Carlos Escott

By Carlos Escott, Iris Loira, Antonio Morata, María Antonia Bañuelos and José Antonio Suárez-Lepe

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.

Part of the book: Yeast

By Antonio Morata, Iris Loira, Juan Manuel del Fresno, Carlos Escott, María Antonia Bañuelos, Wendu Tesfaye, Carmen González, Felipe Palomero and Jose Antonio Suárez Lepe

Trends in wine consumption are continuously changing. The latest in style is fresh wine with moderate alcohol content, high acidity, and primary aromas reminiscent of grapes, whereas certain fermentative volatiles may also influence the freshness of the wine. In addition, the effects of climate change on the composition of the grapes (high sugar content and low acidity) are adverse for the quality of the wine, also considering the microbiological stability. Herein, different strategies aiming at improving wine freshness are presented, and their performance in winemaking is discussed: among them, the addition of organic acids able to inhibit malolactic fermentation such as fumaric acid; the use of acidifying yeasts for alcoholic fermentation, such as Lachancea thermotolerans; and the selection of non-Saccharomyces yeasts with β-glucosidase activity in order to release terpene glycosides present in the must.

Part of the book: Advances in Grape and Wine Biotechnology

By Antonio Morata, Iris Loira, Buenaventura Guamis, Javier Raso, Juan Manuel del Fresno, Carlos Escott, María Antonia Bañuelos, Ignacio Álvarez, Wendu Tesfaye, Carmen González and Jose Antonio Suárez-Lepe

This chapter reviews the main non-thermal technologies with application in enology and their impact in: the extraction of phenolic compounds from grapes, the elimination of indigenous microorganisms, and the subsequent effect in SO2 reduction. The technologies are physical processes with null or low repercussion in temperature and therefore gentle with sensory quality of grapes. High hydrostatic pressure (HHP), ultra high pressure homogenization (UHPH), pulsed electric fields (PEFs), electron-beam irradiation (eBeam), ultrasound (US), and pulsed light (PL) have interesting advantages and some drawbacks that are extensively reviewed highlighting the potential applications in current technology.

Part of the book: Chemistry and Biochemistry of Winemaking, Wine Stabilization and Aging

By Antonio Morata, Carlos Escott, Iris Loira, Juan Manuel Del Fresno, Cristian Vaquero, María Antonia Bañuelos, Felipe Palomero, Carmen López and Carmen González

Lachancea thermotolerans is a yeast species that works as a powerful bio tool capable of metabolizing grape sugars into lactic acid via lactate dehydrogenase enzymes. The enological impact is an increase in total acidity and a decrease in pH levels (sometimes >0.5 pH units) with a concomitant slight reduction in alcohol (0.2–0.4% vol.), which helps balance freshness in wines from warm areas. In addition, higher levels of molecular SO2 are favored, which helps to decrease SO2 total content and achieve better antioxidant and antimicrobial performance. The simultaneous use with some apiculate yeast species of the genus Hanseniaspora helps to improve the aromatic profile through the production of acetyl esters and, in some cases, terpenes, which makes the wine aroma more complex, enhancing floral and fruity scents and making more complex and fresh wines. Furthermore, many species of Hanseniaspora increase the structure of wines, thus improving their body and palatability. Ternary fermentations with Lachancea thermotolerans and Hanseniaspora spp. sequentially followed by Saccharomyces cerevisiae are a useful bio tool for producing fresher wines from neutral varieties in warm areas.

Part of the book: Grapes and Wine

By Antonio Morata, Carlos Escott, Juan Manuel del Fresno, Buenaventura Guamis, Iris Loira, María Antonia Bañuelos, Carmen López, Felipe Palomero and Carmen González

Ultra-High Pressure Homogenization (UHPH) is an emerging non-thermal technology that uses continuous pumping at 200–600 MPa (generally 300), and then the fluid is depressurized against a special valve made with highly resistant alleys and coated with diamond powder. The UHPH process is able to sterilize grape juice or whatever food fluid and at the same time is extremely efficient in inactivating oxidative enzymes. The total elimination of wild microorganisms in grape juice allows the perfect implantation of the selected Saccharomyces cerevisiae starter facilitating the expression of particular metabolic profiles or the expression of specific extracellular activities. Furthermore, the use of complex emerging biotechnologies such as the use of co-inoculations with S. cerevisiae and lactic acid bacteria to perform simultaneously alcoholic and malolactic fermentations works much better if the initial juice has a very low load of wild microorganisms. Additionally, the development of spoilage processes by wild microorganisms that can remain in the wine after fermentation is practically impossible when the initial juice is treated by UHPH. Thus, UHPH helps to obtain wines more stable from a microbiological perspective and therefore safer and more hygienic.

Part of the book: New Advances in Saccharomyces