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This study evaluated techniques of extraction of caffeine from decaffeinated coffee samples for application in quality control of industrial decaffeination processes. The extraction was studied using two methods, an aqueous one and another through liquid-liquid partition with chloroform. The objective was to extract the maximum amount of caffeine with the minimum of interference from the matrix and with good repeatability of extraction. After comparing the aqueous extraction and extraction with chloroform, a 23 factorial design was performed to optimize the liquid-liquid extraction. The parameters analyzed in the factorial design were the solvent:sample ratio, extraction time, and filtration or not after extraction. The optimum extraction point was defined using the amount of caffeine extracted as the response factor. Caffeine levels were quantified by capillary electrophoresis according to an analytical method previously optimized and validated. The best extraction condition was achieved through liquid-liquid partition with chloroform, using 30 mL of solvent, 7 min of agitation, and without filtration. This condition showed good repeatability (2.8%, n = 7), recovery of 96.7-107.4%, and removal of interfering matrix. The method was applied to samples of decaffeinated roasted and ground coffee, and instant coffee.

A “green” analytical method is reported for the determination of phenolic acids in mushrooms. The sample preparation involves aqueous extraction based on acid hydrolysis, followed by analysis of extracts by capillary electrophoresis with diode array detector (CE-DAD). A central composite design was used to obtain the optimum conditions for the extraction of compounds from mushrooms, including the concentration of hydrochloric acid (2 mol·L−1), temperature (80 °C) and time (30 min). The proposed method avoids organic solvents such as methanol and acetonitrile commonly used as extraction solvent and/or mobile phase in studies on bioactive compounds in plant-based matrices by high-performance liquid chromatography, thus contributing to lower environmental impact. The validated CE-DAD method was applied to 42 samples of edible mushrooms, including the species Agaricus bisporus (white button mushroom and brown portobello), Lentinula edodes (shiitake), Pleurotus ostreatus (white oyster mushroom, hiratake and shimeji) and Pleurotus ostreatoroseus (pink oyster mushroom). The phenolic compounds homogentisic acid, cinnamic acid and p-coumaric acid were detected in the samples harvested in two seasons – summer and winter - with cinnamic acid reported as the major compound (levels between 53.88 and 440.42 mg·kg−1). Therefore, edible mushrooms have proved to be an alternative source of phenolic compounds.

Polar extracts of extra-virgin olive oils (EVOO) contain a large number of phenolic compounds with antioxidant properties. The antioxidant capacity can be measured by different reaction mechanisms, as the single electron transfer (SET) or the hydrogen atom transfer (HAT). In this work, the total phenolic content (TPC) by the Folin-Ciocalteu method and its correlation with four antioxidant capacity assays (FRAP, ABTS, DPPH• and ORAC) were evaluated for EVOO polar extracts. It was observed that the higher the total phenolic compounds in the EVOO extracts, the higher the antioxidant capacities, regardless of the method employed. The reaction mechanism observed for TPC by Folin-Ciocalteu method and also for FRAP, ABTS and DPPH• antioxidant capacity assays is a single electron transfer, thus, a high correlation among their results is expected. However, the correlation between TPC and ORAC results was also high and significant, allowing to conclude that EVOO phenolic compounds are able to react by the hydrogen atom transfer mechanism, which indicates that they can act as effective radical chain-breaking antioxidants. These results suggest that, for the EVOO polar extracts, TPC by Folin-Ciocalteu and ORAC assays could be sufficient to evaluate their in vitro antioxidant capacity.

Consumption of virgin olive oil (VOO) is highly recommended due to its human health benefits. Brazil is now beginning to experimentally produce VOO, and there are no data on its chemical profile. The aim of this work was to determine the phenolic compound, tocopherol and fatty acid contents of 17 monovarietal VOOs produced from olive varieties cultivated in the southeast region of Brazil during two crop years. The chemical composition of Brazilian VOO resembles that found in the literature for well-established VOOs. The analyzed compounds comprised palmitic acid (6–12%), stearic acid (1.6–2.2%), oleic acid (70–84%), linoleic acid (3.2–11.7%), α-linolenic acid (0.6–1.4%), tyrosol (NQ–155 mg kg − 1 ), (+)-pinoresinol (2.9–23 mg kg − 1 ), hydroxytyrosol (ND–38 mg kg − 1 ), luteolin (ND–2.2 mg kg − 1 ), α-tocopherol (29–233 mg kg − 1 ), β-tocopherol (ND–9.6 mg kg − 1 ), and γ-tocopherol (ND—19 mg kg − 1 ). There was a significant difference in the contents of almost all of the analyzed compounds between the two crop years. Principal component analysis demonstrated that some varieties can be differentiated from one another by chemical composition. The results indicated that some Brazilian monovarietal VOOs are promising and that further studies will help to improve the quality of Brazilian VOO.

