• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.271-271
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• 2017

Tartary buckwheat is known for its high rutin (quercetin 3-rutinoside) content which has antioxidant, anti-inflammatory, and anticarcinogenic effects. The buckwheat tea which is popular in Korea, is dependent on the quality of applied processing methods (steaming, dehuling, and roasting). This study focused on the evaluation of changes in rutin and anti-oxidant contents during the processing of tartary buckwheat tea. Raw tartary buckwheat seeds contains the highest quantities of rutin (2,212 mg/100 g D.W.). Soaking in water and steaming the whole seeds of tartary buckwheat significantly decreased its rutin and quercetin contents. Whereas the contents of rutin and quercetin in dehulled groats increased after steaming. The process of roasting with $70-80^{\circ}C$ for 2-3 min significantly decreased the contents of rutin (992 mg/100 g D.W.) and quercetin (12.8 mg/100 g D.W.). In the processing of tartary buckwheat tea, rutin content dropped about 45% in comparison with raw whole seeds.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.5
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• pp.639-645
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• 2017

Differences in bioactive compounds and antioxidant activities of aronia leaf (AL) extracts according to manufacturing conditions such as different number of pan-roasting and different temperatures were investigated. Both total polyphenolic compounds and total flavonoids contents were the highest in six time-pan-roasted AL tea extract ($37.96{\pm}0.48mg$ catechin equivalent/g and $19.96{\pm}0.44mg$ quercetin equivalent/g, respectively) among four tea samples. Antioxidative activities were also the highest in six time-pan-roasted AL tea extract with $IC_{50}$ 0.43 mg/mL and $IC_{50}$ 0.27 mg/mL based on DPPH and ABTS radical scavenging activities, respectively. HPLC analysis revealed that AL tea infusion did not have caffeine regardless of manufacturing conditions, whereas green tea infusion had 3.8 mg/g caffeine. Results demonstrated that AL tea can be expected as caffeine free leaf tea containing antioxidant benefits. Moreover, specific pan-roasting conditions of AL tea would be very important for its functional and sensory attributes.

• Korean Journal of Food Science and Technology
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• v.44 no.1
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• pp.34-40
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• 2012

This study was carried out to investigate the optimal roasting conditions for developing perilla leaf leached tea, which has high functional Perilla frutescens leaves. The roasting processes were carried out with variations in roasting temperature ($120-200^{\circ}C$) and roasting time (15-35 min), the response surface methodology was applied to monitor the changes in qualities of the roasted Perilla frutescens leaves. The antioxidant, bioactive substance in roasted Perilla frutescens leaves, and their extracts were the quality parameters. The total polyphenol and total flavonoid contents increased with time and temperature up to 25 min and $160^{\circ}C$. Antioxidative activities showed a positive correlation with the amount of phenolic compound. Caffeic acid and rosmarinic acid contents increased with time up to a mild temperature, $160^{\circ}C$, while they decreased at high temperatures over $160^{\circ}C$. The optimum roasting conditions selected for developing perilla leaf leached tea were thus $180^{\circ}C$ and 20 min, given the conditions in the above experiments.

• The Korean Journal of Food And Nutrition
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• v.29 no.6
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• pp.1040-1049
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• 2016

In this study, we aimed to develop a mixed tea prepared with roasted mulberry leaf and fruit using response surface methodology (RSM). Roasting of mulberry leaf was by 6 stages, as shown in Fig. 1; and mulberry fruit was roasted in 4 stages, as shown in Fig. 2. Subsequently, physicochemical measurements such as total polyphenol content, nitric oxide production content, and ${\alpha}$-glucosidase inhibitory effect were obtained for each sample. Central composite design was applied to prepare samples containing varying contents of roasted mulberry leaf (RoML) and roasted mulberry fruit (RoMF); subsequently, sensory evaluation was conducted. The total polyphenol content of roasted samples (RoML and RoMF) were significantly higher than that of raw samples (RaML and RaMF), respectively. The nitric oxide (NO) production of roasted samples were significantly lower than that of control (LPS induced RAW 264.7 cell). The ${\alpha}$-glucosidase inhibitory effect of roasted samples was significantly higher than that of raw samples, respectively. Based on the RSM estimation for determination of optimum ratio by sensory evaluation (taste, color, and flavor) among 13 mixed samples, the optimum mixing ratio of RoML and RoMF for taste, color, and flavor were 1.64 g (RoML) and 0.88 g (RoMF), 1.35 g (RoML) and 0.92 g (RoMF), 1.65 g (RoML) 1.03 g (RoMF), respectively. Based on results of three sensory evaluations, mixing ratio comprising 1.54 g of RoML and 0.92 g of RoMF is desirable for delicious tea with functionality.

• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.8
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• pp.1201-1206
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• 2010

As a means to increase the production and consumption of the brown colored rice with high content of GABA ($\gamma$-aminobutyric acid), this study was conducted to develop brown colored rice tea. After roasting at various temperatures and times, color values and GABA content of the brown colored rice were analyzed. Physicochemical properties such as browning, turbidity, reducing sugar, soluble solid, total polyphenol and pH of brown colored rice tea were determined after the rice powder was put into tea bags and leached in hot water. Sensory characteristics were investigated for three kinds of tea roasted at $170^{\circ}C$ for 10, 20 and 30 min. As the roasting temperature and time increased, L, a and b values decreased as well as GABA content. The brown colored rice roasted at $170^{\circ}C$ for 10 min contained the highest content of GABA. Browning, turbidity, reducing sugar, soluble solid and total polyphenol of the brown colored rice tea increased as the roasting temperature and time increased, on the contrary, pH decreased. The brown colored rice tea roasted for 30 min was preferred the most in color, flavor, taste and overall acceptance. From this result, the brown colored rice tea needs to be manufactured by a combination of the brown colored rice roasted at $170^{\circ}C$ for 10 min and 30 min to satisfy the consumer's preference and high content of GABA.

