Organic acid and aromatic compounds create distinctive flavor in the blackening process of jujube.

Previous studies demonstrated jujube blackening effectively increased cyclic adenosine phosphate and triterpene acid levels, improving its nutritional value. However, compositional changes during this process require further elucidation. The objective aimed to analyze compositional transformations during this process with SEM, TPA, UPLC-MS, E-nose. Results showed decreased hardness, springiness, and chewiness coupled with increased gumminess over blackening durations. Untargeted omics analysis revealed increases of 2-aminooctadec-8-ene-1,3,4-trioland carbendazim. Targeted organic acid analysis showed initial citric acid accumulation (1481.62 to 1645.78 mg/kg) in the first 24 h, then declines to 1072.96 mg/kg. Meanwhile, oxalic and lactic acids steadily rose, peaking at 96-120 h before slightly decreasing. E-nose analysis implied alterations in organic sulfide aromatics engendered the characteristic flavors. Organic acid fluctuations likely resulted from sugar biotransformation and thermal degradation. These comprehensive analyses demonstrate jujube blackening imparts a rich and unique flavor, providing theoretical support for investigating the mechanisms and products underlying this process.

The dispersibility of biphasic stabilized oil-in-water emulsions improved by the interaction between curdlan and soy protein isolate.

Curdlan, a natural polysaccharide, exhibits emulsion-stabilizing and viscosity-modifying properties. However, when employed solely in the aqueous phase, curdlan's adhesive nature impedes droplet dispersion, resulting in a gel-like structure with limited applicability. This investigation formulated a biphasic stabilized oil-in-water emulsion by supplementing the oil phase with beeswax and the aqueous phase with curdlan and soy protein isolate (SPI). The addition of SPI transformed the structural characteristics from a gel-like to a mayonnaise-like structure. Maximal electrostatic repulsion was observed at an internal phase volume fraction of 30%, effectively precluding droplet aggregation owing to the absolute zeta potentials surpassing 40 mV. The emulsions displayed shear-thinning rheological behavior, with a higher storage modulus than the loss modulus, indicative of favorable elastic properties. Molecular docking revealed the predominant role of polar amino acids in facilitating hydrogen bond formation. This study provides a template for developing emulsions with biphasic stability and desirable dispersibility.

An Acidic Polysaccharide with Anti-Inflammatory Effects from Blackened Jujube: Conformation and Rheological Properties.

An acidic polysaccharide fraction (BJP-4) was isolated from blackened jujube, and its advanced structures and anti-inflammatory activity were investigated. X-ray diffraction showed that BJP-4 exhibits both crystalline and amorphous portions. Atomic force microscopy data suggested that it contains a large number of spherical lumps. Circular dichroism and Congo red experiments revealed that it has no triple-helix conformation. In steady shear flow results, the BJP-4 solution was a pseudoplastic non-Newtonian fluid with acid-base stability. BJP-4 (20 mg/mL) showed liquid-like properties (G″ > G'), while it performed weak gel-like behavior at a high concentration (40 mg/mL) (G' > G″). The anti-inflammatory effects of BJP-4 were further evaluated through in vitro experiments. BJP-4 could down-regulate the over-secretion of inflammatory factors (NO, IL-6, IL-1ß, TNF-α, iNOS and COX-2) in RAW264.7 cells due to LPS stimulation. Moreover, it demonstrated that BJP-4 restrained the NF-κB signal pathway by regulating TLR4 expression, reducing IκBα phosphorylation level and NF-κB p65 nuclear translocation. In summary, this present study contributes to the application of blackened jujube polysaccharides in the foods and medicine field.

A novel acidic polysaccharide from blackened jujube: Structural features and antitumor activity in vitro.

Liver cancer is one of the most common cancers, with increasing trends in incidence and mortality. A novel acidic polysaccharide (BJP-2) obtained from blackened jujube was extracted by hot water followed by chromatographic purification employing DEAE-cellulose 52 and Sephadex G-100 column. And then BJP-2 was identified by SEC-MALLS-RI, GC-MS, methylation and NMR for the following characteristics: molecular weight of 6.42 × 104 Da, monosaccharide composition of glucuronic acid (GalA), arabinose (Ara), galactose (Gal), rhamnose (Rha), xylose (Xyl), glucuronic acid (GlcA), glucose (Glc), fucose (Fuc) and mannose (Man) with the percentage of 39.78, 31.93, 16.86, 6.43, 1.86, 1.28, 1.02, 0.61, and 0.23%, as well as the main chain of → 5)-α-L-Araf (1 → 4)-ß-D-Gal(1 → , T-α-L-Araf (1 → 4)-ß-D-Gal(1 → , and → 4)-α-L-6MeGalAp(1 → . The effect of BJP-2 on the apoptosis of HepG2 cells and its anti-tumor mechanism were further explored. The analysis by MTT and flow cytometry showed that BJP-2 suppressed cell proliferation by inducing apoptosis in a concentration-dependent manner. Cell scratching and Transwell revealed that BJP-2 was able to block the invasion and metastasis of tumor cells. Western blot results demonstrated that BJP-2 exhibited antitumor activity through a mitochondria-dependent pathway, as evidenced by overexpression of Bax, Cleaved Caspase-3/Caspase-3 and Cleaved Caspase-9/Caspase-9 and downregulation of Bcl-2. Therefore, BJP-2 has broad research prospects as a tumor preventive or therapeutic agent.

