Preservative Effect of Vitamin K₅ and Sulfur Dioxide on Sweet Table Wine

Abstract

In recent years, several preservatives other than sulfur dioxide have been tested for wine. Each preservative has its advantages and disadvantages. Vitamin K₅ has been tested by various investigators. This vitamin (4-amino-2-mefhyl-1-naphthol hydrochloride), an analog of vitamin K,has demonstrated a marked inhibitory activity toward a number of microorganisms. Previous work on vitamin K₅ in wine was with the vitamin alone. This paper presents the combined effect of vitamin K₅ and sulfur dioxide on sweet table wines. Vitaman K₅ used with sulfur dioxide showed distinct advantages over the vitamin used alone. Aside from its own preserving effects, sulfur dioxide stabilized vitamin K₅, thus increasing its effectiveness.

Vitamin K₅ was effective against yeast cells with low initial counts but was ineffective at high initial counts, even with the help of sulfur dioxide. In wines where 12 per cent of alcohol was present, a combination of 10 ppm of vitamin K₅ and 100 ppm of sulfur dioxide offered sufficient protection against secondary fermentation.

Alcohol concentrations exhibited some effects on the requirements of vitamin K₅ and sulfur dioxide in preventing secondary fermentations. In the presence of 14 per cent of alcohol, both vitamin K₅ and sulfur dioxide requirements were reduced significantly.

Sensory evaluations revealed that the taste of the vitamin developed with storage and that 50 ppm of vitamin K₅ is probably the taste threshold of this preservative when 100 ppm of sulfur dioxide is present. Vitamin K₅ darkened white wines slightly in the absence of sulfur dioxide, but 100 ppm of sulfur dioxide prevented the darkening even with the addition of 50 ppm of vitamin K₅.