Contribution of Non- Saccharomyces Yeasts to Wine Freshness. A Review

Abstract

Freshness, although it is a concept difficult to define in wines, can be understood as a combination of different circumstances. Organolepticwise, bluish red, floral and fruity, more acidic and full-bodied wines, are perceived as younger and fresher by consumers. In traditional winemaking processes, these attributes are hard to boost if no other technology or biotechnology is involved. In this regard, the right selection of yeast strains plays an important role in meeting these parameters and obtaining wines with fresher profiles. Another approach in getting fresh wines is through the use of novel non-thermal technologies during winemaking. Herein, the contributions of non-Saccharomyces yeasts and emerging technologies to these parameters are reviewed and discussed.

Keywords: biopolymers; freshness; non-Saccharomyces; sensory quality; wine; yeast metabolites.

Figure 1

Phylogenetic relationships among wine yeast species based on analysis of D1/D2 LSU rRNA gene sequences. The evolutionary history was inferred by using the Maximum Likelihood method based on the Tamura-Nei model in MEGA7. GenBank accession numbers follow strain numbers: Saccharomyces cerevisiae NRRL Y-12632/AY048154; Metschnikowia pulcherrima NRRL Y-7111/U45736 Metschnikowia fructicola B-4(1)/EU441890; Lachancea thermotolerans CBS 2803/KY108273; Torulaspora delbrueckii NRRL Y-866/U72156; Wickerhamomyces anomalus NRRL Y-366/U74592; Pichia kluyveri NRRL Y-11519/U75727; Hanseniaspora uvarum NRRL Y-1614/U84229; Hanseniaspora opuntiae CBS 8733/AJ512453; Hanseniaspora vineae NRRL Y-17529/U84224; Hanseniaspora osmophila NRRL Y-1613/U84228; Hanseniaspora guilliermondii NRRL Y-1625/U84230; Schizosaccharomyces pombe NRRL Y-12796/AY048171; Starmerella bombicola 16-D-2/KF935227; Starmerella bacillaris CBS 1713/KY109779.

Figure 2

Metabolic pathways involved in the formation of floral and fruity esters in yeasts. Production of acetate esters by Ehrlich catabolism of amino acids and production of fatty acids ethyl esters (TA: transaminase, KDC: 2-keto acid decarboxylase, ADH: alcohol dehydrogenase, Atf: acyltransferase). Formation of fatty acid ethyl esters by acylation with acyl-CoA (PDC: pyruvate decarboxylase, ADH: alcohol dehydrogenase, Eeb1/Eht1: ethyl ester biosynthesis/ethanol hexanoyl transferase).

Figure 3

Metabolic pathways involved in the de novo synthesis from sugars of floral esters by H. vineae following the chorismate-prephenate-(S)-mandelate/phenylalanine pathway (ChM: chorismate mutase, PrD: prephenate dehydratase, hmaS: hydroxymandelate synthase, hmO: hydroxymandelate oxidase, bDC: benzoylformate decarboxylase, aDH: benzyl alcohol dehydrogenase; aAT: aromatic aminotransferase; Atf: acyltransferase). Adapted from [36,38,39].

Figure 4

Maloalcoholic fermentation by Schizosaccharomyces pombe and its influence in the subsequent formation of stable vitisin A-type pigments by chemical condensation with grape anthocyanins (adapted from [17,61]).

Figure 5

Example of red wine pigments and their occurrence during the different winemaking stages. From top to bottom the pigments shown in the figure are: malvidin-3-glucoside, malvidin-3-glucoside pyruvic acid (vitisin A), malvidin-3-glucoside-4-vinyl (vitisin B), malvidin-3-glucoside 4-vinylcatechol (pinotin A), dimer malvidin-3-glucoside-catechin, dimer malvidin-3-glucoside-ethyl-catechin, malvidin-3-glucoside-pyruvic acid vinyl catechin (portisin type A) and malvidin-3-glucoside pyruvic acid vinyl phenol (portisin type B). Yeasts species contributing to the formation of particular pigments are also indicated.