Changes of some horticultural characteristics in jujube (Ziziphus jujube mill.) fruit at different ripening stages

Abstract

In this study, changes in some horticultural characteristics of jujube fruits at two ripening stages were investigated. The ripening stages were determined by reference degree (%) of the red zone on the surface of the fruit: white ripening stage (WR), 5–15%; red ripening stage (RR), 95–100%. Fruit weight, length, width, color, and firmness were examined as morphological characteristics; phenolics, organic acids, fatty acids, and sugars were evaluated as biochemical characteristics. Fruit weight was 22.63 g in the WR stage and 28.42 g in the RR stage. The dominant phenolic acid was p-hydroxybenzoic acid in both ripening stages (623 mg 100 g–1 in WR, 370 mg 100 g–1 in RR). Catechin, epicatechin, and gallic acids increased at the RR stage compared to WR, while protocatechuic and p-hydroxybenzoic acids decreased. The examined organic acids had higher values at the RR stage and all results were found to be statistically significant. Malic acid was the dominant organic acid in both ripening stages. The dominant sugar was fructose in both ripening stages, followed by glucose and sucrose. The fatty acid analysis showed that jujube fruits are rich in unsaturated fatty acids. The predominant fatty acid was oleic acid, followed by palmitic and linoleic acids. The present study revealed that the RR stage of jujube fruits was found appropriate for the human diet compared to the WR stage.