The repellency, insecticidal activity and repellency duration effect of dagalet thyme, Thymus quinquescostatus against Asian tiger mosquito, Aedes albopictus larvae and adults was investigated. Whole plant body of T. quinquescostatus proved to have the repellent activity of 91.2% against A. albopictus adults. The constituents of T. quinquescostatus were analyzed using GC-MS as follows: α -pinene (1.1%), α-thujene (2.7%), camphene (1.3%), myrcene (4.7%), α-terpinene (5.0%), ɤ-terpinene (33.0%), ρ-cymene (8.3%), β-caryophyllene (4.0%), β-bisabolene (8.9%), thymol (29.9%), and carvacrol (1.2%). Among them, thymol has the perfect repellency on A. albopictus adults and confirmed the electrophysiological response on the antenna of A. albopictus adults. To enhance the maintenance, vanillin was added. Duration of effectiveness of mixture with vanillin (0.18 : 0.36 ㎕/㎠) were significantly more prolonged than thymol alone. The constituents on its original oils were applied onto A. albopictus larvae. The thymol, α-terpinene and carvacrol (LC50 = 9 mg litre-1) revealed to have high insecticidal activity.
양액재배시 적합한 배지와 배양액농도를 선발하고자 본 실험을 수행하였으며, 공시작물은 백리향(Thymus vulgaris L.)으로 하였다. 배양액의 농도는 European Vegetable R&D Center에서 개발한 herb 배양액(EC=2.4)을 0.5, 1, 2, 3배로 조제하여 사용하였다. 배지는 고형배지로 펄라이트 단용, 코코피트 단용 그리고 펄라이트와 코코피트 혼용(50:50 v/v)을 사용하였고, 비고형배지로는 DFT를 사용하여 총 4처리로 하였다. 생육은 다른 배지 처리구보다 담액수경에서 가장 좋았다. 펄라이트와 담액수경에서는 배양액농도가 높을수록 생육이 감소하였으나 코코피트는 1배, 혼용 배지는 2배 처리구에서 가장 높은 생체중을 보였다. 엽록소와 비타민 C의 함량 또한 다른 배지 처리구보다 담액수경에서 더 높은 함량을 보였다. 배지의 종류에 따른 무기물 함량은 NO3-N과 Mg를 제외하고 모두 코코피트에서 가장 높은 함량을 나타내었다. NO3-N의 함량은 담액 수경에서 1000 ppm 내외의 낮은 함량을 보였다. 따라서 본 실험의 결과, 백리향의 생육은 DFT를 사용하여 herb배양액 0.5배(EC =1.2mS/cm)농도로 재배한 처리구에서 가장 좋은 생육을 보였다.
The purpose of this study was to evaluate the quality of fresh-cut lettuce after a washing treatment with aqueous thyme extracts of differing concentration. Four different concentrations of thyme extract were employed: 0.001% (w/v, TEA), 0.005% (w/v, TEB), 0.01% (w/v, TEC), 0.05% (w/v, TED), while distilled water was used as a control. Measurements of O2 concentration, CO2 concentration, total aerobic bacteria, CIE L*, a*, b*, browning index, total phenolic contents and enzymatic activities were investigated on day 0, 1, 3, 5, and 7 at 10 . The O2 concentration in TEB were higher than those in other samples during storage, and the CO2 concentration in TEB and TEC were significantly lower than in other samples on day 7. There was no significant difference in the total aerobic bacteria counts between treatments (p<0.05). The samples treated with TEB and TEC showed higher L* (lightness) values, but lower browning indexes, total phenolic compound levels, and enzymatic activities (polyphenol oxidase, peroxidase) than other samples during storage. Specifically, on day 7, the browning index of Cont reached 0.25, while those in the TEB and TEC were about 0.15. The L* in Cont decreased from 69.50 to 58.92, while TEB and TEC were values of 65.61 and 63.20, respectively. These results reveal that 0.005-0.01% thyme extract was effective as a washing treatment inhibited the browning of fresh-cut lettuce and is thus expected to be a useful natural extract for maintaining the quality of fresh-cut lettuce.
Experimental purpose was to evaluate growth characteristic and abscisic acid (ABA) responses against salt/drought stresses. In the shoot biomass, creeping thyme was tolerated in mild NaCl stress, ranging 0 to 100 mM, while it was severely reduced in higher salinity. Under constant drought stress, the shoot biomass of creeping thyme showed a worse value compared to that of 100 mM NaCl treatment. Chlorophyll degradation was more severe in immature leaf than mature leaf under salt and drought stresses. In salt stress, immature leaf produced much amounts of ABA compared to mature leaf and also immature leaf showed faster increase of ABA than that of mature leaf. In drought stress, immature leaf responded to stress within 24 hours by the increase of ABA, while mature leaf responded to at 72 hours. Our results recommended that the optimal salinity level of creeping thyme was 50~100 mM NaCl.
The effects of the water extracts from thyme(TM) and tarragon(TG) on shelf-life and quality of kimchi were investigated by measuring the changes in pH, acidity, number of total microorganisms, number of Lactobacillii and Leuconostoc during fermentation at 1, and were tested for antimicrobial activities against Lactobacillus plantarum and Leuconostoc mesenteroides. TM and TG were extracted with water, ethyl ether, ethyl acetate and ethanol. Water, ethyl ether, ethyl acetate and ethanol extracts of TM showed antimicrobial activities against Lactobacillus plantarum and did not observed against Leuconostoc mesenteroides. On the other hand, water, ethyl acetate and ethanol extracts of TG showed antimicrobial activities against Leuconostoc mesenteroides and did not observed against Lactobacillus plantarum. The decrease of pH and the increase of acidity showed lower in kimchi prepared by adding water extracts from TM than in products from TG. The number of total microorganisms were also detected less in the kimchi prepared by adding water extracts from TM. And, the properties of barkless of kimchi measured instrumentally were higher for kimchi prepared by adding water extracts from TM, also maintaining good crispness. The optimal addition amounts of both TM and TG for good overall and spicy taste of kimchi were 0.03%. The results suggested the possible use of the extracts of TM and TG can be successfully used for the quality and extension of shelf-life of kimchi.