The Vitamin Content of Sultanina (Thompson Seedless) Grapes and Raisins

Abstract

Seedless Thompson grapes when preserved by freezing storageeven after air evacuationrapidly lose both vitamin A and B activities. These grapes are rather well endowed with vitamin B when fresh and this endowment is largely retained in the natural sun-dried and soda-dipped raisins which contain 1 International (or about 1.4 Chase and Sherman) vitamin B unit in 1.5 to 2.0 gm. Howevertreatment of the fruit with sulfur dioxide previous to drying destroys much of the vitamin. Such destruction is more striking if shown by rat growth instead of by pigeon maintenance. The fresh grapes are richer in vitamin A than has been hitherto supposed possiblebecause really fresh fruit has not previously been examined. The dehydrated raisinsboth sulfured and unsulfuredretained this factor in full1 International unit in 0.5 gm. All the sun-dried raisins had lost most of the vitamin A activity. The frozen grapes appeared to lose antiscorbutic activity in storage and even the fresh grapes were only poorly endowed with vitamin C. Very little protective value could be ascribed to any of the raisins. Vitamin G appears to be poorly represented in grapes and raisinsbut conclusive experiments are not yet available. Unsulfured soda-dipped dehydrated raisins made from Thompson seedless grapes retain practically all of the considerable vitamin A and B activity of the fresh grapes.