• Journal of the East Asian Society of Dietary Life
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• v.17 no.3
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• pp.409-416
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• 2007

This study investigated changes in the catechin and alkaloid contents of Bosung green tea during different manufacturing processes and storage periods, using HPLC and UV-VIS spectrophotometer analysis. For changes in the catechin and alkaloid contents by roasting technique, we found that EGCG, CG and GCG decreased just slightly by processes performed before roasting, rather than after roasting. In addition, theobromine, caffeine, and ECG changed minimally throughout all the processes. For changes in the catechin and purine alkaloid contents of the green tea leaves during storage, EGCG, ECG, and CAF decreased considerably in the green tea stored at temperatures of $5^{\circ}C$ and $25^{\circ}C$, and they decreased by $20{\sim}30%$ after storage for 1 year. However, a quantitative difference was hardly observed in the catechin and alkaloid contents regardless of storage temperature.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.7-16
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• 2017

BACKGROUND: Increased value added by rapeseed (Brassica napus) by-product and the development of a usable rapeseed functional tea. METHODS AND RESULTS: To develop a usable rapeseed functional tea, the total flavonoid content in the varieties Youngsan, Tammi, Tamra, Naehan, Hanra, Mokpo No. 68, and Mokpo No. 111 was investigated. Effect of three treatments, i.e., drying, leaching, and roasting, on flavonoid contents or flower was tested using multiple processing methods per treatment. Total flavonoid content decreased under the various drying methods, confirming that flavonoid content is heat-dependent. This finding was more pronounced for freezing and oven-drying (15.3 and 13.8 mg/g DW, respectively), with a 10% difference in the total flavonoid content between the two methods. Under leaching conditions, the flavonoid content decreased with increasing treatment time. Notably, roasting methods did not result in loss of flavonoid content. The total flavonoid content in the rapeseed varieties decreased in the following order: Youngsan, Tammi, Tamra, Naehan, Hanra, Mokpo No. 68, and Mokpo No. 111. CONCLUSION: The flavonoid content in rapeseed flower was higher in Youngsan than in the other varieties, under processing conditions such as freeze-drying, leaching at $90^{\circ}C$ for 5 min, and roasting.

• Journal of the Korean Society of Food Culture
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• v.10 no.4
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• pp.241-245
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• 1995

The roasting condition and organoleptic characteristics in Cassia tora tea were investigated. Intact Cassia tora seeds were composed of water 11.6%, crude protein 13.1%, crude fat 4.4%, crude fiber 13.8%, N-free extract 47.2% and ash 4.9%. Organoleptic qualities in Cassia tora tea were sweetness, astringency, tartness, bitterness, roasted coffee like, roasted barley like and burnt smell. Organoleptic qualities were investigated by descriptive analysis method, too. Overall acceptability was increased by roasting but it was low because of formation of bitterness and burnt smell at excessive roasting conditions. Sweetness was the most important factor in organoleptic quality of Cassia tora seeds and the optimum condition for the best quality was $210^{\circ}C$, 20 minutes.

• Journal of the East Asian Society of Dietary Life
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• v.10 no.2
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• pp.136-141
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• 2000

This study was conducted to analyze the properties of the roasted dandelion tea prepared after various pre-treatments such as pre-drying, steaming and air blast drying. The dandelion tea was prepared by roasting the pre-treated dandelion leaves and its total yield, pH, soluble solid content, turbidity, browning and sensory value were evaluated. Total yield and soluble solid content were the highest in case of air blast drying. Turbidity and browning degree were similar in all the teas regardless of their pre-treatment including pre-drying, steaming or air blast drying. The best palatability in the sensory evaluation was obtained at the steaming condition for 60 sec without pre-drying. Longer air blast drying time resulted in the increase in the a and b values. turbidity, browning degree, total yield and soluble solid content in the air blast dried tea.

• Journal of the East Asian Society of Dietary Life
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• v.27 no.4
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• pp.365-377
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• 2017

The objective of this study was to investigate the sensory quality characteristics of coffee under various processing and roasting conditions of green beans. Colombia green bean samples were obtained from three processing methods: natural, pulped-natural, and washed methods. The green beans were roasted differently according to Agtron number: light (Agrton #65), medium (Agtron #55), and dark (Agtron #45). Moisture content, density, color value, pH, and total dissolved solid contents (TDS) were measured, and quantitative descriptive analysis (QDA) with 23 sensory attributes was performed for nine coffee samples. Hunter L values were significantly elevated with the degree of processing but reduced with roasting intensity. The pH values of the nine coffee samples were 5.6~6.2 and significantly increased with intensity of roasting. TDS decreased with an increase in processing and increased with roasting intensity. QDA results show that smoky aroma and nutty and chocolate flavor significantly increased while fruit and floral aroma decreased with intensity of processing. The attributes of brownness, oily surface, smoky aroma, bitter and burnt flavor, and greasy and heavy mouthfeel significantly increased while fruity and floral aroma, black tea, sour and umami flavor, pureness, and softness decreased as roasting intensity increased. Principle component analysis showed the overall significant relationships between 23 sensory attributes and nine coffee samples under different processing and roasting conditions.