The glucose - fructose ratio of California grapes

Because of the high sweetness of fructose table grape varieties of high fructose content would be of interest for cold climates. For producing stable sweet table wines with ordinary yeasts high fructose varieties would be desirable. With the Sauternes strain of yeast high glucose varieties would be favored.The LOTHROP-HOLMES method gave good recovery of added glucose, duplicable results, and minor interference of fructose.The glucose/fructose ratio of California grapes at maturity varies over a wide range, from at least 0.80 to 1.12. There is, however, considerable variability in the ratio between different vines.Further data should be obtained for a large number of varieties in order to discover as wide a range of ratios as possible. Plant breeders could then use this information in their experiments

Efeito da adição de sulfato de amônio sobre a produção de ácido succínico durante a fermentação alcoólica

Succinic acid production by yeasts during alcoholic fermentation of cane molasse supplemented with 25, 50 and 100 ppm of nitrogen in the form of ammonium sulfate was determined by gas-liquid chromatography. Ethanol production was not effected by the different levels of nitrogen, but there was a significant reduction in the content of succinic acid which was inversely related with the ammonium sulfate concentration in the medium.A produção de ácido succínico por leveduras durante a fermentação alcoólica de mosto de melaço suplementado com 25, 50 e 100 ppm de nitrogênio na forma de sulfato de amônio foi determinada por cromatografia em fase gasosa. A adição de nitrogênio amoniacal não afetou significativamente a produção de álcool etílico. Houve redução significativa no teor de ácido succínico com o aumento da quantidade de nitrogênio adicionada