Progressive freeze-concentration of uruby romany grape (vitis labruscana bailey) juice and its application to wine production

Abstract

uRuby Romany grape (Vitis Labruscana Bailey) juice was concentratedfrom 14.6 to 23.0 Brix by progressive freeze-concentration (PFC) with a closed circulation flow system. The distribution of organic acids and flavors was measured, andno substantial changes were observedin the component profiles before andafter PFC concentration. The PFC-concentrateduRuby Romany grape juice was fermentedto produce Ruby Roman wine, in which the obtainedethanol concentration was as high as 14.5 vol%. Thus, a sufficient alcohol level can be obtainedwithout chaptalisation by using PFC concentration. Following fermentation, acetic andsuccinic acids increasedin the organic acid distribution. In the flavor distribution, some components in the original juice disappeared, while fermentation products such as ethanol, isoamyl acetate, isoamyl alcohol, ethyl octanoate, phenethyl alcohol, octanoic acid, and decanoic acid newly appeared. Overall, the Ruby Roman wine retained sufficient amounts of flavors from the original juice. The present results suggest the possibility of producing a new-type of Ruby Roman wine, not presently available on the market.