• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.80-86
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• 1998

This work was designed to determine the optimum roasting conditions with application of a pressure roaster for improving the roasting process of the Polygonatum sibiricum tea which has been roasting with a traditional method. Soluble solid content of the Polygonatum cibiricum tea was 63.16% in the tea roasted at 0.85kgf/$\textrm{cm}^2$(roasting pressure) and 13.9min(roasting time) which were maximum point by the ridge analysis. The optimum conditions predicted for each corresponding sensory properties of the Polygonatum cibirium tea were 0.87kgf/$\textrm{cm}^2$ and 9.2min in color, 0.89kgf/$\textrm{cm}^2$ and 9.7min in sweet 0.72kgf/$\textrm{cm}^2$ and 5.4min in burnt flavor, 0.89kgf/$\textrm{cm}^2$ and 9.9min in appetizing flavor, 0.87kgf/$\textrm{cm}^2$ and 9.3min in aftertaste, 0.89kgf/$\textrm{cm}^2$ and 10.0min in aroma, and 0.88kgf/$\textrm{cm}^2$ and 9.6min in overall acceptability of the tea. The optimum conditions based on the soluble solid content and sensory properties of the Polygonatum cibiricum tea, were 0.83~0.88kgf/$\textrm{cm}^2$ and 9.7~10.4min.

• 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.

• Food Science and Preservation
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• v.11 no.2
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• pp.148-153
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• 2004

The organoleptic properties of granule tea was optimized for granulation of Polygonatum sibiricum Delar(Dunggulle) tea for exclusion of scorched smell and increase of consumption. The length of 2 mm was suitable to cutting size of Dunggulle for preparation of the roasted Dunggulle. The optimum sensory conditions for aroma of Dunggulle granule tea showing 7.85 organoleptic score were 80.61% in ratio of Dunggulle extracts to total extracts, 12.77% in content of total extracts and 37.33% in rate of glucose to total sugar. The highest score of overall palatability was 5.96 at 61.11% in rate of Dunggulle extracts to total extracts, 13.79% in content of total extracts, and 60.92% in rate of glucose to total sugar.

• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.776-783
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• 1997

Response surface methodology was applied to determine the optimum roasting conditions (roasting temperature and time) for the high-quality Polygonatum odoratum tea which has been roasting with a traditional means. As quality criteria of Polygonatum odoratum tea, water-soluble solids, browning color, total phenolic compounds and electron-donating ability were proportionally increased with increased temperature and time of roasting conditions up to around $145^{\circ}C$ and 55 min, respectively, while they were decreased under the extended-roasting conditions. The optimum roasting temperature and time based on the organoleptic overall acceptability were $146^{\circ}C$ and 52 min, respectively. On the basis of superimposed contour maps for the tea characteristics, the optimum range of roasting conditions were $135{\sim}140^{\circ}C$ and $58{\sim}64$ min. Predicted values at the optimum conditions $(137^{\circ}C,\;60\;min)$ were in good agreement with experimental values.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.894-898
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• 1999

Aroma components of Ookjook tea made from Polygonatum involucratum Maxim roots were collected and identified. The extraction of aroma compounds was accomplished by a simultaneous distillation and extraction method using a Likens and Nickerson's extraction apparatus. The concentrated extract was analyzed and identified by GC and GC-MS. The most abundant aroma components of this tea were furanic compounds including 2-furfural, 2-methyl-dihydro-3(2H)-furanone, 2-acetylfuran and 5-methylfurfural. These compounds seem to be originated from the thermal degradation of carbohydrates during the roasting process. Alkylpyrazines and acids including propionic acid increased slightly during the period of manufacturing process of Ookjook tea. Furanic compounds originated from the thermal degradation of carbohydrates and alkypyrazines from aminocarbonyl reaction seemed to be the important contributors to the aroma of the Ookjook tea.

• Food Science and Preservation
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• v.4 no.2
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• pp.155-162
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• 1997

This work was designed to determine the effect of steaming-Pretreatment on Physicochemical and functional properties of roasted Polygonatum odoratum roots. Steaming treatments led to some reduction in the contents of water solubles, such as total solid, reducing sugar and free-amino nitrogen of the unroasted samples. Moreover, roasting processing caused decrease in reducing sugar and free-amino acid, with increase in total soluble solid and browning color of the samples, which showed the dependence of steaming treatment as well as roasting temperature. Electron-donating ability and nitrite-scavenging ratio of the samples were also highly developed along with roasting processing at 17$0^{\circ}C$ within 35min. Considering the physicochemical and some functional parameters of water extracts of roasted samples, roasting at above 14$0^{\circ}C$ for over 55min or at 17$0^{\circ}C$ for around 35min was recommendable for the higher quality of Polygonatum odoritum tea, which conditions were similarly adapted for both steamed and unsteamed samples.

