Enhancing the levels of 4-vinylguaiacol and 4-vinylphenol in pilot-scale top-fermented wheat beers by response surface methodology

Abstract

Top-fermented wheat beers are desired by consumers because of their distinctive clove-like and phenolic aroma, in which two characteristic flavour substances, 4-vinylguaiacol (4VG) and 4-vinylphenol (4VP), are of vital importance. In this paper, the levels of 4VG and 4VP were the subject of an intensive and detailed investigation. The influence of wheat malt proportion, mashing-in temperature, boiling time and fermentation temperature on 4VG and 4VP was studied by pilot-scale brewing experiments using a 10 hL mashing vessel and 20 hL fermentation tanks. Response surface methodology (RSM) was used to explore the possibilities for enhancing the concentration of 4VG and 4VP in top-fermented wheat beers. Statistical analysis of the results showed that for the ranges of wheat malt proportion studied, mashing-in temperature, boiling time and fermentation temperature all had a significant influence (p <0.05) on 4VG and 4VP production. Based on the response surface plots, the optimal brewing parameters that maximized 4VG and 4VP levels were as follows: (a) wheat malt proportion 40%; (b) mashing-in temperature 44°C; (c) boiling time 88 min; and (d) fermentation temperature 19.5°C, resulting in significantly increased levels of 4VG and 4VP (2.418 mg/L and 1.402 mg/L, respectively). These brewing and fermentation parameters were concluded to be the optimal conditions to highlight the typical flavour and aroma of top-fermented wheat beers.

Physiology, ecology and industrial applications of aroma formation in yeast

“…Other fermentation parameters, such as temperature and carbon source, have been shown to affect formation of phenolic compounds, but the underlying mechanisms are not understood (Vanbeneden 2007 ; Cui et al. 2015 ).…”

A preliminary study of the quality attributes of a cloudy wheat beer treated by flash pasteurization

“…The levels of 4‐VG in wheat beer samples were determined by high‐performance liquid chromatography (HPLC) with an accuracy and precision of 0.001 mg/L . The HPLC system consisted of a separation module (model 2695) equipped with a photodiode array detector (model 2996, Waters Corp. USA).…”

“…Although top‐fermented wheat beer is not considered a traditional product, the sales over the years in wheat beer have soared in the Chinese market. Wheat beer is brewed with barley malt and malted or unmalted wheat, where the percentage of wheat typically has to be at least 40% of the grist bill . It is characterized as a beer, with a unique fine and smooth foam, a fruity/banana‐like and clove‐like aroma, a full mouthfeel and less hoppy bitterness .…”

Shelf-life studies of flavour characteristics in model UHT liquid systems enriched with wholegrain oat

“…Of the numerous phenolic acids in oats, the primary one is ferulic acid ( Hitayezu et al., 2015 ). Ferulic acid decarboxylation produces 2-methoxy-4-vinylphenol (PVG), which is an off-flavour compound in various foods, including beer ( Cui et al., 2015 ), due to a clove or spice-like aroma. PVG's threshold varies with food matrices: 0.3 mg/L in beer ( Cui et al., 2015 ) and 0.1 mg/L in water ( Belitz et al., 2009 ).…”