Free Fatty Acid Determination in Alcoholic and Non-Alcoholic Beers via Liquid Chromatography–High-Resolution Mass Spectrometry Analysis

In recent years, non-alcoholic beers have been gaining popularity. Among the various components that affect the flavor and sensory characteristics of beers, free fatty acids (FFAs) are minor components. However, due to their involvement in beer quality, fast and simple methods for analyzing FFAs in beers are of importance. In this work, we present a liquid chromatography–high-resolution mass spectrometry (LC-HRMS) method for the rapid determination of FFAs in beers, avoiding a tedious sample preparation and derivatization and allowing the simultaneous study of a large set of FAs, including medium-chain, long-chain, saturated, monounsaturated and polyunsaturated FAs. The method was applied in the analysis of twelve non-alcoholic and nine alcoholic beer samples from the local market, permitting the comparison of their FFA profiling. Among the 37 FAs studied, 29 were quantified, and palmitic, stearic, oleic and myristic acids were identified as the predominant FAs in both alcoholic and non-alcoholic beers. The majority of the predominant long-chain FAs, including palmitic, stearic and myristic acids, were found in decreased amounts in non-alcoholic beers, compared to the alcoholic ones, with the marked exception of oleic acid, which was increased in non-alcoholic beers. Among the medium-chain FAs, octanoic acid was found at lower concentrations in non-alcoholic beers, comparing to regular beers, while lauric acid was slightly increased. Principal component analysis (PCA) suggested the correlation of FFAs with the type of beer (alcoholic or non-alcoholic beer).