Novel self-assembled aggregates of stearic acid (SA)-modified burdock polysaccharide (BP) for loading lutein were constructed, and the release and absorption properties of lutein in the aggregates in simulated gastrointestinal fluid were investigated. Three different degrees of substitution (DS) of SA-BPs were used to embed lutein, resulting in the encapsulation efficiency exceeding 90%. The aggregates were uniformly spherical, with a particle size range of 227–341 nm. XRD analysis revealed that lutein was present in a non-crystalline state within the aggregates. FT-IR and FS analysis demonstrated that lutein was located in the hydrophobic domains of SA-BP. The highest bioavailability of lutein in these aggregates reached 4.36 times that in the unmodified samples. These aggregates were able to remain stable in gastric juice and enhance the release rate of lutein in intestinal fluid. The transport of lutein-loaded SA-BP aggregates in Caco-2 cells competed with P-glycoprotein inhibitors, mainly promoting the transmembrane absorption of lutein through caveolae (or lipid raft)-related and clathrin-dependent endocytosis pathways. The above results suggest that SA-BP aggregates have the potential to be promising carriers for the efficient delivery of hydrophobic lutein.

Hemicellulose is a highly abundant, ubiquitous, and renewable natural polysaccharide, widely present in agricultural and forestry residues. The enzymatic hydrolysis of hemicellulose has generally been accomplished using β-xylosidases, but concomitantly increasing the stability and activity of these enzymes remains challenging. Here, we rationally engineered a β-xylosidase from Bacillus clausii to enhance its stability by computation-aided design combining ancestral sequence reconstruction and structural analysis. The resulting combinatorial mutant rXYLOM25I/S51L/S79E exhibited highly improved robustness, with a 6.9-fold increase of the half-life at 60 °C, while also exhibiting improved pH stability, catalytic efficiency, and hydrolytic activity. Structural analysis demonstrated that additional interactions among the propeller blades in the catalytic module resulted in a much more compact protein structure and induced the rearrangement of the opposing catalytic pocket to mediate the observed improvement of activity. Our work provides a robust biocatalyst for the hydrolysis of agricultural waste to produce various high-value-added chemicals and biofuels.

AbstractIn order to obtain amphiphilic polysaccharide self-assembly micelles, the hydrophobic modification by grafting stearic acid (SA) onto the backbone of burdock root polysaccharide (BRP) was carried out and its main physicochemical properties were characterized. The results showed that the optimal esterification conditions were as follows: reaction time of 2 h, reaction temperature of 55 ℃, system pH of 8.0 and the SA addition of 4 mmol, a maximum substitution degree (DS) of the esterification products was obtained as 0.1012. The FTIR analysis verified that the modified polysaccharide successfully introduced the ester carbonyl group. 1H NMR spectra further confirmed that the esterification reaction occurred. The SA-modified BRP micelles were roughly spherical with uniform dispersion and the particle size was in the range of 259–352 nm, which showed a negative correlation with the DS. The solubility of the esterification products also decreased. The smaller critical micelle concentration (CMC) led to easier formation of self-aggregating micelles and stronger solubilization effect. The above results indicated that SA-modified BRP as a novel carrier material possessed potential to deliver hydrophobic active substances. Graphical Abstract