• Korean journal of food and cookery science
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• v.17 no.4
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• pp.353-358
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• 2001

The leaves of Duchung(Eucommia ulmoides), an oriental medicinal plant, have a peculiar aroma of Chinese medicine and astringent taste, which make the consumer be reluctant to Duchung leaf tea. Therefore, the purpose of this study was to develop a mild flavored Duchung leaf tea by mixing with other plants. The flavor patterns of developed tea were analyzed using an electronic nose. Polygonatum odoratum and Elsholtzia splendens were used for improving the flavor of Duchung leaf tea. The addition of 20, 30 and 40% of Polygonatum odoratum improved the overall acceptance in hedonic sensory evaluation. The flavor pattern of the tea was described by principal component analysis(PCA) and the resistance ratio(R/cub gas/R$\_$air/) of sensors. The PCA plot was also used to explain the mild flavor of the tea, which was extended from the right side(positive value of the first principal component) to the left side(negative value). Analysis by using an electronic nose with metal oxide sensors could be applied to detect whether mixed Duchung leaf tea was acceptable or not.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.6
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• pp.1316-1320
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• 1999

Antioxidative effect of ethanolic extracts of various tea materials(Camellia sinensis, Cassia tora, Lyc ium chinense, Polygonatum odoratum, Schizandrae chinensis) on red pepper seed oil was investigated. Ethanolic extracts were added to red pepper seed oil at a concentration of 0.05%(w/v). Two experimental conditions were employed : 50$\pm$0.1oC for 45 days and 150$\pm$3oC for 24 hours. Oxidation of red pepper seed oil was determined by measuring peroxide value and acid value. Electron donating ability(EDA) and total phenolic contents of each extract were also determined. The result showed that the extracts possess an antioxidative activities. The effectiveness of them was in the following order: C. sinensis>C. tora>P. odoratum>S. chinensis >L. chinense. Ethanolic extracts of C. sinensis showed substantially higher EDA value and total phenol contents than other tea materials. These results indicate that the antioxidative effect was strongly related with EDA and total phenol contents.

• Korean Journal of Food Science and Technology
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• v.32 no.3
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• pp.507-512
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• 2000

The headspace flavors of roasted tea, prepared with steamed and nonsteamed polygonatum roots, were absorbed in solid-phase microextraction(SPME) fiber coated with $65\;{\mu}m$ of carbowax/divinylbenzene(CW/DVB) and analysed by GC-MS. The absorption conditions of SPME fiber for equilibrated headspace were selected as $60^{\circ}C$ and 30 min. In a comparison for both samples roasted at $130^{\circ}C$ for 15 min, gas chromatograms showed a similar pattern in overall profiles between steamed and nonsteamed samples before roasting, but some differences were observed in peak characteristics. From 40 separated peaks, 25 compounds were identified with both GC-MS and retention time comparison. The pyrazines including 2,3-dihydro-3,5-dihydroxy-6-methyl-4H-pyran-4-one, 2,5-dimethyl-4-hydroxy-3(2H)-furanone, 2-acetyl-1-pyrroline, etc. were higher in their contents in nonsteamed-roasted sample than steamed-roasted one. In particular, steamed-roasted polygonatum showed higher contents of acetic acid(8.17%) and hexanoic acid(5.43%) than the corresponding compounds of nonsteamed-roasted one, 2.40% and 2.00%.

• Korean Journal of Food Science and Technology
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• v.35 no.1
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• pp.28-32
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• 2003

As part of studies on the high quality dunggule tea, made of Polygonatum odoratum root with different growth year were analyzed for their flavor compounds. The quality attributes related to flavors were compared between raw and roasted samples which were treated at $130^{\circ}C$ for 15 min. Free sugars in the roots were mainly composed of fructose ($3.59{\sim}4.83%,\;d.b.$), sucrose ($1.78{\sim}2.49%$), and glucose ($1.60{\sim}1.80%$). Threonine ($1,239{\sim}1,444\;mg/100g,\;d.b.$), arginine ($589{\sim}689$), histidine ($289{\sim}370$) were three major free amino acids. The root grown for three years showed the highest content in total free sugar and amino acids (p<0.05). There was negligible difference in proximate composition and Hunter's color parameter depending on the growth year of the roots. However, sensory scores on color, taste and aroma were highest in 3 years' root, which is found most suitable for the preparation of dunggule tea. The roasting of 3 years old root significantly reduced the content of fructose and sucrose (p<0.01). It caused most apparent changes in the decreasing amount of threonine and in the decreasing rate of lysine, showing the significant decrease in total free amino acid content (p<0.01).