Mônica Cristiane Rojo de Camargo

Polycyclic aromatic hydrocarbons in Brazilian vegetables and fruits

Abstract Polycyclic aromatic hydrocarbons (PAHs) occur as contaminants in different types of food predominantly from environmental pollution, food packaging and food processing and the levels found depend on the source of the contamination. PAHs emissions from automobile traffic and industry activities were shown to influence the PAHs levels and profiles in vegetables and fruits grown nearby. The present study was carried out to determine the levels of PAHs in samples of lettuce, tomato, cabbage, apple, grape and pear, and use these data to further estimate the dietary exposure of Brazilians to PAHs. Samples of each fruit and vegetable were collected in six different places and analysed for ten PAHs. The analytical method involved saponification with methanolic KOH, liquid–liquid extraction with cyclohexane, clean-up on silica gel column and determination by high performance liquid chromatography using fluorescence detection. The mean levels of total PAHs were 13.53 μg/kg in lettuce, 9.50 μg/kg in tomato, 8.86 μg/kg in cabbage, 4.05 μg/kg in apple, 3.77 μg/kg in grape and 3.87 μg/kg in pear. Of the carcinogenic PAHs, benzo(a)anthracene was the most representative, being found in 89% of all samples analysed. Chrysene was not detected in any sample.

Evaluation of polycyclic aromatic hydrocarbons content in different stages of soybean oils processing

A study was conducted in order to determine the levels of 13 polycyclic aromatic hydrocarbons (PAHs) in crude soybean oils produced in Brazil and to evaluate the influence of the refining process in their reduction. Analysis of intermediary products (neutralized, bleached and deodorized oils) showed that all compounds were reduced through refining (up to 88%). Neutralization and deodorization steps contributed effectively to the PAHs decrease. The mean total PAHs content in crude and deodorized oil samples ranged, respectively, from 10 to 316 and 3 to 69μg/kg. Since vegetable oils have been shown to be the major sources of PAHs in the diet, a monitoring program should be developed by the refining industries and the use of activated carbon during oil processing is highly recommended.

Chá-mate e café como fontes de hidrocarbonetos policíclicos aromáticos (HPAs) na dieta da população de Campinas

In order to estimate the contribution of mate tea and regular coffee as a source of PAHs in the diet of the population of Campinas, SP, Brazil, different batches and brands of these products, totaling 18 samples, were analysed for PAH. The consumption data were obtained from a dietary survey (frequency recall), which took place in Campinas in 1993. PAH levels in the products were determined by high performance liquid chromatography with fluorescence detection. Different PAHs were detected in all samples of coffee, at levels varying with the brands and the beverage preparation technique. The mean total PAH content in coffee was 10.12mg/kg, while mate tea showed a relatively lower level of contamination (S=0.70mg/kg). Considering the per capita average daily consumption estimates of 69.79g of mate tea and 86.77g of coffee, one can assume that mate tea and coffee contribute with approximately 0.05mg and 0.88mg of total PAHs, respectively, to the dietary intake of these contaminants by the studied population (n=600).

HPLC determination of caffeine in tea, chocolate products and carbonated beverages

Different brands of mate and black tea, chocolate products and carbonated beverages available on the Brazilian market were analysed for caffeine by high-performance liquid chromatography with a UV-vis detector at 254 nm. The column was a reverse phase C18 and the mobile phase consisted of methanol–water (30:70, v/v), acetonitrile–water (10:90, v/v) and methanol–water (25:75, v/v) for tea, chocolate products and soft drinks respectively. Caffeine content ranged from 1.05 to 15.83 mg per cup in mate tea, from 32.21 to 36.23 mg per cup in black tea, from 0.14 to 0.95 mg g−1 in chocolate products from 2.73 to 7.49 mg per can in guarana-type soft drinks and from 19.81 to 45.89 mg per can in cola soft drinks. These data indicate that the levels of caffeine in Brazilian teas, chocolates and soft drinks are within the ranges reported for similar products in other countries. © 1999 Society of Chemical Industry

Contribuição do guaraná em pó (Paullinia cupana) como fonte de cafeína na dieta

OBJECTIVE: The present study was conducted in order to determine the caffeine levels in different brands of commercially available guarana powder. METHODS: The analytical methodology involved extraction with water, clean-up with saturated basic lead acetate solution and determination by high performance liquid chromatography with diode array detector (200-400nm). 39 samples were purchased in the cities of Campinas and Ribeirao Preto, SP, between December 2003 and January 2004 and analyzed. RESULTS: The caffeine levels in the samples varied widely ranging from 9.52 to 36.71mg/g, probably due to differences in the origin of the raw material and to the types of processing that the guarana seeds are submitted to. In comparison to coffee, traditional source of caffeine in the diet, it is possible to verify that the average caffeine content in guarana powder is about four times higher than the quantities present in coffee. CONCLUSION: Among guarana powder consumers, this product may be considered as an important source of caffeine in the diet. The association with other products containing caffeine suggests that the guarana powder consumption should be controlled as the debate regarding caffeines safe dose of intake remains.

