Influence of Yeasts in Wine Colour

Colour is the first impression that the consumer receives from wine and it influences the taste. Colour gives an idea about wine quality, age, oxidation and structure, so it has an important repercussion on the consumer perception of wine. Yeasts promote the formation of stable pigments by the production and release of fermentative metabolites affecting the formation of vitisin A and B type pyranoanthocyanins. The hydrox- and ycinnamate decarboxylase activity showed by some yeast strains produces highly reactive vinylphenols stimulating the formation of vinylphenolic pyranoanthocyanins from grape anthocyanin precursors during fermentation. Some yeasts also influence the formation of polymeric pigments by unclear mechanisms that can include the production of linking molecules such as acetaldehyde. Grape anthocyanins adsorbed in yeast cell walls during fermentation are removed from wine after racking processes affecting final pigment content. Moreover, the intensive use of non‐Saccharomyces yeasts in current oenology makes it interesting to assess the effect of new species in the improvement of wine colour

Wine Spoilage Yeasts: Control Strategy

Traditionally in winemaking, sulphur dioxide (SO2) is chemically the most widely used for microflora control as antimicrobial preservative. Other tested compounds for selective yeast control are sorbic and benzoic acids. Herein, we discuss the effectiveness and the application of traditional and novel treatments and biotechnologies for chemical and biological control of wine spoilage yeasts. The versatility of the killer toxins and the antimicrobial properties of natural compounds such as carvacrol, essential oils and bioactive peptides will be considered. Some of the wine spoilage yeasts that are intended to control belong to the genera Zygosaccharomyces, Saccharomycodes and Dekkera/Brettanomyces, but also the non-Saccharomyces yeasts species dominating the first phase of fermentation (Hanseniaspora uvarum, Hansenula anomala, Metschnikowia pulcherrima, Wickerhamomyces anomalus) and some others, such as Schizosaccharomyces pombe, depending on the kind of wine to be produced

Selected yeast strains (Saccharomyces cerevisiae) with glycolytic inefficiency and metabolic inhibitors to reduce alcoholic degree in vines from warm regions

n warm regions potential alcoholic degree and unequilibrated must, especially in acidity are real problems to be resolved. Strains of Saccharomyces cerevisiae have different yields to produce ethanol from the same content of sugars. These peculiarities can be named glycolytic inefficiencies. We can select yeast strains with these properties in order to reduce the final alcoholic degree together with the production of some metabolic intermediates that can have repercussion in the sensorial profile like polyalcohols or organic acid

Empleo de fermentaciones secuenciales con levaduras no-Saccharomyces y aplicación de bloqueadores metabólicos para reducir el grado alcohólico en vinos

La combinación secuencial de especies no-Saccharomyces y Saccharomyces durante la fermentación y la adición de bloqueadores metabólicos como el furfural, o-vainillina, glicolaldehído y p-benzoquinona pueden resultar unas técnicas de vinificación interesantes para reducir el grado alcohólico del vino. El grado alcohólico se determinó por HPLC-IR y los azúcares residuales mediante tests enzimáticos. Las cepas de levadura 7013 (Torulaspora delbrueckii) y 938 (Schizosaccharomyces pombe) destacaron por su capacidad para reducir significativamente el grado alcohólico (reducción media del 2.1 % v/v) dando lugar a un vino seco (azúcares menor que 1.5 gl-1) en fermentación secuencial con la 7VA (Saccharomyces cerevisiae). La o-vainillina permitió una disminución en el contenido de etanol del 0.54 % v/v a dosis de 50 mg l-1, mientras que el efecto bloqueador del glicolaldehído fue más efectivo a la dosis de 200 mg l-1 con una reducción del 0.95 % v/v. Finalmente con la p-benzoquinona se logró una reducción en el grado alcohólico de hasta 0.85 % v/v

Selección Saccharomyces cerevisiae con baja producción de etanol para control del grado alcohólico en zonas cálidas

En la enología española existen muchas regiones en las que el clima favorece maduraciones sacarimétricas excesivas lo que supone que durante la fermentación se alcancen grados alcohólicos elevados. La levadura metaboliza el azúcar (glucosa y fructosa) por vía fermentativa produciendo como productos mayoritarios etanol y CO2. Sin embargo, no todas las levaduras alcanzan el mismo grado alcohólico para un mosto con una concentración de azúcares igual. Normalmente las variaciones son pequeñas y se relacionan con desviaciones del metabolismo glicolítico hacia otras moléculas que pueden ser interesantes desde el punto de vista sensorial (Figura 1). Este tipo de levaduras permiten controlar el grado alcohólico excesivo a la vez que pueden favorecer la formación de metabolitos que incrementen la complejidad sensorial de los vinos. En este trabajo se han estudiado 25 levaduras seleccionadas para la elaboración de vinos tintos en distintas DOs españolas para evaluar su eficiencia glicolítica y por tanto el grado alcohólico alcanzado por cantidad de azúcar metabolizada para seleccionar levaduras que permitan reducir el grado alcohólico

