Dried jujube (Ziziphus jujuba) was incubated at high temperature and humidity for 96 hr in blacking process and sampled every 12 hr. Results showed that the saccharose reduced from 195.6 to 3.1 g/kg rapidly in 24 hr. The total acid content was mild with 8.82 g/kg and increased to 23.45 g/kg by 177.21% with thermal processing for 96 hr. The contents of total polyphenols were enhanced during 0–48 hr processing, and the amount of the compound increased with treatment by 50.99%. The total reducing sugar increased 29.79% on 60 hr. cAMP was decreased with aging and ripening by 65.85%. 5‐HMF was keep growing to 3.52 g/kg. The volatile component had great change in black jujube fruits compared to untreated jujubes, especially treated in 12 hr. The results indicated that backing pretreatment can facilitate the generation of functional food materials and support the development of this nutrition product.

Jujube has received more and more attention due to their nutritional value and pharmacological effects. This study evaluated the quality of different varieties of jujube by comparing the main active components and antioxidant activities of thirty-seven varieties of jujube through titration, UV spectrophotometry and High performance liquid chromatography (HPLC). The results revealed that there were differences in active components and antioxidant capacity among jujube cultivars. Among the thirty-seven varieties of jujube, Qingxuyuanzao (QXYZ) had the highest contents of total phenols and flavonoids, which were 16.33 mg GAE/g DW and 41.18 mg RE/g DW, respectively, and had the highest free radical scavenging (DPPH: 29.79 mg Vc/g DW; ABTS: 50.90 mg Trolox/g DW) and reducing abilities (62.13 mg Trolox/g DW). Correlation analysis indicated that the content of total flavonoids, total phenols and phenolic acid ((+)-catechin, caffeic acid, rutin) in jujube had high positive correlation with antioxidant capacity. According to principal component analysis (PCA), the comprehensive scores of different varieties of jujube were calculated. The top five jujube varieties with comprehensive scores are ‘QXYZ,’ Suyuanling (SYL), Xiangzao (XZ), Dunhuangdazao (DHDZ) and Meimizao (MMZ). In this paper, the main active components and antioxidant capacity of thirty-seven jujube varieties have been studied, which provides a theoretical basis for jujube breeding and the development of active nutrients for jujube.

In order to investigate the purification process and antioxidant activity of triterpenic acids from blackened jujube, the macroporous resin was applied to purify the crude extract from blackened jujube. The adsorption and desorption characterizations of five different macroporous adsorption resins (AB‐8, D‐101, X‐5, HPD‐100, S‐8) for triterpenic acids of blackened jujube were compared, the optimum purification resins were screened, and the purification parameters were optimized. The antioxidant activity of crude extracts and purified products from blackened jujube was analyzed. The results showed that D‐101 resin possessed the best effect on the purification of blackened jujube triterpenic acids. The optimum purification parameters were as follows: sample concentration 25.5 μg/ml, 130 ml of the sample volume was with a flow rate of 2.0 ml/min, eluted with 95% ethanol, and speed flow was 1.0 ml/min. The purity of triterpenic acids was increased by 2.49 times after purification with a recovery rate of (78.58 ± 0.67)%. Furthermore, the IC₅₀ values of hydroxyl radical scavenging capacity from triterpenic acids crude extract and purified substances were 0.900 and 0.850 mg/ml, respectively, and the IC₅₀ values of superoxide anion radical were 0.745 and 0.594 mg/ml, respectively, indicating that the antioxidative capacity of the purified product was stronger than the crude extract. The purified triterpenic acids (PTA) groups at different doses had excellent protective effects on H₂O₂‐induced damage HUVEC cells. Results have revealed that triterpenic acids of blackened jujube have good antioxidant function and utilization and development prospects.

The isolation, purification, and antioxidant activity of polysaccharides extracted from elderberry fruits were studied. Two neutral polysaccharides (EFP-0 and EFP-1) and three acidic polysaccharides (EFP-2, EFP-3, and EFP-4) were isolated from elderberry. EFP-0, EFP-1, EFP-2, EFP-3, and EFP-4 all contain arabinose, galactose, glucose, and mannose, with molecular weights of 1.7981 × 10⁶, 7.0523 × 10⁶, 7.7638 × 10⁶, 4.3855 × 10⁵, and 7.3173 × 10⁵ Da, respectively. Structural characterization showed that the backbone of EFP-2 consisted of →4)-Manp (1→4)-β-D-Glcp (1→ and →4)-β-D-Glcp (1→5)-α-L-Araf (1→units, and T-α-L-Araf (1→ and T-β-D-Galp (1→ residues were detected by methylation analysis and NMR analysis. In addition, the MTT assay and zebrafish oxidative damage assay showed that EFP-2 had a protective effect on H₂O₂-damaged RAW264.7 cells in a dose-dependent manner, and zebrafish with the addition of EFP-2 would have low levels of ROS in vivo which showed significant antioxidant activity. Therefore, the results showed that the elderberry polysaccharides have antioxidant activity and can be used as potential antioxidants in functional foods.