Ethnopharmacological relevance: Caragana sinica (Buc'hoz) Rehd. is a plant widely grown in Yunnan, China, for both medicinal and edible purposes. The "National Compilation of Chinese Herbal Medicine" describes its nature as "slightly temperate and sweet". Caragana sinica is usually medicated with whole herbs, the main function is to replenish the kidneys and stop bleeding. Caragana sinica was used in folk medicine in Chuxiong, Yunnan, to treat deficiency colds, fatigue, fever, cough, hypertension, and other diseases. Aim of the study: This article investigates the structural characteristics of Caragana sinica polysaccharide (CSP) and explores its immune-regulatory activity and molecular biological mechanisms in cyclophosphamide-induced immunosuppressed mice, as well as its effects on intestinal bacteria. Methods: With the water-extraction and alcohol-precipitation method, Caragana sinica polysaccharide were extracted, obtaining CSP by purification. A variety of methods and techniques have been used to analyze the chemical properties and structural characteristics of CSP. Immunosuppressive mice model was established through intraperitoneal injection of cyclophosphamide (CTX) to study the immune-regulatory effects and mechanisms of CSP. Results: The data indicated that CSP is a neutral heteropolysaccharide mainly composed of arabinose and galactose. This article uses immunosuppressive mice induced by cyclophosphamide (CTX) as the model. The results showed that CSP can promote the immune function of CTX treated immunosuppressed mice and regulate the diversity and composition of intestinal microbiota. CSP can increase macrophage phagocytosis, NK cell killing activity, and lymphocyte proliferation activity. It can also repair the index and morphological damage of the thymus and spleen. And by binding to the TLR4 receptor, MyD88 was activated and interacted with TRAF6 to promote the transfer of NF-kappa B into the nucleus. Thereby promoting cytokine release and increasing the pro-duction of IL-1 beta, IL-6, IL-10, TNF-alpha, IgA, and IgG in the serum. CSP also effectively alleviated the liver damage caused by CTX through antioxidant activity. Furthermore, CSP can dramatically affect the intestinal microbiota and the body's immunity by boosting the relative presence of Bacteroides and Verrucamicrobiota. Conclusions: Research results indicated that CSP can regulate the immune function of mice, providing a basis for developing CSP as a potential immune modulator and functional food.

Musa basjoo Sieb polysaccharide (MBSP) is the active ingredient of Musa basjoo Sieb. The purpose of this study was to preliminarily characterize the structural properties of MBSP, and to explore its ameliorating effect LPS-induced macrophage RAW264.7 inflammation and its therapeutic effect on DSS-induced zebrafish colitis. The data indicated that the average molecular weight of MBSP was 393.4 kDa, which was an acidic heteropolysaccharide composed of seven monosaccharides. In the LPS-induced macrophage RAW264.7 inflammation model, we found that MBSP significantly reduced the level of inflammatory mediators (p< 0.001). The release of NO, IL-6, and TNF-α was reduced by 48.21%, 65.45%, and 86.49%, respectively. And MBSP modulated intracellular ROS levels. This might be related to the activation of NF-κB/MAPK signaling pathway by MBSP. Additionally, MBSP significantly improved the oxidative stress status of UC zebrafish. SOD, CAT, GSH-Px were increased by 50.58%, 39.07% and 65.86%, and MDA, MPO were decreased by 26.00% and 50.98%, respectively (p< 0.001). Meanwhile, MBSP was also found to be effective in improving UC by activating the TLR4/NF-κB/MAPK signaling pathway in vivo. In conclusion, the present study characterized the structural properties of MBSP from various aspects, confirmed the anti-inflammatory effect of MBSP in vitro, and further verified the in vivo anti-inflammatory activity of MBSP using UC zebrafish as an animal model. The results of this study provide a reference for the development and application of MBSP in the field of treating inflammatory diseases.

This study investigated the solubilizing capacity of glycosylated stevioside/hydroxypropyl-methylcellulose (stevia-G-HPMC) complexes with varying mass ratios on lutein. The impact on the steady-state flux and permeability coefficient of intracellular lutein was also explored through the construction of a Caco-2 cellular transport model. The results indicated that the equilibrium solubility of lutein linearly increased with an increase in stevia-G amount. The stability constants of the ternary system surpassed those of the binary system. Molecular dynamics simulation revealed a tight and stable structure in lutein supersaturated complexes. Meanwhile, lutein-stevia-G-HPMC complexes demonstrated superior cumulative penetrations, with the peak P-app (AP -> BL) value being (3.24 +/- 0.89) x 10(-5) cm.s(-1). There was a slight decrease in P-app (BL -> AP), which improved the forward transport of lutein. Highly soluble lutein in aqueous environments saturated the extracellular transport proteins on the AP side of cell membranes, thereby maintaining the high permeability transport. Notably, the permeability trend of lutein in Caco-2 cells negatively correlated with the equilibrium solubility and matched the single exponential growth model. When the mass ratio of lutein, stevia-G and HPMC was 1:21:5, the solubility-permeability trade-off of lutein was effectively maintained.

