Effect of Torulaspora delbrueckii Yeast on the Anthocyanin and Flavanol Concentrations of Cabernet franc and Pinotage Wines

Abstract

Pinotage and Cabernet franc grape must were inoculated with Saccharomyces cerevisiae and Torulasporadelbrueckii yeasts. Differences in colour were observed between Pinotage (S. cerevisiae) and Pinotage (T.delbrueckii) wines, whereas differences in berry and herbaceous character were observed between Cabernetfranc (S. cerevisiae) and Cabernet franc (T. delbrueckii) wines. Mouthfeel properties between treatmentsfor both wines were not significantly different. Overall quality was slightly higher in wines inoculatedwith T. delbrueckii compared to wines inoculated with S. cerevisiae. Anthocyanins and flavanols measuredin Pinotage wines made with T. delbrueckii were higher compared to Pinotage must inoculated with S.cerevisiae. Cabernet franc wines made with S. cerevisiae were higher in anthocyanin glycoside and flavanolconcentrations compared to Cabernet franc wines made with T. delbrueckii. Insignificant differencesin acetylated and coumarylated anthocyanins were evident between Cabernet franc (S. cerevisiae) andCabernet franc (T. delbrueckii) wines. Principal component analysis showed that epigallocatechin gallate,epicatechin gallate, procyanidin B2, peonidin 3-O-glucoside, delphinidin 3-(6-acetyl) glucoside, petunidin3-(6-acetyl) glucoside, malvidin 3-(6-acetyl) glucoside and malvidin 3-O-glucoside concentrationswere highest in Pinotage wines inoculated with T. delbrueckii. Cabernet franc wines inoculated with S.cerevisiae yeasts were highest in malvidin 3-(6-p-coumaroyl) glucoside, petunidin 3-(6-p-coumaroyl)glucoside, petunidin 3-O-glucoside, epicatechin gallate and epigallocatechin gallate concentrations. Totalanthocyanins were highest in Pinotage (S. cerevisiae) wines and Cabernet franc (T. delbrueckii) wines.Flavanols were highest in Pinotage (T. delbrueckii) and Cabernet franc (S. cerevisiae) wines. It is evidentfrom the results that yeast species has an impact on the flavonoid concentrations within a grape variety.