Evaluation of two brazilian native yeast strains (Pichia kudriavzevii) in craft beer

Samara Teodoro Dos Santos,Marcelo Fossa Da Paz,Ângela Dulce Cavenaghi Altemio

doi:10.33448/rsd-v11i1.24783

Samara Teodoro Dos Santos, Marcelo Fossa Da Paz + Show 1 more

Open Access

https://doi.org/10.33448/rsd-v11i1.24783

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Abstract

Beer production is an ancient biotechnological process and since yeast as discovered to be responsible for the transformation of barley wort into beer, studies have been carried out with the aim of understanding the behavior of these microorganisms. This work aimed to study the application of two strains of yeasts of the species Pichia kudriavzevii, isolated in the Brazilian Midwest for the production of craft beer and to analyze the occurrence of bioaromatization, with the production of volatile organic compounds (VOC) and to evaluate the sensory perception of the results with untrained end consumers through a quick sensory methodology called Check All That Apply (CATA). For this purpose, three batches of beer were produced and inoculated with commercial yeast (Saccharomyces cerevisiae, the control) and two strains of the same species, called Pichia kudriavzevii BB1 and Pichia kudriavzevii BB2. A total of 28 volatile organic compounds that differentiated the control of the Pichia BB1/BB2 group were detected, being 20 esters, 2 alcohols, 5 carboxylic acids and 1 hydrocarbon. There was no difference among the Pichia kudriavzevii BB1 and BB2 samples (p>0.05) in the sensory analysis using the CATA methodology. It was possible to distinguish two clusters between the tasters according to the habit of consuming craft beer, and those who consumed frequently, assigned a higher score in the hedonic test. It was concluded that Pichia kudriavzevii BB1 and BB2 influenced the beer bioaromatization, improving the acceptance test score with the tasters.

Highlights

The production of beer is one of the oldest human activities
It was only relatively recently that the fermentative and biotechnological process was elucidated, and it was understood that the enzymes present in malted cereals degrade starches into soluble sugars, which give rise to a watery sugar extract that will later be transformed by yeasts into alcohol and carbon dioxide (Steensels & Vertstrepen, 2014)
2.1 Strains Origin The two pure strains of the Pichia kudriavzevii species, named respectively BB1 and BB2, were obtained from the Barrálcool Usine, located in the municipality of Barra do Bugres, in the state of Mato Grosso, Brazil. They were isolated by Silva et al (2011) and physiologically described by Camargo et al (2018), who transferred them to the Yeast Storage Bank in the Bioengineering Laboratory from the Universidade Federal de Grandes Dourados (UFGD), in Mato Grosso, Brazil, from where they were thawed

Summary

Introduction

The production of beer is one of the oldest human activities. Hops are responsible for bitterness and characteristic aroma compounds, while yeast produces alcohol, carbonation and hundreds of methabolic by-products (Callaway, 2016), which are complex and play an important role in aroma, and in beer flavor. They impact in the quality of the final product, with the formation of a large amount of volatile compounds belonging to a variety of groups, such as estera, alcohols, acids, aldehydes, ketones, hydrocarbons, sulfuric compounds, heterocyclic compounds. The concentration, synergistic or antagonistic interactions between these substances influence the aroma and flavor of beer (Riu-Aumatell et al, 2014)

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