Determinação de hidrocarbonetos policíclicos aromáticos (HPAS) em guaraná em pó (Paullinia cupana)

Hidrocarbonetos policiclicos aromaticos (HPAs) representam uma importante classe de carcinogenos quimicos formados durante a combustao incompleta de material orgânico. Os HPAs ocorrem como contaminantes em diferentes tipos de alimentos, devido principalmente a poluicao ambiental e alguns tipos de processamentos como a defumacao, a secagem e a torrefacao. Nos ultimos anos, o consumo de guarana vem aumentando, assim como a sua oferta no mercado. Durante o processamento das sementes para a obtencao dos produtos, a materia-prima passa pelas etapas de secagem, torrefacao e, em alguns casos, a defumacao, processos estes que podem dar origem aos HPAs. Dessa forma, o presente estudo foi conduzido com o objetivo de avaliar a presenca de cinco HPAs carcinogenicos: benzo(a)antraceno, benzo(b)fluoranteno, benzo(k)fluoranteno, benzo(a)pireno e dibenzo(a,h)antraceno em diferentes marcas de guarana em po disponiveis comercialmente. A determinacao foi feita por Cromatografia Liquida de Alta Eficiencia com Deteccao por Fluorescencia. Os HPAs foram detectados em 81% das amostras analisadas, com niveis variando de 0,05 a 8,04 µg/kg. Os resultados indicam que o tipo de processamento utilizado durante a manufatura do guarana em po pode resultar na presenca desses contaminantes no produto final.

HPLC-FLD simultaneous determination of 13 polycyclic aromatic hydrocarbons: validation of an analytical procedure for soybean oils

. A method using high performance liquid chromatography with fluorescence detection (HPLC-FLD) was developed for the simultaneous determination of 13 polycyclic aromatic hydrocarbons (PAHs) in soybean oils. The sample preparation includes liquid-liquid extraction with dimethylformamide-water (9:1, v/v) followed by a clean-up and concentration step with C-18 SPE cartridges. The method showed good recoveries for most of the PAHs studied with values between 71 and 115%. The calibration curves were linear over the range tested (R 2 > 0.999). Detection and quantification limits varied between 0.02-0.76 µg kg -1 and 0.03-0.96 µg kg -1 , respectively. The analytical procedure was successfully applied to evaluate the contamination of most consumed brands of soybean oils commercially available in the Brazilian market. The presence of PAHs was confirmed in all samples analyzed with mean values ranging from 0.20 to 5.93 µg kg -1 .

Determinação de benzo(a)pireno em pescados

In the present study samples of fresh and processed fish, shrimp, mussels and crab meat commercialized in the metropolitan area of Campinas (SP), Brazil were analysed for benzo(a)pyrene (B(a)P). The methodology involved extraction with n-hexane, clean-up on Sep-Pak silica plus and determination by High Performance Liquid Chromatography with a Fluorescence Detector. B(a)P was detected in all samples analysed (n=35) at levels ranging from to 0.03 a 4.54 µg/kg. The highest content of B(a)P was found in smoked products (mean level=2.5 µg/kg ) and mussels (mean level=2.4 µg/kg). In view of the carcinogenic potential of this widely distributed contaminant and the importance of seafood in the daily diet of fisherman communities, a monitoring program should be initiated to identify and control the source of contamination of seafood by B(a)P.

Polycyclic Aromatic Hydrocarbons

Carbonaceous materials play an important role in space. Polycyclic Aromatic Hydrocarbons (PAHs) are a ubiquitous component of the carbonaceous materials. PAHs are the best-known candidates to account for the IR emission bands. They are also thought to be among the carriers of the diffuse interstellar absorption bands (DIBs). PAH ionization states reflect the ionization balance of the medium while PAH size, composition, and structure reflect the energetic and chemical history of the medium. A major challenge is to reproduce in the laboratory the physical conditions that exist in the emission and absorption interstellar zones. The harsh physical conditions of the ISM -low temperature, collisionless, strong UV radiation fields- are simulated in the laboratory by associating a molecular beam with an ionizing discharge to generate a cold plasma expansion. PAH ions and radicals are formed from the neutral precursors in an isolated environment at low temperature and probed with high-sensitivity cavity ringdown spectroscopy in the NUV-NIR range. Carbon nanoparticles are also formed during the short residence time of the precursors in the plasma and are characterized with time-of-flight mass spectrometry. These experiments provide unique information on the spectra of large carbonaceous molecules and ions in the gas phase that can now be directly compared to interstellar and circumstellar observations (IR emission bands, DIBs, extinction curve). These findings also hold great potential for understanding the formation process of interstellar carbonaceous grains. We will review recent progress in the experimental and theoretical studies of PAHs, compare the laboratory data with astronomical observations and discuss the global implications.