RESUMO
Jujube(Zizyphus vulgaris Lam)is a popular fruit in North China. The fruit is mainly marketed after dehydration. However, there are no less than twenty rarities sold in Peking while fresh during the months of August and October.The ascorbic acid content of 16 varieties of the fresh fruit has been determined. The values found are all above 300 mg per 100 g of edible portion—mostly between 400-600 mg, the highest being above 1,000 mg. It is certainly worth noting that, as a class of ordinary food, Jujube has the highest ascorbic acid content.As the fruit ripens, i. e. the colour turns from green to red and the texture changes from hard to soft, its ascorbic acid content decreases. When the sample was stored at 0-4℃ for about one and a half months, the fruits which remained hard lost about 10％ of its ascorbic acid; when the fruit had become somewhat soft, the amount of ascorbic acid decreased drastically and the dehydro-form increased correspondingly while the total amount remained practically unchanged.Experiment with human subjects indicated that the utilization of the ascorbie acid of Jujube is 86.3-93.0％ of the pure vitamin.
