Lidiany Mendonça Zacaroni

Influência da luz e da temperatura sobre a oxidação do óleo essencial de capim-limão (Cymbopogon citratus (D.C.) Stapf)

The identification of the chemical compounds of the essential oil was performed with a gas chromatograph coupled to a mass spectrometer. The oil was left in the presence and absence of light and submitted to different temperatures to evaluate its stability. The yields of the major compounds were evaluated every fifteen days. Citral and myrcene, the major compounds of the essential oil, were degraded over time in both the presence and absence of light, but temperature only influenced the degradation of myrcene.

Determination of ethyl carbamate in cachaça produced from copper stills by HPLC

Ethyl carbamate (EC) is a common substance in fermented foods and drinks, and its quantification is important because of its carcinogenic nature and its usually presence in alcoholic beverages. The present work involved the development and validation of an analytical method for the evaluation of EC in cachaça by HPLC-FLD after previous derivatization with xanthydrol. The method presented a mean recovery of 94.88%, an intra-day precision of 4.19% (30.0 μgL(-1)) and 3.32% (75.0 μgL(-1)), a coefficient of determination (r(2)) equal to 0.9985, and limits of detection and quantification equal to 6.39 and 21.32 μgL(-1), respectively. The results show that the analytical method is accurate, reproducible and linear over the concentration range from 5.0 to 160 μg of EC per litre. The method was applied to the analysis of EC in cachaça, the analyses being rapid and efficient.

Caracterização e quantificação de contaminantes em aguardentes de cana

The objective of the present study was the evaluation of the presence of organic and inorganic contaminants in samples of aged cachaca from the South of the state of Minas Gerais. Furfural, methanol and copper were determined by colorimetric reactions, while the analyses of ethyl carbamate and acrolein were performed by GC/MS and HPLC, respectively. High levels of furfural and copper were obtained. All samples showed concentrations below the established by legislation for the ethyl carbamate, and for acrolein, only one sample showed higher levels. Methanol was not detected in the samples.

Evolution of the concentration of phenolic compounds in cachaça during aging in an oak (Quercus sp.) barrel

A cachaca, tradicional e popular bebida brasileira, e obtida por meio da destilacao do mosto fermentado de cana de acucar. Dentre as etapas do processo de producao da bebida, o envelhecimento natural consiste em armazena-la em recipientes de madeira apropriados por um tempo determinado, onde ocorrem alteracoes na composicao quimica, aroma, sabor e cor da bebida. Este trabalho teve como objetivo realizar um acompanhamento da composicao fenolica em diferentes periodos de envelhecimento da cachaca em tonel de carvalho (Quercus sp.). Foram realizadas coletas periodicas durante o periodo de envelhecimento da cachaca em tonel de carvalho e realizaram-se analise de treze compostos fenolicos utilizando a tecnica de cromatografia liquida de alta eficiencia com detector de arranjo de diodos (HPLC-DAD). Foi constatado um aumento progressivo na concentracao dos compostos analisados ao longo do periodo analisado, sendo que os compostos encontrados em maior concentracao foram siringaldeido e acido galico.

Potencial fungitóxico do óleo essencial de Piper hispidinervum (pimenta longa) sobre os fungos fitopatogênicos Bipolaris sorokiniana, Fusarium oxysporum e Colletotrichum gloeosporioides

The objective of this study was to evaluate the in vitro antifungal activity of the essential oil of the leaves of Piper hispidinervum against Bipolaris sorokiniana, Fusarium oxysporum and Colletotrichum gloeosporioides. For the biological tests, using the bioanalitic test in vitro the concentrations of 100, 200, 500, 1000, 1500 and 2000 µg.mL-1 the essential oil. This were incorporated into PDA (potato dextrose agar) medium in order to evaluate fungal mycelial growth or inhibition. The statistic design used was completely randomized, with four replicates. In the concentration of 200 µg.mL-1, observed inhibited complete the phytopathogens Bipolaris sorokiniana while the Fusarium oxysporum and Colletotrichum gloeosporioides this is occurred in the concentration of 1000 µg.mL-1.

