Beer Brewing, Applications of Metabolic Engineering

Abstract

Currently, beer is one of the beverage products with the largest annual production worldwide of 1767 million hL in 2007 alone, with lager beer production accounting for 90% of the total beer produced. The present drivers for technological improvement in brewing are increased industrial competition and consolidation, constant demand for increased productivity and flexibility, and the need for achieving high quality together with low costs and compliance with environmental policies. Using metabolic engineering strategies, improvements in the brewer's yeast fermentation performance has involved increased attenuation rate, improved control of the production of beer flavor metabolites, increased ethanol yields and osmotolerance for high‐gravity beer fermentations, and reduced ethanol yield for low or zero alcohol beer production. With the availability of the Saccharomyces cerevisiae genome sequence, together with the bioinformatics tools enabling integration and interrogation of large x‐omics data sets, it is possible to identify high‐probability targeted genetic or metabolic strategies to increase yield, titer, productivity, and/or robustness of the existing brewing process. As the use of GMO strains in brewing is not accepted, mutagenesis remains the alternative approach for obtaining brewer's yeast variants with superior performances. However, the use of enzymes, often products of genetically modified strains, for brewing process optimization is currently recognized. As brewing is a product‐based process, introduction of new technologies for process optimization such as high‐gravity brewing and continuous fermentation using immobilized yeast in brewing lead to improved economics without change in the product characteristics and quality.

Profiling the Volatile and Non-Volatile Compounds along with the Antioxidant Properties of Malted Barley

“…Beer is a complicated combination of ingredients that are fermented from raw material, yeast, malt, and hops, and includes a wide variety of several chemical elements that can act together at all phases of the brewing process [17]. Different groups of composites have been indicated to play a significant role in the flavor properties [18], for example, ketones, higher alcohols, aldehydes, esters, and organic acids, which contribute to the final sensory nature of beer, [19][20][21][22][23][24]. The production of non-alcoholic beer using the thermal process is mostly applied in industry; in this case the beer is degassed and subsequently preheated in a plate heat exchanger.…”

Optimal Design Approach Applied to Headspace GC for the Monitoring of Diacetyl Concentration, Spectrophotometric Assessment of Phenolic Compounds and Antioxidant Potential in Different Fermentation Processes of Barley

“…Some of these by-products are unsuitable because they impart beer off-flavors/aromas [5]. Particularly interesting topics are the reduction of diacetyl, dimethyl sulfide (DMS) or hydrogen sulfide and an enhanced production of sulfur dioxide or esters [6]. They are originated from two amino acids namely valine and leucine, and are responsible for toffee, butterscotch, honey and vanilla-like off-flavors when they are present at concentrations higher than their threshold values (>0.1-0.4 mg/L) [7,8].…”