Progressive Freeze-concentration of ‘Kyoho’ Grape (Vitis Labruscana Bailey) Juice and Its Application to Wine Making

Abstract

Progressive freeze-concentration (PFC) of ‘Kyoho’ grape (Vitis Labruscana Bailey) juice was carried out by a tubular ice system with circulation pump and the original juice at 19.5 Brix was concentrated up to 29.9 Brix. The PFC-concentration was proved to give a high quality concentrate with no substantial change both in organic acid distribution and flavor profile. The PFC-concentrated ‘Kyoho’ grape juice was fermented to produce a ‘Kyoho’ grape wine with 17.1 vol-% alcohol content, showing that a high alcohol content can be obtained without chaptalization in the present method. After the fermentation, some changes were observed both in the organic acid distribution and the flavor profile. As a whole, however, the ‘Kyoho’ grape wine retained enough amount of original ‘Kyoho’ grape flavors. The present results suggest a possibility to produce a new-type ‘Kyoho’ grape wine with rich ingredients and flavors.