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Green tea residues are the by-product of tea processing and they contain a large number of bioactive ingredients. Steam explosion has been recognized as one of the most innovative pretreatments for modifying the physicochemical characteristic of polysaccharides from lignocellulosic materials. However, the comparison of biological activity of steam exploded (SE-GTR) and unexploded (UN-GTR) green tea residue polysaccharides was still unclear, which prompted the determination of the efficacy of steam explosion in tea residue resource utilization. In this study, the effects of two extracted polysaccharides UN-GTR and SE-GTR on human gut microbiota in vitro fermentation were conducted. The results showed that after steam explosion pretreatment, SE-GTR displayed more loose and porous structures, resulting in higher polysaccharide content (2483.44±0.5 μg/mg) compared to UN-GTR (1903.56±2.6 μg/mg). In addition, after 24 h fermentation, gut microbiota produced more beneficial metabolites by SE-GTR. The largest SCFAs produced among samples was acetic acid, propionic acid and butyric acid. Furthermore, SE-GTR could regulate the composition and diversity of microbial community, increasing the abundance of beneficial bacteria, such as Bifidobacterium. These results revealed that steam explosion pretreatment could be a promising and efficient approach to enhance the antioxidant activity and bioavailability of polysaccharides isolated from tea residues., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Chitosan was prepared by alkaline N-deacetylation of β-chitin from squid pens, and N-(2-hydroxy) propyl-3-trimethyl ammonium chitosan chloride (HTCC) derivatives, with different degrees of quaternization (DQ) ranging from 0.77 to 1.06, were synthesized. It was identified by FT-IR, 1H NMR and XRD analysis. All of the HTCC showed good water solubility in a wide pH range. The moisture absorption and retention abilities of all the HTCC were much better than that of the chitosan. The moisture absorption and retention values of all the HTCC at 43% RH for 24 h were above 49% and 92%, respectively. The scavenging ability of HTCC against hydroxyl and ABTS radicals improved with increasing concentration. The effectiveness of HTCC against hydroxyl radicals was lower than that of chitosan. These results indicated that HTCC, which has a much better moisture absorption and retention capacity, may act as a potential moisturizer in vitro., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Effects of extraction temperature, extraction time and ratio of water to material as well as their interactions on the yield of total polysaccharide from Herba lophatheri were studied by response surface methodology (RSM). The optimal conditions for the extraction of polysaccharides were determined to be the ratio of liquid to solid of 39.01, extraction time of 2.11h and extraction temperature of 97.09°C. Under these optimal conditions, the yield of polysaccharides obtained was 5.73±0.10%, which was well matched with the value predicted by the model. In vitro antioxidant assays showed that the polysaccharides HLP possessed significant inhibitory effects on superoxide radical. It also exhibited strong 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, hydroxyl radical scavenging activities and its reducing power, ferrous ions chelating effect was also strong. These results suggested that H. lophatheri polysaccharides could be a suitable natural antioxidant and may be the functional foods for humans., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Chitosan was prepared by alkaline N-deacetylation of β-chitin and hydroxypropyl derivatives with different degrees of substitution (DS) were synthesized. It was characterized by Fourier transform infrared (FT-IR) and elemental analysis. The DS of hydroxypropyl chitosan (HPCS) calculated by an element analyzer were 0.42, 0.75, 1.20, 1.82 and 2.25. HPCS showed better foam capacity and stability than that of chitosan, and the effectiveness correlated well with the DS of HPCS. The highest bile acid-binding capacity of all five HPCS reached 56.02 mg/g, which was 4.0-fold higher than that of chitosan. The scavenging ability of HPCS against hydroxyl and ABTS radicals improved with increasing concentration. The correlation between the hydroxypropyl content (DS) of HPCS and scavenging ABTS radical ability was positive. The hydroxyl radicals scavenging activity of HPCS correlated well with its increasing concentration, and EC50 values were below 12.5 mg/mL. These results indicated that hydroxypropylation is a possible approach to obtain chitosan derivatives with desirable physiochemical properties., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Four polysaccharides (BLF80-A, BLF80-B, BLF80-C and BLF80-D) were isolated by hot-water extraction and purified from the leaves of Herba Lophatheri by DEAE-Sepharose fast flow. Their chemical and physical characteristics were determined and antioxidant activities were investigated on the basis of DPPH radical assay, hydroxyl radical assay and superoxide radical assay. The results showed that four polysaccharides exhibited antioxidant activities in a concentration-dependent manner, and the higher molecular weight, the stronger antioxidant activities of polysaccharides. Besides, the monosaccharide compositions of polysaccharides also influence their antioxidant activities. BLP80-D showed the strongest scavenging ability, followed by BLP80-C, BLP80-B and BLP80-A., (Copyright © 2013 Elsevier B.V. All rights reserved.)

The objective of this study was to evaluate in vitro antioxidant capacities of polysaccharides extracted from Moso Bamboo-Leaf (BLP). The molecular weight of the polysaccharides were obtained by SEC-LLS and their molecular masses were 13.4×10(4)Da, 2.8×10(4)Da and 1.9×10(4)Da, respectively. Available data obtained with in vitro models suggested WB1 (precipitated by 30% ethanol) showed significant inhibitory effects on superoxide radical, hydroxyl radical, DPPH radical and ferrous metal-chelating capacities. These results clearly establish the possibility that polysaccharides extracted from Moso Bamboo-Leaf could be effectively employed as ingredient in health or functional food, to alleviate oxidative stress., (Copyright © 2013 Elsevier B.V. All rights reserved.)