Orientadores: Helena Teixeira Godoy, Adriana Dillenburg Meinhart Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos Resumo: Dentre as propriedades funcionais apresentadas pelos cogumelos, destacam-se as propriedades antioxidantes. A principal classe de compostos que colaboram com a atividade antioxidante são os compostos fenólicos. Alguns trabalhos já relataram a presença de compostos fenólicos em diversas espécies de cogumelos, porém estudos que avaliam o perfil dos compostos fenólicos em cogumelos comestíveis cultivados no Brasil são muito escassos. O objetivo desse trabalho foi identificar e quantificar os compostos fenólicos presentes em 4 espécies de cogumelos comestíveis (Agaricus bisporus, Pleurotus ostreatus, Pleurotus ostreatoroseus e Lentinula edodes) produzidas no Brasil, portanto foi desenvolvida uma metodologia de análise por eletroforese capilar através da otimização univariada do pH e análise da curva de mobilidade dos compostos fenólicos. Foi possível separar 11 compostos fenólicos já relatados em cogumelos. O método utilizou os seguintes parâmetros: 175 mmol.L-1 de ácido bórico, pH 8,5, 25°C, 30 kV, capilar 50 µm x 72 cm injeção de 50 mbar durante 5 segundos e detecção em 210 nm, em um tempo de corrida de 21 minutos. Foi realizado um estudo multivariado, utilizando-se um planejamento composto central (otimizando a concentração de ácido clorídrico, tempo e temperatura de extração) para a otimização da extração e hidrólise ácida dos compostos fenólicos presentes na matriz. A condição ótima de extração e hidrólise foi obtida analisando-se 0,3 g de amostra, com 6 mL de ácido clorídrico a 2 mol.L-1, sob refluxo a 79,9°C por 30 minutos. Dentre os compostos investigados, foram identificados e quantificados os ácidos homogentísico, p-cumárico e cinâmico, com predominância do último. O teor de ácido homogentísico variou entre 169,85 e 388,6, p-coumárico entre 25,97 e 103,32 e ácido cinâmico entre 23,38 e 454,07, todos em mg.kg-1 de amostra liofilizada. Foi possível visualizar diferença no perfil dos compostos fenólicos de cogumelos de diferentes variedades. O tipo de substrato no qual os cogumelos são cultivados também foi significativo para os resultados. Da mesma forma, foi possível identificar diferenças em amostras com diferentes graus de maturação Abstract: Among the celebrated functional properties of mushrooms, it calls the attention their antioxidant properties. Antioxidant compounds of the mushrooms are mailing the phenolic compounds. Some studies have reported the presence of phenolic compounds in several species of mushrooms, but studies that evaluate the phenolic content in edible mushrooms grown in Brazil are scarce. The aim of this study was to identify and measure phenolic compounds present in four species of edible mushrooms (Agaricus bisporus, Pleurotus ostreatus, Lentinula edodes and Pleurotus ostreatoroseus) cultivated in Brazil. A methodology of analysis was developed using capillary electrophoresis with pH univariate optimization and analysis of the mobility curve of phenolic compounds, separating 11 phenolic compounds already described in the literature. The following conditions were determinated: 175 mmol.L-1 of boric acid, pH 8.5, 25°C, 30 kV, capillary of 50 µm x 72 with an injection of 50 mbar for 5 seconds and detection at 210nm, at a running time of 21 minutes. A multivariate study was conducted for the optimization of extraction and acid hydrolysis of phenolic compounds present in pattern. It was used a central composite design (optimizing the concentration of hydrochloric acid and extraction time and temperature). It was determined that the optimum condition for extraction and hydrolysis was samples of 0.3 g, 6 mL of hydrochloric acid at 2 mol.l-1 under reflux at 79.9°C for 30 minutes. Among other compounds investigated, homogentisic, p-coumaric and cinnamic acids were identified and quantified, with predominance of the last one. Homogentisic acid content varied from 169.85 to 388.6; p-coumaric acid from 25.97 to 103.32 and cinnamic acid from 23.38 to 454.07, in mg.kg-1 of lyophilized sample. Differences in phenolic content were observed for different varieties of mushrooms, type of substrate on which the mushrooms were grown and stage of maturity Mestrado Ciência de Alimentos Mestre em Ciência de Alimentos

In Brazil, the consumption of extra-virgin olive oil (EVOO) is increasing annually, but there are no experimental studies concerning the phenolic compound contents of commercial EVOO. The aim of this work was to optimise the separation of 17 phenolic compounds already detected in EVOO. A Doehlert matrix experimental design was used, evaluating the effects of pH and electrolyte concentration. Resolution, runtime and migration time relative standard deviation values were evaluated. Derringer's desirability function was used to simultaneously optimise all 37 responses. The 17 peaks were separated in 19min using a fused-silica capillary (50μm internal diameter, 72cm of effective length) with an extended light path and 101.3mmolL(-1) of boric acid electrolyte (pH 9.15, 30kV). The method was validated and applied to 15 EVOO samples found in Brazilian supermarkets.

Methylparaben (MePa), ethylparaben (EtPa) and propylparaben (PrPa) have been widely used, among others, as chemical preservatives in cosmetics, drugs and foods. As these compounds are linked with allergies, dermatitis and estrogenic properties, it is necessary to control the concentration of these substances in different matrices. The aim of this paper are: to evaluate the electrochemical behavior of parabens on the boron-doped diamond (BDD) electrode and the development of a chromatographic method, with electrochemical detection (HPLC-ED), for determination of parabens in shampoo. A BDD (8000 ppm) electrode was adapted in a thin layer mode analytical cell consisting of a stainless steel and a platinum wire as reference and auxiliary electrodes, respectively. Chromatographic separations were obtained with a reversed phase C8 analytical column and a mobile phase of 0.025 molL(-1) disodium phosphate, pH 7.0, and acetonitrile (40:60, v/v), delivered at a flow rate of 1.0 mL min(-1). Sample preparation was performed by solid phase extraction using C18 cartridges and acetonitrile for elution. Benzylparaben was employed as internal standard. The HPLC-ED method developed, using the BDD electrode, was validated for the determination of parabens in shampoos and presented adequate linearity (>0.999), in the range of 0.0125-0.500% (w/w), detectability 0.01% (w/w), precision (RSD of 2.3-9.8%) and accuracy (93.1-104.4%) and could be applied for routine quality control of shampoos containing MePa, EtPa and PrPa.