGE could be one of the promising materials for healthy food development.

• Culinary science and hospitality research
• /
• v.12 no.4 s.31
• /
• pp.213-224
• /
• 2006

This study was to investigate the factors affecting drinking Korean traditional beverages and the drinking habits of college students in Seoul. The research was carried out by asking them to drink 10 kinds of traditional drinks. They were composed of 45.5% of boys and 54.5% of girls who were $18\sim21$ years old, studying food related science (63.9%), and mostly (86.6%) living in a nuclear family in collective residents (60.4%) like an apartment. The number of students whose family's monthly incomes were over 3 million won was the largest as 37.1%. Their mothers were housewives (58.4%) mostly aged $46\sim50$ as 47.0%. In the research on the preference of students for the traditional drinks, most of them, 78.7%, showed their liking for the drinks because of their good taste (61.%). The number of students who answered they got the drinks by homemaking was the largest as 39.6%. Most of them, 66.3%, preferred fruit drinks, 19.8% soda drinks, 11.4% traditional drinks and 2.5% functional drinks. 31.2% of the drinks mostly taken at home was green tea, followed by sweet rice drink, Shik-hae. Among the drinks coming into the market, sweet rice drink was preferred in general as 25.7%, and the next was green tea 16.8%, ume drink (Maesil tea) 14.9%, rice tea 13.9%, fruit punch (Sujeonggwa) 11.4%, black tea 7.9%, honey tea 4.5%, ginseng tea 2.5% and jujube tea 2.5%. In the research on 'whether the students had experience preparing the traditional drinks or not', many of them, 62.4%, answered "No". And in the questionnaire asking on 'whether they liked to receive a training on making traditional drinks or not', 87.6% of them showed their wish to get the training. In the question on the reason why the students did not like to take the training on traditional drinks, the number of students who answered that it was complicated and hard to prepare was the largest as 53.0%.

• Journal of the Korean Society of Food Culture
• /
• v.21 no.1
• /
• pp.8-16
• /
• 2006

This study was performed by questionnaire to investigate the preference and intake frequency of Korean traditional commercial beverages. The subjects were consisted of 320 participants in Daegu and Kyungpook area. 'Chain market' scored 49.4% as purchasing place of traditional beverages. 'Tea bag' scored 31.6% as the favorite package of traditional beverages. On the reasons of drinking traditional beverage 'good for health' scored the highest with 31.3% respondents, followed by 'good smell' with 14.4%. Coffee and traditional tea were the choice of beverage after having a rich meal and on occasion of entertaining guests. The favorite foods in ordinary days were 'tea', 'alcohol', 'ice cream', 'nuts' and 'cookie'. More than thirty percent of the respondents, both male and female, raised the need of improvement in taste of traditional beverage. In the intake frequency, Korea traditional beverages obtained 1.80 points as a whole. 'Green tea' scored highest(3.40points) while 'mulberry-leaf tea' received the lowest score of 1.31 points. The preferred Korean traditional drinks were 'greed tea', 'shick hae', 'citron tea', 'misitgaru', 'maesil tea', 'rice tea' in the order. On the other hand, the preference for 'mulberry-leaf tea', 'boxthom tea', 'ginger tea', 'chrysanthemum tea' and 'omija tea' was very low. The people who are on twenties preferred 'shick hae', 'honey tea', 'citron tea', 'black tea' and 'misitgaru' more than the other generation.

• Journal of Food Hygiene and Safety
• /
• v.16 no.4
• /
• pp.295-299
• /
• 2001

This study was performed to survey and evaluate the contents of caffeine in commercial palatability foods by HPLC. The contents of caffeine in commercial palatability foods were 9.0~49.2 mg in black tea, 35.9~141.4 mg in coffee, 12.4~48.0 mg in green tea, 7.1 ~16.5 mg in brown rice green tea, 22.8 mg in cocoa tea, 10.3~25.0 mg in cola and 10.0~48.2 mg in ice bar(coffee) respectively. The contents of caffeine extracted from black tea, coffee(roasted beans) and green tea were rapidly increased for five minutes from the extraction initiation, and were not nearly changed after ten minutes. Moreover, the caffeine contents were increased until 10$0^{\circ}C$ of extraction temperature.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
• /
• 2002.08a
• /
• pp.109-119
• /
• 2002

