Apparent Vitamin C in Walnuts

Abstract

THE remarkably high vitamin C content of walnuts has been mentioned by various workers^1,2. Recent work^3,4 indicates that foods may contain substances which react with the dye and are estimated as ascorbic acid under the usual titration conditions but are not true vitamin C. This apparent vitamin C has now been found in walnuts. Twenty-one samples of five different species have been examined, and all were found to contain considerable amounts of apparent vitamin C (). The Juglans regia samples were collected in Kew, Long Ashton and Berkhamsted. All the other samples came from Kew. The flowers of many trees of Juglans and Carya were destroyed by frosts, which prevented the investigation of a wider range of species. The material available was further restricted by the depredations of grey squirrels, at present a serious pest at Kew. The nuts ranged in weight from 2 gm. to 40 gm., and included different stages of ripening up to those in which the shell had become hard and woody. Thus, apparent vitamin C should be found in walnuts which are pickled or used in jam-making, etc. Mapson⁵ has found that 14 per cent of the total vitamin C in some walnuts preserved in syrup was apparent vitamin C.