Production and sensory analysis of grape flavoured beer by co-fermentation of an industrial and a genetically modified laboratory yeast strain

Abstract

The so-called “craft beer revolution” has increased the demand for new styles of beers, often with new ingredients like flavour extracts. In recent years, synthetic biology has realized the production of a plethora of plant secondary metabolites in microbial hosts, which could provide an alternative source for these compounds. In this study, we selected a in situ flavour production approach for grape flavour addition. We used an O-methyl anthranilate (OmANT) producing laboratory Saccharomyces cerevisiae strain in co-fermentations with an industrial beer yeast strain WLP644. The laboratory strain provided an ease of genetic manipulation and the desirable properties of the WLP644 strain were not modified in this approach. In shake flasks, a 10:90 ratio of the yeasts produced grape flavoured beer with the yeast produced flavour compound in a range normally used for flavoured beverages. Hopped and unhopped beers were analysed by VTT’s trained sensory panel and with olfactory GC–MS. OmANT was successfully detected from the beers as a floral odour and flavour. Moreover, no off-flavours were detected and aroma profiles outside the grape flavour were rather similar. These results indicate that the co-fermentation principle is a suitable approach to change the flavour profiles of beers with a simple yeast strain drop-in approach.

Raspberry Ketone Accumulation in Nicotiana benthamiana and Saccharomyces cerevisiae by Expression of Fused Pathway Genes

“…Recently, due to public awareness, there has been an increase in the demand for sustainably produced flavor compounds derived from natural sources . Yeast can be used as a platform for production and extraction of raspberry ketone as a flavor compound but also for adding flavor to fermented beverages . The use of genetically modified yeasts might also become a viable option in the future in Europe.…”

“… 1 Yeast can be used as a platform for production and extraction of raspberry ketone as a flavor compound but also for adding flavor to fermented beverages. 2 The use of genetically modified yeasts might also become a viable option in the future in Europe. Since the approval of the first genetically modified (GM) yeast for food production in USA and Canada two decades ago, 3 GM yeast have been used in enhancing the flavor profile of beer.…”

Sour Beer as Bioreservoir of Novel Craft Ale Yeast Cultures

“…These approaches include hybridization, use of non- S. cerevisiae strains, and bioprospecting for novel wild yeast species and strains from alternative or unusual niches [ 9 , 10 , 11 ]. Recently, genetically modified yeasts have been exploited to boost hop-related flavor-active molecules [ 12 , 13 , 14 , 15 ]. The selection of suitable yeast strains is a crucial step in producing high-quality craft beer that affects both wort fermentation and beer conditioning.…”