• Title, Summary, Keyword: teas

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A Study of the Consumer's Purchase Behavior and Willingness-to-Pay on Flower Tea (꽃차의 소비자 구매 행태 및 지불의사에 대한 연구)

  • Yang, Sung-Bum;Lee, Seog-Won
    • The Korean Journal of Food And Nutrition
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    • v.26 no.2
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    • pp.295-300
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    • 2013
  • The objective of this study is to propose the motivation of the analysis on consumer's purchase behavior and willingness-to-pay for flower tea. Therefore, we survey the purchase behaviors on flower teas as compared with leaf teas such as green teas. We also analyze the willingness to purchase and pay for such teas. The reasons for consuming flower teas are 'flavor', 'beauty/diet', 'health', consecutively. Consumers prioritize 'safety', 'quality', 'price', and 'design' when purchasing flower teas. Nevertheless, it is also essential to consider 'flavor' as a quality factor. It is necessary to differentiate the process and marketing strategies for the development of flower teas.

Detection of Radiation-Induced Hydrocarbons in Green, Black and Oolong Teas

  • Kausar, Tusneen;Lee, Jung-Eun;Noh, Jung-Eun;Kwon, Young-Ju;Kwon, Joong-Ho
    • Preventive Nutrition and Food Science
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    • v.9 no.3
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    • pp.222-226
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    • 2004
  • Hydrocarbons induced by gamma-irradiation of green, black, and oolong teas were analyzed to determine whether the hydrocarbons can be used as markers for detecting post-irradiation of these teas. The samples were irradiated at 0, 2.5, 5, 7.5, and 10 kGy. Detection was attempted by extracting fat from the teas, separation of hydrocarbons with florisil column chromatography, and identification of hydrocarbons by gas chromatography-mass spectroscopy (GC-MS). Concentration of hydrocarbons increased with the irradiation dose. The major hydrocarbons in irradiated green, black, and oolong teas were 1-tetradecence (14:1), pentadecane (15:0), 1,7-hexadecadiene (16:2), 1-hexadecene (16:1), 8-heptadecene (17:1), and heptadecane (17:0). Radiation-induced hydrocarbons in teas were 1,7-hexadecadiene and 8-heptadecene. These compounds were not detected in non-irradiated samples, so the hydrocarbons (16:2, 17:1) can be used as markers for detecting post-irradiation of the teas. Furthermore, detection of hydrocarbons after 12 months storage at room temperature remains a suitable method for identifying irradiated teas.

Korean Green Tea by Ku Jeung Ku Po′s I. Analysis of General Compositions and Chemical Compositions (구증구포(九蒸九)에 의한 녹차 제조 I. 일반성분 분석 및 화학적 조성)

  • 전정례;박금순
    • Korean journal of food and cookery science
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    • v.15 no.2
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    • pp.95-101
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    • 1999
  • This study was carried out to prepare green teas by traditional roasting manufacturing process, Ku Geung Ku Po and to determine the quality charateristics of the green teas by examining the change of their main components induced during this roasting process. The content of total sugars in unroasted tea leaves was 7.82%. Its content of roasted teas was decreased by increasing the number of roasting and there was significantly differences between samples. The content of total sugars in 9th roasted green tea was 3.98%. The total nitrogen contents of green teas produced by this process were 4.96∼6.38%. The more the number of roasting and the less content of tannin in green teas. And the ratio of total nitrogen and tannin in tea leaves 21.97 but its ratio in 9th roasted tea was increased to 45.54. The ascorbic acid in tea leaves consisted in 1,820.3 mg/100g but its content was decreased by increasing the number of roasting process. Whereas the content of caffeine in green teas was not reduced significantly by this traditional method. Of all amino acids, green tea produced by Ku Jeung Ku Po was rich glutamic acid, lysine and aspartic acid. And especially, phenylalanine, which was rarely found in other green teas, was abundant in these green teas. The compositions of glutamic acid and methionine were increased as increasing the number of roasting process but those of aspartic acid and arginine decreased by these processing. The main fatty acids of Ku Jeung Ku Po green tea were linolenic acid, linoleic acid and palmitic acid and the contents of unsaturated fatty acid in green teas were composed over 70% of total fatty acid. And the fatty acid contents in green teas were not affected during Ku Jeung Ku Po's process. The contents of minerals in these teas was rich in the oder of potassuim. magnessuim and calciumim, and these contents were not observed the prominant change during the process.

