There are numerous scientiﬁc publications about the folate content of several types of beers available in commercial trade, in these it has been reported that beer can be a valuable source of folate depending on beer type, but a huge deviation is observed between the diﬀerent products. There is lack of information about the eﬀect of raw materials and technological steps of brewing on folate content that could be helpful to understand the evolution of folate during the brewing process and to get a deeper insight into what makes the folate content of each product so diﬀerent.
Folate belongs to the vitamin B family. It serves as an essential coenzyme in one carbon metabolism, principally as acceptor and donor of one-carbon units. Through this role, folate coenzymes mediate the metabolism of nucleic and amino acids, and thus ﬁll an important function in purine and pyrimidine metabolism and the remethylation of homocysteine to methionine. Methionine is the immediate precursor of S-adenosyl methionine, which functions as the universal donor in many transmethylation reactions, including the methylation of DNA, histones, and other proteins. Thus, folate deﬁciency can lead to severe metabolic and clinical consequences (Pitkin, 2007; Moll & Davis, 2017).
Folate occurs in natural foods as several vitamers, reduced derivatives of folic acid (pteroyl-L-glutamic acid), which mainly exist as polyglutamates. Folic acid, which is a monoglutamate, is the oxidised and most active form of the vitamin found rarely in food, it is the form used in vitamin preparations and food fortiﬁcation (Andersson et al., 2008).
Methods to quantify folates in food samples are complicated due to the numerous forms of native folates, their instability, the complexity and variety of food matrices, and the relatively low concentration of the analytes (Arcot & Smrestma, 2005). In this study the microbiological assay was applied, because it is suitable for the determination of total folate content, does not require sophisticated instrumentation, is relatively economical, and has high sensitivity (Preirrer et al., 2010).
There are several publications about the folate content of beers originating from diﬀerent countries of the world. Póo-Prieto and co-workers (2011) investigated the folate content of Spanish beers, which ranged between 1.6 and 2.6 μg/100 ml. Walker and co-workers (2003) reported values for total folate in Bavarian wheat beers ranging from 4.7 to 12.5 μg/100 ml. Pietercelie and co-workers (2003) claimed that 14% of refermented Belgian beers contained more than 20 μg/100 ml, while Bertuzzi and co-workers (2020) reported the folate content of 80 beers (40 small-scale, 40 large-scale) available in Italy ranging between 1.55 and 10.48 μg/100 ml. Based on these results, it is hard to draw conclusions about the general folate content of beer, but the study of brewing technology can help to understand the diﬀerences.
The folate content of beer originates from two main sources: grains and yeasts. As more than 90% of commercial beers are ﬁltered, the grain is the primary source of folate in the majority of the ﬁnal products. The most often used cereal for beer brewing is barley, but wheat, oat, and rye are also applied besides barley. Grains used for brewing are mainly used in their malted form. The malting process consists of three main stages: steeping, germination, and kilning. Germination has been reported as a way to improve folate content in wheat (Koemler et al., 2007), barley (Walker et al., 2002), oats (Wilmelmson et al., 2001), and rye (Liukkonen et al., 2003).
Beer brewing is a biotechnological process during which, with the help of the enzymes of malted cereals (mainly barley), the micro and macro nutrients of the malt are dissolved in water (mashing), then separated from the water insoluble particles (wort separation, ﬁltration), boiled with hops (hop boiling), then the precipitated protein-polyphenol complexes and hop residues are separated in the whirlpool, afterwards the liquid (hopped wort) is cooled down and inoculated with brewer’s yeast. In this research the eﬀect of mashing, wort separation, hop boiling, and whirlpool were studied.
There is only one publication about the study of the folate content during some technological steps of brewing, as mashing, fermentation, and packaging, in pilot and commercial scale breweries (Jäuerstad et al., 2005). But this article does not provide any information about the technological parameters (temperature, time, volume, facilities, and so on), furthermore does not provide concrete concentrations of folate content, it reports the results in the dimension of folate content relative to barley. In order to draw concrete conclusions, it is necessary to know the technological parameters and facilities accurately. In this study the aim was to investigate diﬀerent raw materials and the evolution of folate content in laboratory and pilot scale brewing with the detailed description of the technological parameters.
This research project was supported by the Doctoral School of Food Sciences of Szent István University (SZIU).
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)| false . ( ., Walker, C.J . & Smitm, R Livens, S 2003): The folate (vitamin B9) content of commercially available malted products and co-products.-in: Walker, C.J.: The folate content of malted products: Strategies for improvement. HGCA Project Report 321, pp. 11– 22.
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)| false . ( ., Wilmelmson, A ., Oksman‐Caldentey, K.M ., Laitila, A ., Suortti, T . & Kaukovirta‐Norja, A Poutanen, K 2001): Development of a germination process for producing high β‐glucan, whole grain food ingredients from oat. Cereal Chem., 78( 6), 715– 720. 10.1094/CCHEM.2001.78.6.715