molecules Article Effect of Lachancea thermotolerans on the Formation of Polymeric Pigments during Sequential Fermentation with Schizosaccharosmyces pombe and Saccharomyces cerevisiae Carlos Escott 1,* , Antonio Morata 1 , Jorge M. Ricardo-da-Silva 2 , María Jesús Callejo 1, María del Carmen González 1 and José Antonio Suarez-Lepe 1 1 enotecUPM. Chemistry and Food Technology Department, School of Agronomic, Food and Biosystems Engineering. Universidad Politécnica de Madrid, Av. Puerta de Hierro 2, 28040 Madrid, Spain;
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[email protected] (J.A.S.-L.) 2 LEAF-Linking Landscape, Environment, Agriculture and Food, Instituto Superior de Agronomia, Universidade de Lisboa, Tapada da Ajuda, 1349-017 Lisboa, Portugal;
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[email protected]; Tel.: +34-91-336-57-30; Fax: +34-91-336-57-46 Received: 30 July 2018; Accepted: 12 September 2018; Published: 14 September 2018 Abstract: Anthocyanins in red grape musts may evolve during the winemaking process and wine aging for several different reasons; colour stability and evolution is a complex process that may depend on grape variety, winemaking technology, fermentative yeast selection, co-pigmentation phenomena and polymerization. The condensation of flavanols with anthocyanins may occur either with the flavylium ion or with the hemiacetal formation in order to produce oligomers and polymers. The kinetics of the reaction are enhanced by the presence of metabolic acetaldehyde, promoting the formation of pyranoanthocyanin-type dimers or flavanol-ethyl-anthocyanin structures. The experimental design carried out using white must corrected with the addition of malvidin-3-O-glucoside and flavanols, suggests that non-Saccharomyces yeasts are able to provide increased levels of colour intensity and larger polymeric pigment ratios and polymerization indexes.