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Physical and Microbiological Approach in Proving the Identity of Gamma-irradiated Different Teas

  • Kausar, Tusneem;Kim, Byeong-Keun;Kim, Dong-Ho;Kwon, Joong-Ho
    • Food Science and Biotechnology
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    • v.14 no.1
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    • pp.1-5
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    • 2005
  • Photostimulated luminescence (PSL), thermoluminescence (TL), electron spin resonance (ESR), and direct epiflourescent filter technique/aerobic plate count (DEFT/APC) were applied to detect dried green, black, and oolong teas irradiated between 0-10 kGy. Teas irradiated at 2.5 kGy and higher showed over 5000 photon counts/60 sec, while non-irradiated teas yielded 650-1000 photon counts/60 sec. TL glow curves for minerals separated from teas were detected at about $300^{\circ}C$ with low intensity in non-irradiated samples, whereas around $150^{\circ}C$ with high intensity in all irradiated samples. Ratio of $TL_1/TL_2$ based on re-irradiation step, showing lower than 0.1 and higher than 1.44 for non-irradiated and irradiated samples, respectively, enhanced reliability of TL results. ESR measurements for irradiated teas showed signals specific to irradiation. Log DEFT/APC ratio increased with irradiation dose; this result could be applied to identify irradiated tea samples.

Effect of Fermentation Time on the Chemical Composition of Mulberry (Morus alba L.) Leaf Teas (발효시간이 뽕잎차 구성성분에 미치는 효과)

  • Bae, Hui-Ae;Baek, Hyeon;Park, Hae-Il;Choung, Myoung-Gun;Sohn, Eun-Hwa;Kim, Sam-Hyun;Kim, Dae-Su;Chung, Ill-Min;Seong, Eun-Soo;Yu, Chang-Yeon;Lim, Jung-Dae
    • Korean Journal of Medicinal Crop Science
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    • v.19 no.4
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    • pp.276-286
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    • 2011
  • Morus alba (Mulberry) leaves were exposed to fermentation for varying amounts of time: no fermentation (0 min, MANF), medial fermentation (10 h, MAMF), and full fermentation (24 h, MAFF). The chemical compositions of the teas were determined and compared with those of commercial Camellia sinensis teas. The results showed that mulberry leaf teas contained significantly higher amounts of ash and fat than Camellia sinensis tea. Compared with Camellia sinensis teas, all mulberry leaf teas contained significantly more total free amino acids (24.26~54.25mg L-glutamic acid equivalent $g^{-1}$), but the concentration of caffeine was relatively low for mulberry leaf teas. High thiamine, riboflavin, and niacin contents were found in all mulberry leaf teas, but ascorbic acid and pyridoxine were found at higher levels in Camellia sinensis teas than in mulberry leaf teas. Color measurements demonstrated that mulberry leaf tea infusions generally had lower $a^*$ (greenness) and $b^*$ (yellowness) values than Camellia sinensis tea infusions. All infusions exhibited low turbidity levels (less than 10%). The contents of total phenols were measured as 71.8 and 74.9mg 100 $ml^{-1}$ infusion in MANF and MAFF, respectively, but the MAMF tea infusion showed significantly lower total phenols (64.6mg 100$ml^{-1}$ infusion). The total flavonoid contents of mulberry leaf tea infusions were lower (8.9~20.6mg 100 $ml^{-1}$ infusion) than those of Camellia sinensis teas and thus had lower antioxidant capacities (DPPH: 326.8~526.9 ${\mu}M$ trolox equivalent $g^{-1}$ and FRAP: 364.6~387.6 ${\mu}M$ trolox equivalent $g^{-1}$) than Camellia sinensis teas. The amounts of ${\gamma}$-aminobutyric acid (GABA) and rutin were higher in fermented mulberry leaf teas; the level of GABA increased with increasing fermentation time and the content was highest in MAFF, but rutin content was highest in MAMF.

Effects of Compost Tea Making from Differently Treated Compost on Plant Disease Control

  • Tateda, Masafumi;Yoneda, Daisuke;Sato, Yukio
    • Journal of Wetlands Research
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    • v.9 no.1
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    • pp.91-98
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    • 2007
  • Antifungal activity of compost teas was evaluated in vitro and in vivo experiments. In vitro test, fourteen compost teas were produced using five different composts and through six different methods for compost tea production. Eleven pathogenic fungi were used as indicators of antifungal activity of compost teas. In vivo test, one of the compost teas used in vitro test was sprayed to cucumber leaves which were infected with powdery mildew in order to evaluate antifungal activity of compost tea. From the results of the tests, it was found that all compost teas used this study showed antifungal activity and the proper application of compost teas against pathogenic fungi for obtaining optimal effects was important to know.

