Ana Maria de Resende Machado

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.

Experimental Design Methodology to Optimize the Solid Phase Microextraction Procedure Prior to GC/MS Determination of Ethyl Carbamate in Samples of Homemade Cachaça

Seeking to improve the quality of cachaça, the Ministério da Agricultura, Pecuária e Abastecimento (Ministry of Agriculture, Livestock and Supply - MAPA), the body responsible for setting and approving regulations governing the Identity and Quality Standards (PIQs) for distilled sugar cane spirits and cachaça, through the Normative Instruction No. 13 of 2005 included some contaminants such as ethyl carbamate (EC), acrolein, lead, and arsenic that must be evaluated in these drinks. Studies on EC, as well as the methods for its determination, are required to evaluate and determine which factors contribute to the formation of this compound in the beverage. An analytical method using gas chromatography/mass spectrometry (GC/MS) with prior sample treatment by solid phase microextraction (SPME) was developed along with the assessment of the principal validation parameters. These two developments lead to the determination of EC with analytical reliability. The optimization of the extraction step was performed via a factorial design involving the selection of parameters such as extraction time, extraction temperature, salt concentration, desorption time, pH, and the method of extraction. The linear range was 5.0 to 200.0 µg L−1 (R2 = 0.9965) with limits of detection and quantification of 1.5 and 5.0 µg L−1, respectively. The recoveries for samples of cachaça containing 10.0 and 80.0 µg L−1 concentrations of EC were 89% and 93%, respectively. The concentrations of EC in the samples of cachaça examined were well below the limits required by Brazilian law.

Use of solid phase microextraction to identify volatile organic compounds in brazilian wines from different grape varieties

The Brazilian wine industry has shown significant growth in recent years and the insertion of new concepts, such as geographical indications as signs of quality, has placed Brazil in tune with the tendencies of world wine production. The aim of this work was to apply the Solid Phase Microextraction technique in combination with Gas Chromatography-Mass Spectrometry to study Brazilian wines made from different grape varieties, in order to separate and identify their volatile organic compounds. These substances were identified by comparisons between the spectra obtained with those presented in the NIST library database, and by comparisons with linear retention indices and literature data. The amounts of the compounds were calculated based on the total peak areas of the chromatograms. Forty-seven volatile compounds were identified and grouped into alcohols, aldehydes, fatty acids, esters, hydrocarbons, ketones and terpenes. Most of them belonged to the ester function, conferring a fruity aroma on the wines. The alcohols may have originated from the yeast metabolism, contributing to the alcoholic and floral aromas. Ethyl lactate, 1-hexanol and diethyl maleate were identified in all the varieties, except Merlot. Decanal, methyl citronellate, (E)-2-hexenyl-3-methylbutyrate were only found in Merlot, while 2,3-butanediol was only present in the Tannat wines. 2-Phenylethanol was present in all varieties and is recognized as giving pleasant rose and honey attributes to wines. This study showed that the volatile profile of red wines is mainly characterized by esters and higher alcohols. The statistical analysis of the comparison of averages showed a greater amount of averages significantly different in the relative areas of Merlot wine. The Principal Component Analysis showed one grouping composed only of the Merlot wine samples, and this was probably related to the existence of the volatile organic compounds that were specifically identified in these wines.

Electrospray Ionization Mass Spectrometry Characterization of Musts and Alembic Brazilian Cachaças Using Selected Yeast Strains

The choice of fermentation system during cachaça production can greatly influence the chemical composition of the beverage. In this work, Saccharomyces cerevisiae strains were selected based on fermentative properties and used as starters to produce alembic cachaça. In distillery scale production, the selected yeast strains exhibited greater adaptiblity to the fermentation environment and hence remained predominant throughout the process. Electrospray ionization mass spectrometry in the negative ion mode revealed that most of the compounds present in the must are different from those formed in the distillate for both cachaças obtained from spontaneous and selected strains. However, beverages produced using selected strains showed greater similarity in chemical profiles than those produced from spontaneous strain fermentation. Moreover, a smaller number of ions were detected in beverages produced by selected strain than from spontaneous strain fermentation. Our results indicate that the selected S. cerevisiae strains evaluated are able to produce cachaças less subject to variation in chemical composition. This could potentially improve brand consistency and thus commercial viability, particularly in the international market.