Changes in Nonvaolatile Acids of Concord Grapes During Maturation

Separation by GLC indicated the major nonvolatile acids in Concord grapes to be tartaric and malic with lesser quantities of succinic, citric, quinic and ascorbic acids present. In the less mature fruit, malic acid was present in greater quantities than tartaric acid; however, as the grape berries ripened malic acid was apparently metabolized more rapidly than was tartaric acid so that tartaric became the dominant acid present in the fully ripe fruit.