Influence of sequential and mixed fermentations with non-Saccharomyces yeasts on the sensory profile of red wine

The aim of this work is to evaluate the influence of S. pombe and T. delbrueckii species on the sensory quality of red wine when used in sequential and mixed fermentations with S. cerevisiae

Acceleration of ageing on lees in red wines by application of ultrasounds

A transfer of parietal polysaccharides and mannoproteins is produced during aging on lees [1]. This transfer of compounds to wine is carried out after cell death. It comes to breakdown of polysaccharides from cell wall (yeast autolysis). This technique increases the density in wines [2] and gives more body and structure. Interactions between yeast polysaccharides and wine tannins will result in decrease of tannic perception (decrease of astringency). Increase of varietal characteristics is produced. The main disadvantage of the ageing on lees is the time that the process requires. Usually, nine months are necessary at least for obtaining a noticeable effect in wines. The objective of this work is the acceleration of this process using ultrasounds to lyse the yeast cell wall. In addition, the influence of this technique in different red wine quality parameters was studied

Use of Schizosaccharomyces pombe and Torulaspora delbrueckii strains in mixed and sequential fermentations to improve red wine sensory quality

One of the main opportunities in the use of non- Saccharomyces yeasts is its great intraspecific variability in relation to the synthesis of secondary products of fermentation. Thus, mixed or sequential fermentation with non- Saccharomyces can increase the synthesis of certain metabolites that are important for colour stability, such as acetaldehyde and pyruvic acid (vitisin precursors) or vinylphenols (vinylphenolic pyranoanthocyanin precursors). Furthermore, the selection and use of non- Saccharomyces yeast strains with good yields in the production of certain volatile compounds (ethyl lactate, 2,3-butanediol, 2-phenylethyl acetate), with limited formation of higher alcohols, is a way to improve the aromatic profile of red wine. The main aim of this work was to evaluate the influence of sequential and mixed fermentations with Schizosaccharomyces pombe and Torulaspora delbrueckii strains on red wine's sensory quality. Anthocyanins and aromatic profiles, as well as glycerol and organic acid content, were analysed in the red wines obtained. Results show that, in general, mixed fermentations can promote an increment in polyols synthesis, while sequential fermentations can enhance the herbaceous aroma. Moreover, the use of T. delbrueckii in mixed fermentations allowed an increase to the fruity character of red wine. The use of S. pombe in sequential fermentations increased the stability of the colouring matter by favouring vitisins and vinylphenolic pyranoanthocyanin formation. \ua9 2015 Elsevier Ltd

Polymeric pigments formed in sequential fermentation of red fresh musts by adding flavan-3-ols

Red wine pigments are susceptible to degradation by light, SO2 and changes in pH and temperature1,2. The formation of pyranoanthocyanins and polymeric pigments during fermentation and wine aging promote the stability of such pigments3. Glycolytic metabolites (e.g. acetaldehyde and pyruvic acid) may interact with anthocyanins and flavan-3-ols to form more stable molecules4 without a drastic change in hue values. Procyanidins are molecules from the flavanoids family that may condense with anthocyanins5. The contribution of non-Saccharomyces yeasts (e.g. L. thermotolerans, M. pulcherrima and T. delbrueckii), in sequential fermentation with S. cerevisiae and S. pombe, to the production of stable pigments was assessed in this project. with the use of HPLC-DAD/MS-ESI. The red musts have been enriched with flavanols prior fermentation. Fermentative volatiles and sensorial analysis were also performed to characterize experimental wines produced

Use of Schizosaccharomyces pombe to produce stable pigments during red winemaking

This work has studied the production of stable pyranoanthocyanin pigments during fermentation using S. pombe and Saccharomyces cerevisiae. Along the fermentation, anthocyanins were determined by HPLC-DAD/MS, acetaldehyde was measured using GC-FID and pyruvic acid was quantified by enzymatic tests. Results show that S. pombe strains produce higher amounts of pyruvic acid, and therefore also of vitisin A, than Saccharomyces controls