Dr Daniela Barbera, for help with the triangle tests. We thank Dr Antonio Sparacio and the oenologist Salvatore Sparla for help with the Merlot and Nero d'Avola grapes. We also acknowledge the "Valle dell'Acate" winery for help with the Frappato grapes. Funds for this work were provided through an intramural grant of the IRVO
Background and Aims: Somatic mutations are the major source of intra-varietal variability in some species such as grapevine (Vitis vinifera L.) that are propagated vegetatively. Aglianico and Muscat of Alexandria are two cultivars mostly cultivated in the south of Italy, showing great intra-varietal diversity. The variability of 15 clones of Aglianico belonging to three biotypes, Taburno, Taurasi and Vulture, and 21 clones of Muscat of Alexandria, coming from France, Greece, Italy and Spain, was investigated. Methods and Results: The intra-varietal diversity was investigated by ampelographic and eno-carpological (berry characteristics of oenological interest) methods (nine OIV descriptors, related to bunch and berry morphology, sugar content, total acid content and pH of must), chemical (anthocyanins, aromatic compounds and phenolic substances) and genetic analysis [18 K SNPs, single nucleotide polymorphisms (SNP)]. Intra-varietal diversity has been detected in both cultivars, mainly based on differences in the accumulation of secondary metabolites. The Taurasi biotype was discriminated by linear discrimination analysis mainly for the proportion of malvidin-3-O-glucoside acetate and methoxylated anthocyanins, while the Spanish Muscat biotype was discriminated based on the proportion of flavanols and hydroxycinnamic acids. Conclusions: Ampelography and the concentration of secondary metabolites have proved to be the best tools for the characterisation of the intra-varietal variability of grapevine germplasm. The high-throughput genetic analysis based on 18 K SNP loci did not highlight a polymorphism sufficient to distinguish among biotypes of the same cultivar, suggesting that a different molecular approach has to be adopted. Significance of the Study: This study confirms that intra-varietal diversity is better examined with a multidisciplinary approach.
Background and Aims: Some wineries, in order to promote the growth of yeasts able to ferment grape musts, traditionally produce wines using the 'pied de cuve' method. The aim of the present work was to study the performance of fortified pied de cuve (FPdC) prepared by addition of wine. Method and Results: Two FPdCs were prepared with the addition of wine at 1.5 and 3% (v/v) of ethanol to the musts and allowed to spontaneously ferment. The FPdCs were then added to fresh bulk musts in order to accelerate the spontaneous alcoholic fermentation (AF). Interestingly, several Saccharomyces cerevisiae strains isolated during the pied de cuve preparation were detected at the highest concentration throughout AF. The chemical composition of the wines conformed to commercial regulations. The volatile organic compounds (VOCs) were mainly represented by diethyl succinate and ethyl lactate, as well as by hexanol and isoamyl alcohol. Principal component analysis of the chemical parameters, VOCs and sensory data showed that the use of experimental pied de cuve influenced positively the composition of the final wines. Conclusion: The FPdC had no negative impact on the microbiological and chemical composition of wines, but it affected the diversity of the species S. cerevisiae present during AF and the sensory profile of the final wine. Significance of the Study: This study provided evidence that FPdC accelerates spontaneous AF and influences the sensory profile of red wines.
In 2011 vintage, the evolution of monomer and total anthocyanins, as well as of total flavonoids and polyphenols of grapes and wine of Nero d'Avola and Perricone, varieties cultivated in Sicily, was studied. Anthocyanin profiles are commonly used for grapevine cultivar identification because it is currently accepted that this trait is closely related to their genetic characteristics. The concentration of Nero d'Avola and Perricone anthocyanins was determined by HPLC-DAD.
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