In this paper, the extraction process of burdock root polysaccharide was optimized using dynamic high pressure microfluidization (DHPM) combined with water extraction, and its infrared spectral structure and monosaccharide composition were analyzed to evaluate its scavenging activities against DPPH·, ·OH and ABTS＋· radicals. The results showed that the factors affecting the yield of burdock root polysaccharide were DHPM pressure>extraction temperature>liquid to solid ratio>extraction time> number of treatments in descending order. The optimal extraction conditions were determined by response surface methodology: DHPM pressure of 148.0 MPa, liquid-solid ratio of 25:1 mL/g, two times of treatment, extraction temperature of 63 ℃ and extraction time of 1 h. Under these conditions, the predicted yield of burdock root polysaccharide reached 29.6%, and the relative error between the actual yield of 29.7% and predicted values was only 0.3%. The polysaccharides were mainly composed of fructose, glucose, arabinose, galactose and glucosamine hydrochloride, with molar ratios of 0.844:0.122:0.024:0.008:0.002. The polysaccharides of burdock root had different effects on DPPH·, ABTS+· and ·OH radicals. The IC50 values were 0.30, 0.36 and 3.93 mg/mL, respectively. The study would provide a reference for the green and efficient extraction of burdock root polysaccharide.

为了提高叶黄素在功能食品及饮料应用中的稳定性,利用鹰嘴豆分离蛋白和甜菊苷为材料制备载叶黄素的复合体系,研究pH值、盐离子浓度、冻融处理、人工模拟胃肠液对鹰嘴豆分离蛋白-甜菊苷-叶黄素复合体系和鹰嘴豆分离蛋白-叶黄素复合体系稳定性的影响,以及复合体系在不同贮藏条件中的稳定性.结果表明,载叶黄素的鹰嘴豆分离蛋白-甜菊苷三元复合体系的耐盐性及耐酸性均高于载叶黄素的鹰嘴豆分离蛋白二元复合体系,且该三元复合体系在中碱性及低盐条件下的稳定性较好.冻融处理会破坏复合纳米颗粒结构,进而使体系失稳.贮藏温度对复合体系色泽的影响大于光照,复合体系适宜在4℃避光条件下贮藏.载叶黄素的鹰嘴豆分离蛋白-甜菊苷三元复合体系在胃肠液中的稳定性高于载叶黄素的鹰嘴豆分离蛋白二元复合体系,三元复合体系能更有效负载叶黄素而不被胃肠液中的消化酶降解.

In this paper, a lutein-glucosyl stevioside (stevia-G)-hydroxypropyl methylcellulose (HPMC) complex was prepared via an antisolvent precipitation combined with dynamic high pressure microfluidization method. The solubility, microstructure, crystallinity and thermodynamic properties of the freeze-dried powder were investigated, as well as the formation mechanism and the storage stability of the produced complex. When the optimal mass ratio of lutein, stevia-G, and HPMC was 1: 40: 0.5, the apparent solubility of lutein reached 2805.47 +/- 24.94 mu g.mL(-1), which was approximately 5600 times higher than that of lutein crystals. The lutein-stevia-G-HPMC complex formed an amorphous dispersed structure and was in a thermodynamically high energy state. The self-assembled micelle structure of stevia-G and HPMC polymer created a supersaturated system mainly by multiple hydrogen bonding, which promoted maximum lutein dissolving, delayed supersaturated crystallization process, and hindered precipitation. The present results suggested the complex formed by stevia-G and HPMC effectively promote lutein's hydrophilicity and stability.

The stability of carotenoids in puff-dried yellow peach powder during commercial storage under different water activity conditions was studied. The results showed that when the corresponding water activity was above 0.576, the loss of adsorbed water in yellow peach powder was closely related to the crystallinity of the amorphous sugar matrix. However, the adsorption isotherms confirmed by water absorption behavior, X-ray diffraction (XRD) pat-terns, and scanning electron microscopy did not clearly indicate this loss of adsorbed water. The content changes of individual carotenoids (lutein, zeaxanthin, β-cryptoxanthin, α-carotene, and β-carotene) during storage followed pseudo first-order kinetics, and the degradation of lutein and zeaxanthin occurred quickly over time. The stability of total carotenoids gradually increased when the water activity was less than 0.576, but the carotenoids degraded sharply when the water activity was between 0.753 and 0.843. The loss of carotenoids was related to the water absorption and crystallization of the sugar matrix in the powder.