Extraction, isolation, structural characterization, and antioxidant activity of polysaccharides from elderberry fruit.

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)-ß-D-Glcp (1→ and →4)-ß-D-Glcp (1→5)-α-L-Araf (1→units, and T-α-L-Araf (1→ and T-ß-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.

Preparation, structural characterization and antioxidant activity of water-soluble polysaccharides and purified fractions from blackened jujube by an activity-oriented approach.

This study aimed to investigate the structural features and antioxidant activity in vitro of crude blackened jujube polysaccharides (BJPs) and five purified polysaccharides based on the activity-oriented approach. The crude BJPs exhibited dose-dependent radical scavenging activity and total reducing capacity, and provided excellent protective effects against H2O2-damaged HUVECs via up-regulating mitochondrial membrane potential and down-regulating intracellular reactive oxygen species. After fractionation by column chromatography, the five purified components differed in chemical composition, molecular weight, monosaccharide composition (type and relative proportion) and FTIR band (peak pattern or intensity, especially in the range of 1000.0-1200.0 cm-1), as well as protective effects against H2O2-induced HUVECs. As the most abundant and potent antioxidant component, the backbone of BJP-3 was mainly composed of →4)-α-l-GalpA (1→, →5)-α-l-Araf (1→ residues with two terminals of T-α-l-Araf (1→ and T-ß-d-Galp (1→. The above results compared the structural and bioactive properties of different blackened jujube polysaccharides and highlighted their potential as antioxidants for functional foods.

Purification and antioxidant properties of triterpenic acids from blackened jujube (Ziziphus jujuba Mill.) by macroporous resins.

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.

Structural characterization and antioxidant activities of one neutral polysaccharide and three acid polysaccharides from Ziziphus jujuba cv. Hamidazao: A comparison.

A neutral polysaccharide (HJP-1a) and three acid polysaccharides (HJP-2, HJP-3 and HJP-4) were obtained from Z. jujuba cv. Hamidazao. HJP-1a was mainly composed of arabinose and galactose in a ratio of 56.9:20.0, with an average molecular weight of 3.115 × 104 g/mol. HJP-2, HJP-3 and HJP-4 were homogeneous heteropolysaccharides mainly containing galacturonic acid, arabinose and galactose, with average molecular weights of 4.590 × 104, 6.986 × 104 and 1.951 × 105 g/mol, respectively. Structural characterization indicated that the backbone of HJP-3 appeared to be mainly composed of →4)-α-d-GalpA (1→ and →2,4)-α-l-Rhap (1→ residues with some branches consisting of →5)-α-l-Araf (1→ residues and terminals of T-α-l-Araf (1→ and T-ß-d-Galp residues. The four purified fractions displayed dose-dependent radical scavenging activity on ABTS+ radicals and reducing capacity, as well as excellent protective effect on H2O2-induced HepG2 cells and metronidazole-damaged zebrafish embryos, especially HJP-2 in vitro and HJP-1a in vivo. Therefore, the polysaccharides from Z. jujuba cv. Hamidazao could be used as a potential antioxidant in functional foods.

The regulation of cell wall lignification and lignin biosynthesis during pigmentation of winter jujube.

Fruit lignification is due to lignin deposition in the cell wall during cell development. However, there are few studies on the regulation of cell wall lignification and lignin biosynthesis during fruit pigmentation. In this study, we investigated the regulation of cell wall lignification and lignin biosynthesis during pigmentation of winter jujube. The cellulose content decreased, while the lignin content increased in the winter jujube pericarp during pigmentation. Safranin O-fast green staining showed that the cellulose content was higher in the cell wall of winter jujube prior to pigmentation, whereas the lignin in the cell wall increased after pigmentation. The thickness of the epidermal cells decreased with pericarp pigmentation. A combined metabolomics and transcriptomics analysis showed that guaiacyl-syringyl (G-S) lignin was the main lignin type in the pericarp of winter jujube, and F5H (LOC107424406) and CCR (LOC107420974) were preliminarily identified as the key genes modulating lignin biosynthesis in winter jujube. Seventeen MYB and six NAC transcription factors (TFs) with potential regulation of lignin biosynthesis were screened out based on phylogenetic analysis. Three MYB and two NAC TFs were selected as candidate genes and further studied in detail. Arabidopsis ectopic expression and winter jujube pericarp injection of the candidate genes indicated that the MYB activator (LOC107425254) and the MYB repressor (LOC107415078) control lignin biosynthesis by regulating CCR and F5H, while the NAC (LOC107435239) TF promotes F5H expression and positively regulates lignin biosynthesis. These findings revealed the lignin biosynthetic pathway and associated genes during pigmentation of winter jujube pericarp and provide a basis for further research on lignin regulation.

Content variations in compositions and volatile component in jujube fruits during the blacking process.

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.