Influence of Clarification Treatment on Concentrations of Selected Free Varietal Aroma Compounds and Glycoconjugates in Falanghina (Vitis vinifera L.) Must and Wine

¹ Dipartimento di Scienze degli Alimenti, Università degli Studi di Foggia, via Napoli 25, 71100 Foggia, Italy.

email: l.moio{at}unifg.it

Falanghina must was clarified through five methods: spontaneous settling (SS); spontaneous settling with addition of pectic enzyme (E); filtration of E (EF); fining of E with bentonite, casein, silica gel, and charcoal (EC); and EC treatment followed by filtration (ECF). The concentration of free varietal aroma compounds and glycoconjugates was then investigated. Clarification procedure did not affect the concentration of must terpenols, while a positive correlation was found between the intensity of prefermentative clarification and the content of glycoconjugates of must, as measured by glycosyl-glucose, with a trend of SS > E = EF > EC = ECF. Glycosylated precursors of linalool, geraniol, benzyl alcohol, 2-phenylethanol, and eugenol were significantly decreased by must clarification. In all treatments, fermentation resulted in a large decrease in bound geraniol, benzyl alcohol, and 2-phenylethanol. The decline of bound linalool and eugenol was smaller and varied according to yeast strain and treatment. Only free forms of linalool and benzyl alcohol were significantly increased by fermentation. Since musts with lower contents of glycosylated precursors resulted in wines with lower levels of both these compounds and of some volatiles potentially resulting from their hydrolysis, prefermentative clarification may influence both expression of varietal character and aging potential of Falanghina wine.

Note:
Acknowledgments: This research was supported by Se.S.I.R.C.A Regione Campania and Lallemand Italy. We thank Caroline Turner, MAgrSc Reading, for assistance in the preparation of the manuscript.

Key words: clarification, aroma compounds, glycosides, fermentation, Falanghina, terpenols