• Journal of the Korean Society of Tobacco Science
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• v.18 no.2
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• pp.107-112
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• 1996

The occurrence and chemical properties of grey tobacco leaves (Type III) found in 1995 crop of flue-cured tobacco cultivated in paddy field were investigated to compare with those of normal leaves. Cured leaves of NC82 were separated by visual characters into 3 classes of slight, fair and severe symptoms of grey leaf by the percentage of grey parts to whole leaf area. Number of samples classified with discoloring portion was the order of greyish brown > reddish brown > greyish yellow, respectively. Grey leaves of this type were mostly found among the leaves harvested from upper stalk position, and it was estimated that growth rate of upper leaves also influenced on the occurrence of grey leaves. Grey leaves showed remarkably lower b* and L* values than those of normal leaves, while a* value was mostly higher in grey leaves. These tendencies in chromatic aberration showed more remarkable difference in the degree of grey symptoms. Chemical analyses of grey leaf samples indicated that they contained less total nitrogen and nicotine, and more total sugar and starch than those of normal leaves. In chemical traits, these tendencies were accordance with the degree of grey symptoms, and within the same leaf, grey parts were decreased in total nitrogen and ether extract content compared with those of normal parts, but there was no difference in nicotine and Cl contents. Key words : grey leaf tobacco (type III), grey symptom, color, chemical properties.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.133-137
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• 2000

The bulk curing experiment to improve the quality of flue-cured leaves were carried out to evaluate relationship between the modified(3 step-up) drying and conventional drying method in bulk curing process. Modified drying method was somewhat higher values in yellowing color index of cured leaves, and less brittle than those in conventional drying program. As to the chemical properties, there was no difference in chemical component levels in cured leaves between the modified and the conventional methods, while the major chemical compounds in relation to aromatic essential oil of cured leaves showed mostly higher level in the modified method than that in conventional drying method. Additionally 3 step-up drying method increased the tobacco quality by 2 % in price per kg compared with conventional drying method.

• Korean Journal of Environmental Agriculture
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• v.29 no.4
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• pp.417-420
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• 2010

The rust fungi are biotrophic fungal pathogens that cause serious disease on Perilla leaves in Korea. The effect of some commonly used chemical preservatives (sorbic acid, D-sorbitol, propionic acid and benzoic acid) against Perilla rust was investigated in this study. Results of this investigation showed that all the preservatives were effective against Perilla rust except benzoic acid. There was no growth of rust spores on the Perilla leaves treated with 0.1% of preservative even after 21 days of preservation. However, 0.01% of preservative also showed remarkable reduction of rust spores on the Perilla leaves as compared to the control groups. Thus, the results of this study indicated that the chemical preservatives used might be useful to control the growth of rust fungi on Perilla leaves.

• Journal of the Korean Society of Tobacco Science
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• v.22 no.2
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• pp.143-150
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• 2000

This study was carried out to investigate the effect of storage period on the physico-chemical properties of tobacco leaves expanded by $CO_2$. The flue-cured and burley tobacco leaves produced from 1996 to 1999 were processed, and stored for that year or 3 years in processing plant. As compared with 1996 crop, the expanded rate of flue-cured tobacco leaves in 1999 crop was higher approximately 18%, while that of burley was higher about 10%. The filling capacity of cigarettes was decreased as storage time became shorter, but the combustibility was improved. The rate of large particles (over 3.36mm) of expanded tobacco showed decreasing tendency as the storage period became longer. The change rate of chemical contents in tobacco leaves between before and after expansion had no significant difference among corp years. The tar and CO contents of cigarettes smoke were reduced in the case of flue-cured tobacco leaves as storage time became shorter, while they were slightly increased in the case of burley tobacco leaves. The ammonia content of burley leaves was decreased remarkably in 1996 and 1999 crop.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.2
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• pp.139-143
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• 1998

The occurrence and physico-chemical properties of flat leaves found in 1997 curing trial related to the prevention of occurrence of flat leaves at bulk curing of flue-cured tobacco were investigated and compared with those of normal leaves. Cured leaves of NC82 were separated into 4 classes of none, slight, fair and severe symptoms of flat leaf by the percentage of flattened parts to whole leaf area. The flat leaves were mostly found among the leaves of lower stalk position, and it was estimated that growth rate of lower leaves also influenced on the occurrence of flat leaves. In chromatic aberration of cured leaf, flat leaves showed remarkably lower b and L values than in those of normals but there was no difference in a value. On the other hand, in chemical analyses of flat leaf samples, nicotine, total sugar, ether extract and total nitrogen contents were decreased with the degree of flat symptoms. In physical properties, filling capacity of cured leaves was decreased with the degree of flat symptoms comparing with those of normal leaves, while shatter index was showed a reverse tendency, and then within the same leaf, flat parts were decreased in total sugar, ether extract and filling capacity compared with those of normal ones, but remarkably increased in shatter index, and there was no difference in nicotine and total nitrogen contents.