Rice production in Korea began to rise significantly after 1970. Rice is the dominant food in Korea and most of the rice production (about 95%) is consumed as cooked rice. it provides over 4,000Kj of energy per capita per day. Apparent rice availability in 2000, 93.6Kg of milled rice per person annually. The non-allergenic character of rice offers a sound basis for development of products for markets for all age groups. Whole grains are washed rice, coated rice, enriched rice in Korea. Utilization of rice as food can be categorized three categories in Korea; direct food use, processed foods, and brewing. Rice for direct consumption include regular whole grain, precooked rice, brown rice and specialty products such as aseptic cooked rice, retort cooked rice and rice burger. Rice used for processed foods includes that for cereal, soup, baby food, snack, cake, noodle, brown rice tea, and minor unclassified uses. Rice use for brewing is for the production of fermented rice wine. The use of rice for direct food is by for the greatest of the three uses. Although direct food accounts for the largest domestic consumption, a significant quantity of rice is used in processed products. The use of rice by-products as human food should not be over looked. Utilization of by products(rice germ, rice bran) requires a specialized technology. Typical type of rice is black rice. When cooked, black rice gives a black color to cooked rice. Glutinous rice performs specific functions in several commercial products such as dessert, gravis, cake and snack. Rice starch production is quite limited because of the high cost of making of starch. Rice processed products in Korea are occupied small parts of total rice production compared to Japan. Rice cake (Garadog) is the principal from of rice product consumed in Korea. Rice cake and snack is usually prepared from non-glutinous milled by washing, grinding, steaming, cooling and packaging. Rice cake will be continued to be a major rice product in Korea. Rice products represent a means to study variety differences in rice grain quality, since the processing magnifies differences not normally detected from more boiling. Recently, rice processing companies in Korea are about 400 ones which uses rice about 160,000tons. New rice processed products and modified traditional products must be developed and diversified with high quality and processing properties of rice processed products are improved.

• Journal of Applied Biological Chemistry
• /
• v.56 no.2
• /
• pp.113-117
• /
• 2013

Ten major residual biogenic amines including toxic histamine and tyramine were investigated in the plant-based minor Korean fermented food. From the analyses of pickled vegetables, fermented vegetable extracts, fermented tea, black garlic and herbal rice wines, more than 100 mg/kg of histamine were found in pickled soy leaf and pickled mulberry leaf, and also over 1,000 mg/kg of total biogenic amines were found in pickled soy leaf. No sample was found over in black garlic, fermented tea, fermented vegetable extracts and herbal rice wine, less than 100 mg/kg of histamine and/or 1,000 mg/kg of total biogenic amines were observed. Interestingly, all the tested rice wines were found to be over 100 mg/kg of agmatine residue.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.32 no.5
• /
• pp.723-727
• /
• 2003

The antioxidant activities and their antioxidant compounds of a group of teas obtained in local markets were investigated. A total of 18 teas were tested for their antioxidant activities based on their ability to scavenge ABTS (2,2'-Azino-bis-3-ethylbenzothiazoline-6-sulfonic acid) cation radical and DPPH (1,1-diphenyl-2-picrylhydrazyl) free radical. The former was expressed as mg of ascorbic acid equivalents per 1 tea bag (L-ascorbic acid equivalent antioxidant capacity, AEAC) and the latter was expressed as percentage of electron donating activity (EDA%). A good correlation of AEAC and EDA was observed between the two methods. The concentrations of total polyphenolics and flavonoids in tea extracts were measured by spectrophotometric methods. Total ascorbic acid was determined via the 2,6-dicholoroindophenol titrimetric method. According to the AEAC value and EDA, black tea, brown rice green tea, green tea, herb tea and malva tea showed relatively high antioxidant activities. Polyphenolic compounds were the major naturally occurring antioxidant compounds found in teas and the high concentrations of polyphenolic compounds were observed in black tea, green tea and herb tea. Overall, six teas out of 18 teas tested in the study showed better antioxidant activities and higher amounts of total polyphenolic compounds.