Identificação do carbamato de etila durante o armazenamento da cachaça em tonel de carvalho (quercus sp) e recipiente de vidro

The objective of the present study was the identification and quantification of ethyl carbamate (EC), by HPLC-FLD, after different periods of storage in an oak (Quercus sp) barrel and a glass vessel. The concentration of EC in the cachaca samples varied from <LD to 17.46 µg L-1, for the period during which the cachaca was stored in an oak barrel, and <LQ to 18.51 µg L-1 for the cachaca stored in a glass recipient. The storage of the beverage in both the oak barrel and the glass vessel resulted in a significant increase in the concentration of this contaminant.

Determination of Phenolic Compounds and Coumarins in Sugar Cane Spirit Aged in Different Species of Wood

The identities and quantities of the phenolic compounds and coumarins in twelve samples of sugar cane spirit aged in Quercus sp., Amburana cearensis, Cariniana legalis, Castanea sativa Mill, Ocotea sp., Cotyledon orbiculata L., and Hymenaea sp. casks were determined. These compounds have a direct influence on the sensory characteristics of aged beverages; some of them are considered to be markers for the aging process. The analysis of phenolic compounds was performed by HPLC. Solid phase extraction (SPE) was also used for the determination of coumarins. The concentrations of the principal compounds extracted varied according to the species of wood. The concentrations of total phenolic compounds ranged from 0.08 for a sample stored in a 4000-L jatobá barrel for a period of six months to 40.9 mg · L−1 for a sample aged in a 50000-L oak barrel for a period of 48 months. The use of the SPE technique removed interfering compounds from the samples, thereby improving the detection of coumarin.

Influência da secagem sobre o rendimento e composição química dos compostos voláteis das raízes de Piper piscatorum Trel. & Yunck. (Piperaceae)

In this study, we evaluated the yield and chemical composition of volatile compounds obtained from fresh, dried at 30 and 40 oC respectively of Piper piscatorum, employing the technique of hydrodistillation. The volatile were chemically characterized by GC-MS and GC-FID. The main volatile compounds were selin-11-en-4-a-ol (57,63 ± 3,07%; 53,95 ± 1,56% and 56,20 ± 0,43%) and benzyl benzoate (15,40 ± 0,36%; 16,32 ± 0,85% and 15,04 ± 0,24%).The drying of the raw material reduced yield of volatile compounds, changing their chemical compositions.

Determination of acrolein, ethanol, volatile acidity, and copper in different samples of sugarcane spirits

Seventy-one samples of sugarcane spirits from small and average size stills produced in the northern and southern Minas Gerais (Brazil) were analyzed for acrolein using HPLC (High Performance Liquid Chromatography). Ethanol and copper concentrations and volatile acidity were also determined according to methods established by the Ministry of Agriculture, Livestock and Supply (MAPA). A total of 9.85% of the samples tested showed levels of acrolein above the legal limits, while the copper concentrations of 21.00% of the samples and the volatile acidity of 8.85% of the samples were higher than the limits established by the Brazilian legislation. The concentration of acrolein varied from 0 to 21.97 mg.100 mL-1 of ethanol. However, no significant difference at 5% of significance was observed between the samples produced in the northern and southern Minas Gerais. The method used for determination of acrolein in sugarcane spirits involved the formation of a derivative with 2,4-dinitrophenylhydrazine (2,4-DNPH) and subsequent analysis by HPLC.

Influência da temperatura de secagem sobre o rendimento e a composição química do óleo essencial de Tanaecium nocturnum (barb. Rodr.) bur. & K. Shum

The yields and chemical compositions of the essential oils obtained by steam distillation of the fresh and dried (30 and 40 oC) leaves, stems and roots of Tanaecium nocturnum are reported. The identification and quantification of the volatile constituents were accomplished by GC/MS and GC/FID, respectively. The essential oils obtained from the various parts of the plant were constituted mainly of benzaldehyde. Large losses and variations in the quantities of the components during the drying process were observed. The presence of mandelonitrile in higher concentration in the stem and roots indicates that this species produces cyanogenic glycosides.