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A Series of Novel Esters of Capsaicin Analogues Catalyzed by Candida antarctica Lipases
Tania Diaz-Vidal,Luis Carlos Rosales-Rivera,Juan C. Mateos-Díaz,Jorge A. Rodríguez 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.1
Capsaicin analogues are typically synthetized by condensation of the amide group of vanillylamine with a fatty acid derivative. The enzyme of choice to perform this reaction is Candida antarctica lipase B; however, this enzyme is unable to react with the phenolic substituents of the vanillyl ring. So far, this can only be achieved chemically, resulting in capsaicin esters with higher lipophilicity and less irritation than the parent compound. In need of searching for new capsaicin derivatives, we investigated the transesterification of the phenolic OH group of capsaicin and several capsaicin analogues by Candida antarctica lipase A (CALA) with vinyl esters. Capsaicin esters were successfully synthetized with a reaction yield of 80.6% and 57.5% with vinyl butyrate and vinyl laurate, respectively. When the reactions were performed with capsaicin analogues of different acyl chain lengths, CALA exhibited a noticeable transesterification preference for medium-length capsaicin analogues. In an attempt to explore the catalytic limits of CALA, we performed the transesterification of capsaicin from Capsicum oleoresin. The results showed similar transesterification yields to those obtained with semi-pure capsaicin. Within our knowledge, this is the first report to achieve the synthesis of phenolic OH esters of capsaicin and capsaicin analogues by enzymatic means.
Miguel A. Vallejo,Modesto A. Sosa,Esteban Rivera,Juan C. Azorin,Jesus Bernal,Ricardo Navarro,Emma K. Encarnacion,Luis A. Diaz-Torres 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2016 NANO Vol.11 No.4
In this paper, the co-precipitation method was used to synthesize pure and Ag-doped LiF crystals and the effect of crystalline cube sizes and Ag concentration on the thermoluminescent (TL) response is reported. The synthesized materials were characterized by scanning electron microscopy and their morphology and size distributions were determined. Crystal sizes were found to be strongly dependent on the ethanol:water ratio, varying from 4.1 µm to 150 nm for pure LiF crystals. For Ag-doped samples, the best ethanol : water ratio was found to be 9:1, giving crystals from 0.50 µm to 1.21 µm. A single cubic crystalline phase was determined by XRD for all synthesized samples. The photoluminescence spectra as well as UV-Vis absorbance were also analyzed. The TL response to X-ray irradiation was studied for an exposition of 43 R. Two effects were observed in the TL response. The first concerns with a significant dependence of the TL intensity on the size of the crystals, being larger for the smallest crystals for pure LiF, and second, for Ag-doped samples the TL intensity augmented almost linearly with the Ag concentration.
Screening of Industrial Enzymes for Deproteinization of Shrimp Head for Chitin Recovery
Angel U. Valdez-Peña,Adriana Hernandez-Rivera,Iliana M. De-la-Garza-Rodriguez,Judith D. Espinoza-Perez,Georgina C. Sandoval-Fabian,Nagamani Balagurusamy,Juan Carlos Contreras-Esquivel 한국식품과학회 2010 Food Science and Biotechnology Vol.19 No.2
Food grade proteolytic enzymes were examined for deproteinization of shrimp head. Shrimp head was easily deproteinized by Alcalase® and trypsin at a pH of 8.0. Alcalase was chosen as the most efficient commercial enzyme for deproteinization of shrimp head. Alcalase treatment of shrimp head recorded 61% of weight loss on dry basis and a residual protein of 275 mg/g dried shrimp head. The enzymatically deproteinized shrimp head was later demineralized with lactic acid using microwave radiation at 400W. The combination of enzymatic and physicochemical treatments promoted the chitin recovery from dried shrimp head under eco-friendly conditions.
Evaluation of Novel Platelet Polymorphisms in Stroke. Dichotomic Effect of rs5443 in GNB3
Constantino Martínez,Ana Isabel Antón,Agustina Bernal,María Luisa Lozano,Francisca Ferrer-Marin,Javier Corral,Juan Antonio Iniesta,Vicente Vicente,José Rivera 대한신경과학회 2015 Journal of Clinical Neurology Vol.11 No.1
Jinho Ahn,Sergey K. Gulev,Peter W. Thorne,Frank J. Dentener,Catia M. Domingues,Sebastian Gerland,Daoyi Gong,Darrell S. Kaufman,Hyacinth C. Nnamchi,Johannes Quaas,Juan A. Rivera,Shubha Sathyendranath,S 한국기상학회 2021 한국기상학회 학술대회 논문집 Vol.2021 No.10
IPCC 6차보고서 2장에서는 현재의 지구시스템 상태를 진단하는데 촛점을 맞추고 있다. 먼저 기후변화의 주요 요인이 되는 대기 이산화탄소 농도의 경우, 현재의 농도는 최근 2백만 동안 경험하지 못한 수준이며, 상승속도는 최소 80만 년 동안 100년 시간규모에서 가장 높다. 지난 수십 년 동안의 기후시스템의 주요 인자는 수백 년 또는 수천 년 동안 경험하지 못한 수준으로 올라가고 있으며, 최소한 과거 2000년 동안 경험하지 못한 속도로 변하고 있다. 지구평균표면온도(GMST)는 1850-1900년 대비 2011-2020년에 약 1.09도 증가하였는데, 육지에서는 1.59도, 해양에서는 0.88도 상승하였다. 전지구적 물순환은 적어도 1980년 이후 강화되었고, 대규모 대기순환은 20세기 중반 이후 강화되었을 가능성이 높다. 북극 해빙(sea ice)의 연평균과 여름철 면적은 적어도 1850년 이후 최소가 된 것이 확실하다. 육상 빙권에서의 변화는 전반적으로 수백 년에서 수천 년 규모에서 유래가 없을 정도이다. 20세기 이후의 해수면 상승 속도는 백 년의 시간 규모에서 적어도 3000년 동안 가장 빠른데, 상승이 가속화 되고 있다. 해양에서도 과거 수백 년에서 수천 년 동안 유래없는 현상이 감지되고 있는데, 해양생물 변화의 경우 대규모 해양온난화와 해양화학 변화와 일치한다. 육상생물 또한 대규모 온난화와 일치하는 변화를 보이고 있다. 중기플리오세온난기(Mid-Pliocene Warm Period, 3.3-3.0 백만 년 전) 동안 지구의 이산화탄소 농도가 지금과 비슷했으나, 현재의 지구보다는 따뜻했는데, 과거의 온난했던 시기는 미래 기후를 예측하는데 도움을 준다.