Physicochemical and Antioxidant Capacity of Jujube (Ziziphus jujuba Mill.) at Different Maturation Stages

Jujube is a crop very resistant to drought and salinity, making it an interesting growing alternative in southeastern Spain. The characteristics of five different cultivars of the jujube fruit have been evaluated and classified into four different maturation stages according to the color of the peel, ranging from green in its most immature stage, to white, yellow, and red in its last, more mature stage. This is due in part to the amount of carotenoids and chlorophylls studied, which vary as the fruit matures. The cultivars ‘GAL-E’ and ‘GAL-T’ are the largest in size and weight, followed by ‘MSI’, ‘PSI’, and ‘DAT’, which are the smallest cultivars. The content of phenolic compounds was also analyzed. The antioxidant activity, which was studied by different methods, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP), showed the highest activity in stages 3 and 4 of jujube fruit. The antioxidant activity studied in the hydrophilic and lipophilic fraction by the ABTS method showed the highest peak in stages 1 and 2. This is an important information to know promising cultivars to be used in future breeding programs. Moreover, the maturation stage is relevant to obtain fruit with a high content of bioactive compounds as well as interesting organoleptic properties.