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Changes in Antioxidant Activity with Temperature and Time in Chrysanthemum indicum L. (Gamguk) Teas During Elution Processes in Hot Water

  • Eom, Seok-Hyon;Park, Hyung-Jae;Jin, Cheng-Wu;Kim, Dae-Ok;Seo, Dong-Wan;Jeong, Yeon-Ho;Cho, Dong-Ha
    • Food Science and Biotechnology
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    • v.17 no.2
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    • pp.408-412
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    • 2008
  • Determining the elution of water-soluble substances from herbal teas is an important factor in their efficient use in terms of taste, perfume, and content of health-related components. The antioxidant activity and content of catechins in commercial Chrysanthemum indicum (gamguk) teas were determined for optimum elution conditions. The water extract of gamguk teas did not differ significantly in yield compared to methanol extracts and showed stronger antioxidant activity. Catechin contents in gamguk teas were 8-18% of the extracts when individual peaks in high-performance liquid chromatography analysis were compared to standard catechin peaks. Gamguk teas exhibited faster release of antioxidants, and the antioxidant activity was positively correlated with the thermal treatments. Gukhwacha (GC) was the best tea for rapid release (30 sec) of antioxidants with the $50^{\circ}C$ treatment, whereas antioxidants in other teas were relatively slower released.

Analytical Method for Methylxanthin, Catechin, and Theaflavin Determinations in Korean Commercial Teas by HPLC (차에 함유된 methylxanthin류, catechin류 및 theaflavin류의 HPLC에 의한 동시분석법)

  • Kim, Soo-Yeun;Kozukue, Nobuyuki;Han, Jae-Sook;Lee, Kap-Rang
    • Korean Journal of Food Science and Technology
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    • v.38 no.1
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    • pp.5-9
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    • 2006
  • Method for separation and quantification of methylxanthins, catechins, and theaflavins in Korean commercial teas (green, oolong, and black teas) was developed using reversed phase high-performance liquid chromatography (HPLC). After extraction with hot water, tea compounds were separated on Inertsil ODS-3v $(5\;{\mu}m)$ column, eluted with gradient of 7% acetonitrile and 93% of 20 mM phosphate buffer mixture for 7 min. Column effluent was monitored at 270 nm. This technique was effective for analyses of m methylxanthins, catechins, and theaflavins in teas and biological samples. In green and oolong teas, two kinds of methylxanthins and 7 of catechins were identified, whereas 4 theaflavins were only identified in black tea. Among seven catechins in green and oolong teas, EGCG showed highest amount, whereas ECG was highest in black tea. (theaflavins were found only in black teas) In all teas, theobromine content was lower than that of caffeine.

Properties of Pulsed Photostimulated Luminescence and Thermoluminescence for Detection of Gamma-Irradiated Teas during Storage

  • Kausar, Tusneem;Kim, Byeong-Keun;Yang, Jae-Seung;Byun, Myung-Woo;Kwon, Joong-Ho
    • Preventive Nutrition and Food Science
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    • v.9 no.3
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    • pp.227-231
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    • 2004
  • Green, black and oolong teas were irradiated by $^{60}$ Co-gamma rays (0~10 kGy) and were investigated for detection of irradiation treatment using pulsed photostimulated luminescence (PPSL) and thermoluminescence (TL) during storage. Teas irradiated at 2.5 kGy or more showed a photon count of greater than 5000 counts/60 sec while the non-irradiated yielded only 650~1000 count/60 sec. Correlation coefficients between irradiation dose and photon counts/60 sec were 0.8951, 0.7934 and 0.9007 for green, black and oolong teas, respectively. The TL glow curves for minerals isolated from the non-irradiated teas were situated at about 30$0^{\circ}C$ with a low intensity, but for irradiated samples were approximately 15$0^{\circ}C$ with a high intensity. The TL ratios (TL$_1$/TL$_2$), calculated from values after initial radiation and then after re-irradiation of the teas, were below 0.1 for the non-irradiated samples and higher than 1.44 for all irradiated samples, enhanced the reliability of the identification results for TL. The signal intensity of PPSL and TL for irradiated teas decreased with the lapse of post-irradiation storage time at room temperature but was still distinguishable from that of the non-irradiated samples even after one year.

Effect of Gamma Irradiation and Fumigation on the Biological Qualities of Green, Black, and Oolong Teas

  • Kwon, Joong-Ho;Kausar, Tusneem;Kwon, Yong-Jung;Kim, Jung-Ae;Huh, Eun-Youp;Lee, Kyeong-Yeoll;Saeed, Shafqat
    • Food Science and Biotechnology
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    • v.15 no.1
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    • pp.1-4
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    • 2006
  • The biological qualities of green, black, and oolong teas were monitored by observing their microbial decontamination and insect disinfestation following gamma irradiation (0-10 kGy) and fumigation (MeBr or $PH_3$) during 6-month storage at room temperature. Plodia interpunctella Hubner was found as an important quarantine pest in teas used. In a comparative study, both treatments were found to be effective in disinfecting the stored samples. An irradiation dose of 5 kGy was sufficient to control all microorganisms related to the quality of teas, while fumigation with methyl bromide and phosphine showed no appreciable decontamination effect on the microorganisms. As a result, irradiation was found an effective alternative to fumigants for the improvement of biological tea qualities during storage.