Harvest point determination of indian jujube fruit (Ziziphus mauritiana L.) based on physicochemical and functional parameters

The indian jujube (Ziziphus mauritiana) is a native fruit of South Asia and East Africa. In Brazil, it is an exotic and endemic fruit specie, brought by the colonizers in the 18th century to the state of Roraima, Brazil. In its native region presents damaging aspect, it demands severe control to prevent its invasion in the pastures and other agricultural fields. Nevertheless, it is considered a very nutritious fruit, but so far has been studied very little. Thus, the aim of this study was to find out its exact harvest time based on its physicochemical and functional properties. The study was conducted between the years of 2012 and 2016, and the fruits were collected from the individual trees in the urban area of Boa Vista city, Roraima sate, Brazil, and analyzed at 7-day interval after the anthesis (DAA). The analysis included physical analysis (diameter and fresh weight), chemical analysis (pH, total acidity, soluble solids, total sugars, reducing sugars, starch, total pectin, soluble pectin, pectin methylesterase and polygalacturonase enzymes), antioxidant activity (phenolic compounds, anthocyanins, flavones, flavonols, carotenoids, ascorbic acid, ORAC and DPPH), and pattern of respiration (CO2 and ethylene). A completely randomized design was used for the experiment with 10 phenological fruit stages and three replications, with a total of 30 sample units per each replication. For the best fit of regression model, F test was performed with a 5% probability level. At the end of the experiment, a clear fruit climacteric behavior was observed, and the antioxidant activity was connected with the presence of phenolic compounds, and based on other analyses, it was determined that the best point of harvest is 56 DAA.