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Ultrasonic extraction, structural characterization, physicochemical properties and antioxidant activities of polysaccharides from bamboo shoots (Chimonobambusa quadrangularis) processing by-products

Chen, Guangjing, Bu, Fan, Chen, Xuhui, Li, Changfeng, Wang, Shasha, Kan, Jianquan
International journal of biological macromolecules 2018 v.112 pp. 656-666
2,2-diphenyl-1-picrylhydrazyl, Chimonobambusa, antioxidant activity, bamboo shoots, byproducts, differential scanning calorimetry, experimental design, gel chromatography, glycosidic linkages, hydroxyl radicals, loss modulus, molecular weight, oils, polysaccharides, raw materials, rheology, storage modulus, temperature, thermal stability, thermogravimetry, ultrasonics, viscoelasticity, water holding capacity
In this study, a novel polysaccharide (PCPs) was obtained from bamboo shoots (Chimonobambusa quadrangularis) processing by-products through the ultrasonic-assisted extraction (UAE) and Sephadex G-100 size-exclusion chromatography purification. By using a Box–Behnken design (BBD) to optimize the parameters for extracting the crude PCPs with UAE, the maximum yield of crude PCPs (8.76%) was obtained under the optimal extraction conditions as follows: ratio of water to raw material 20.2mL/g, extraction temperature 49°C, ultrasonic power 240W, and extraction time 40min. Structurally, PCPs was identified as hetero-polysaccharides, which was composed of Man, Rha, GlcA, GalA, Glc, Gal, Xyl, and Ara in a molecular ratio of 1.00:2.05:2.28:2.36:15.76:49.06:16.70:39.86. The molecular weight distribution analysis showed that PCPs had three components with molecular weights of 136.1, 29.7 and 8.3kD, respectively. The glycosidic linkage analysis showed that PCPs contained 1→or 1→6 glycosidic linkages (35.1%), 1→2 or 1→4 glycosidic linkages (14.8%), and 1→3 glycosidic linkages (50.1%). conformations. The obtained results revealed that PCPs with a semi-crystalline structure exhibited important functional properties including the repose angle, swelling index (SC), water retention capacity (WRC), and oil retention capacity (ORC). The viscoelastic property of PCPs system exhibited a gel-like behavior with storage modulus G′ always being higher than loss modulus G″. PCPs displayed excellent thermal stability as assessed by rheology and TGA/DSC. Furthermore, PCPs exhibited good chemical antioxidant activities in DPPH, ABTS and hydroxyl radical scavenging abilities, and metal chelating activity.