• Journal of the Korean Society of Tobacco Science
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• v.21 no.1
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• pp.10-16
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• 1999

Leaves harvested were separated with visual characters into 2 classes such as immature and mature leaves. In the curing process, the prolonged yellowing treatment during yellowing stage was automatically controlled at the different stalk position, and condition of curing process after this period was all the same with conventional ones. In case of prolonged yellowing in immature leaves, increase of price per kg reached to 8 % compared with those of conventional ones. In physical properties, filling capacity and shatter index was decreased with the degree of maturity, and it was equal level in filling capacity of immature leaves between curing method, while shatter index was decreased in prolonged yellowing treatment than that of conventional ones. There was no difference in chemical components between immature leaves of prolonged yellowing and conventional ones. As to the prolonged yellowing of immature leaves, there was decreased in citric and malic acid contents of the nonvolatile organic acids, and it was equal level in all higher fatty acids content of leaves cured by prolonged yellowing treatment compared with in that of conventional curing method. The contents of key compounds such as solanone, damascenone, damascone in the essential oil were lower in prolonged yellowing of immature leaves than those of mature leaves cured by conventional ones.

• Journal of the Korean Society of Tobacco Science
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• v.18 no.1
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• pp.49-53
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• 1996

This experiment was carried out to study the effect of oxygen on chemical composition and physical properties of tobacco leaves during flue-curing. The results obtained were as follows: Starch content decreased and sucrose content increased with increasing oxygen supply during curing. Glucose and fructose of the cured leaves showed high content at the 5-10% oxygen supply. Amino-N and nitrate-N increased with increasing oxygen supply. Total nitrogen and NH4-N showed the lowest value at the 5-10% and 10-15% oxygen supply in the cutters and leaf, respectively. Chlorophyll and chlorogenic acid increased, and total volatile base decreased with increasing oxygen supply. The activity of α-amylase increased at the latter period of flue-curing, and the maximum activity point were delayed 12 hours with increasing oxygen supply. Shatter index of cured leaves decreased with increasing oxygen supply. It was desirable to supply oxygen during flue-curing for the improvement of chemical and physical properties such as starch, total sugar, chlorogenic acid, and shatter index of cured leaves.

• Journal of Applied Biological Chemistry
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• v.64 no.2
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• pp.121-125
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• 2021

Antioxidative, anticoagulant, and α-glucosidase inhibitory effects of 60% (v/v) ethanolic extract from lotus (Nelumbo nucifera) leaves were investigated in vitro. The yield and polyphenol content of the lotus leaves extract were 35.3±1.1% and 186.2±5.2 ㎍ gallic acid equivalents/mg, respectively. The lotus leaves extract effectively scavenged free and cation radicals, and nitrite in a concentration-dependent manner, and possessed potent reducing power. The lotus leaves extract had remarkable anticoagulant and α-glucosidase inhibitory activities as a function of the extract concentration.

• Journal of Plant Biology
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• v.17 no.1
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• pp.15-21
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• 1974

The most commonly grown economical and flue-cured tobacco cultivar Yellow Special A was used in pot-culture tests in order to study Ethrel (2-chloroethyl phosponic acid) effects on accelerating maturity of tobacco leaves in relation to the most adequate level of the chemical useful for field growing, nitrogen level in soil for the most pronounced response, and the most suitable spray period during the growth stages of pre-, post- and topping periods. The following conclusions, thus, were obtained from the present studies; 1. 500ppm Ethrel spray was reconfirmed to be adequate in the practical applications, although the extent of yellow-ripening of tobacco leaves was increased as the Ethrel level increased. The highest leevel treated resulted in causing chemically damaged lesions on leaves and early defoliation. 2. Ethrel-treated leaves showed deeper yellowish tinge to them than those without treatment, while different levels of the chemcial had less influence on the tinge. 3. An adequate level of nitrogen supply to plants favored the Ethrel response, whereas either very low or high level of nitrogen in the soil lowered the chemical effect on accelerating the yellow-ripening. When carbohydrates versus total nitrogen ratio became relatively high, the condition brought out some outstanding Ethrel effects. 4. Chlorophyll level of leaves increased as soil applications of nitrogen level increased, and that also increased carotenoid level of the tobacco leaves. Ethrel-treated leaves showed deeper orange tinge than those without treatment, while the highest level of nitrogen application showed the deepest orange tinge to tobacco leaves. 5. Pre-topping treatment (12 days before topping and flowering) resulted in almost no Ethrel response, and that treatment right on the day of topping, showed response of yellow-leaf ripening at nearly bottom-half leaves of a tobacco plant. The post-topping treatment (12 days after topping) made plants showing full response of Ethrel from bottom to the top leaves of tobacco plant in accelerating the leaf maturity. 6. The extent of Ethrel responses on accelerating yellow-ripening of tobacco leaves was discussed for the modifying influences brought about by certain environmental factors. Discussions were also made about the possible practical applications (particularly for pre-rice planting) and quality difference that may be caused by such growth environments.

• Journal of the Korean Society of Tobacco Science
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• v.20 no.1
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• pp.19-25
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• 1998

The bulk curing experiment to the improve the quality of flue-cured leaves were carried out to evaluate relationship between cyclic curing and conventional curing method. We studied the effect of the cyclic change of wet bulb temperature at the yellowing stage of flue curing on chemical properties of cured leaves. The wet bulb temperature was automatically controlled between preset high($38^{\circ}C$) and low point ($35^{\circ}C$) everyone hour cyclically during 12 hours after starting luring. As a result, the acceleration of the increase in the chemical properties of cured leaves were observed. As to the chemical properties, there was decreased in citric acid, increased in malic acid of the nonvolatile organic acids and all higher fatty acids content of leaves cured by this method compared with in that of conventional curing method, while a major chemical compounds in relation to aromatic essence of cigarette smoke in essential oil components of lured leaves was mostly higher in this method than those of conventional ones, and it was evaluated that there was decreased in CO, TPM, Tar, and $CO_2$ content of the cigarette smoke comparing to the conventional luring method.