title: Determination of free fatty acids in beer wort.
abstract: The importance of free fatty acids (FFAs) in wort has been known for a long time because of their influence on beer quality and yeast metabolism. Lipids have a beneficial effect on yeast growth during fermentation as well as negative effects on beer quality. Lipids content of beer affects the ability to form a stable head of foam and plays an important role in beer staling. Moreover, the ratio of unsaturated and saturated fatty acids seems to be related to gushing problems. A novel, simple, and reliable procedure for quantitative analysis of FFAs in wort was developed and validated. The determination of FFAs in wort was achieved via liquid-liquid cartridge extraction, purification of FFA fraction by solid phase extraction, boron trifluoride in methanol methylation, and injection into GC-FID system. The proposed method has high accuracy (<0.3%, expressed as the bias), high precision (<1.2%, RSD), and recoveries ranging from 74% to 98%. The method was tested on two different wort samples (9° and 12° Plato).
authors.affiliation: Department of Economic and Food Sciences, Section of Food Technology and Biotechnology, University of Perugia, Via S. Costanzo n.c.n., 06126 Perugia, Italy. Electronic address: e.bravi@unipg.it.
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Bravi
authors.affiliation: Department of Economic and Food Sciences, Section of Food Technology and Biotechnology, University of Perugia, Via S. Costanzo n.c.n., 06126 Perugia, Italy.
authors.forename: Paolo
authors.initials: P
authors.lastname: Benedetti
authors.affiliation: Italian Brewing Research Center, Centro di Eccellenza per la Ricerca sulla Birra - CERB, University of Perugia, Via S. Costanzo n.c.n., 06126 Perugia, Italy.
authors.forename: Ombretta
authors.initials: O
authors.lastname: Marconi
authors.affiliation: Italian Brewing Research Center, Centro di Eccellenza per la Ricerca sulla Birra - CERB, University of Perugia, Via S. Costanzo n.c.n., 06126 Perugia, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Perretti
mesh_terms: D001515:Beer / Q000032:analysis*; D005230:Fatty Acids, Nonesterified / Q000737:chemistry*; D005285:Fermentation; D008055:Lipids / Q000032:analysis*; D059625:Liquid-Liquid Extraction / Q000379:methods*; D052616:Solid Phase Extraction / Q000379:methods*
chemical_list: D005230:Fatty Acids, Nonesterified; D008055:Lipids
keywords: Beer wort; Free fatty acids; Liquid–liquid cartridge extraction; Solid phase extraction