Jujube, a Vitamin C Rich Fruit

Jujube (Ziziphus jujuba Mill.) belongs to the Rhamnaceae family. It was domesticated from its wild relative-wild jujube (Ziziphus spinosa) in China and gradually become the current species Z. jujuba. Jujube cultivars have been imported into the U.S. since 1908. The vitamin C content of jujube fruit is 4-10 times higher than orange. Jujube fruit is also known as natural vitamin C pills in China. The NMSU Alcalde Center started its jujube research and extension program in 2010. Now there are over 50 jujube cultivars at NMSU Alcalde. We have been evaluating jujube vitamin C content with 2-6-dichlorophenol indophenol titration method since 2011. Among the 50 cultivars tested, their fruit vitamin C content ranged from 200 to 600 mg/100g fresh weight, higher than most fruit and veggies species, with ‘Youzao’ having the highest content at 858mg/100g fresh weight. Jujube vitamin C content varied slightly from year to year but each cultivar kept its vitamin C content relatively constant. ‘Shuimen’ always had the lowest and ‘Youzao’ had the highest vitamin C content among the cultivars tested. Most fresh eating cultivars like ‘Li’, ‘Li-2’, ‘Redland’, ‘Daguazao’, and ‘Dabailing’ were relatively low in vitamin C content while the drying cultivars were on the high end for vitamin C content. During the fruit ripening process, fruit vitamin C content dropped from white mature stage to full red stage. After steaming/boiling for 20 minutes, jujube fruit still retained 80-90% of its original vitamin C content. Even after baking for an hour at 375 °F, jujube fruit still kept 50% of its original vitamin C content. After cold storage at 32-35 °C for 2 month, Sherwood still kept 90% of its vitamin C content. Jujube would be a good vitamin C sources for human consumption and 3-5 fresh jujube fruit would meet our daily vitamin C requirement.