| Title: | Matrix-compatible solid phase microextraction coating improves quantitative analysis of volatile profile throughout brewing stages |
| Author(s): | Hernandes KC; Souza-Silva EA; Assumpcao CF; Zini CA; Welke JE; |
| Address: | "Instituto de Ciencia e Tecnologia de Alimentos (ICTA), Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Goncalves, 9500, Predio 43212, Porto Alegre CEP 91501-970, Brazil. Instituto de Quimica (IQ), Departamento de Quimica Inorganica (DQI), UFRGS, Av. Bento Goncalves, 9500, Porto Alegre, RS CEP 91501-970, Brazil; Departamento de Quimica, Instituto de Ciencias Ambientais, Quimicas e Farmaceuticas, Universidade Federal de Sao Paulo (UNIFESP), Rua Prof. Artur Riedel, no 275, Diadema, SP CEP: 09972-270, Brazil. Instituto de Quimica (IQ), Departamento de Quimica Inorganica (DQI), UFRGS, Av. Bento Goncalves, 9500, Porto Alegre, RS CEP 91501-970, Brazil. Instituto de Ciencia e Tecnologia de Alimentos (ICTA), Universidade Federal do Rio Grande do Sul (UFRGS), Av. Bento Goncalves, 9500, Predio 43212, Porto Alegre CEP 91501-970, Brazil. Electronic address: juliane.welke@ufrgs.br" |
| DOI: | 10.1016/j.foodres.2019.04.048 |
| ISSN/ISBN: | 1873-7145 (Electronic) 0963-9969 (Linking) |
| Abstract: | "Ethanol is the major matrix constituent of beer and has been reported as an important interfering volatile during headspace solid phase microextraction (HS-SPME) of minor compounds due to its displacement effect. The addition of a thin hydrophobic polydimethylsiloxane (PDMS) layer on a commercial divinylbenzene/Carboxen/PDMS (DVB/Car/PDMS) fiber was evaluated, for the first time, to minimize the displacement effect caused by ethanol in the quantitative determination of volatile profile of five stages of brewing. Analysis were performed through gas chromatography coupled to mass spectrometry detector. The extractive capacity of the PDMS-overcoated fiber was superior to the commercial analogous fiber, since the modified version extracted a greater number of compounds (61 versus 45) and allowed to obtain 20% more of total chromatographic area than the commercial fiber. The ethanol content of model solutions (0, 4, 8 and 12%) did not result in significant differences in responses neither to polar nor to medium polar or nonpolar analytes when PDMS-overcoated fiber was used. On the other hand, a displacement effect was observed when polar compounds were extracted by the commercial fiber. There was no need to prepare different analytical curves with distinct ethanol levels close to those found in each brewing stage, when PDMS-overcoated fiber was used. This approach turns the analytical method simpler, less laborious and time consuming. It showed adequate linearity, sensitivity, repeatability and intermediate precision. A heat map displayed the quantitative differences in the volatile profile of each stage of brewing. Mashing stood out in relation to the others steps by the highest levels of higher alcohols. Boiling was characterized by the highest levels of Maillard reaction products, while fermentation, maturation and pasteurization were discriminated by a major presence of esters. Terpenes were incorporated to the wort during boiling or fermentation and the concentration of these compounds remained similar throughout the subsequent brewing steps" |
| Keywords: | Dimethylpolysiloxanes/chemistry Esters/analysis Evaluation Studies as Topic *Food Handling Gas Chromatography-Mass Spectrometry Polyvinyls/chemistry *Solid Phase Microextraction Terpenes/analysis Volatile Organic Compounds/*analysis Aroma Beer DVB/Car/PDM; |
| Notes: | "MedlineHernandes, Karolina C Souza-Silva, Erica A Assumpcao, Carolina F Zini, Claudia A Welke, Juliane E eng Research Support, Non-U.S. Gov't Canada 2019/07/10 Food Res Int. 2019 Sep; 123:75-87. doi: 10.1016/j.foodres.2019.04.048. Epub 2019 Apr 22" |
