Extraction and structural identification of alkali-soluble polysaccharides of longan (Dimocarpus longan Lour.) fruit pericarp
Guoxiang Jiang, K. Nagendra Prasad, Yueming Jiang, Bao Yang, Yongxia Jia and Jian Sun
Innovative Food Science & Emerging Technologies, Volume 10, Issue 4, October 2009, Pages 638-642
2009
บทคัดย่อ
Two alkali-soluble polysaccharide fractions (ASPs I and II) were extracted from longan fruit pericarp in this work. The results of chemical composition indicated that ASP I and II fractions comprised mainly of polysaccharides, proteins and lignins. Four monosaccharides, namely Xyl, Ara, Glc and Gal, were identified for both ASPs I and II. Xyl was the dominant monosaccharide in the two alkali-soluble polysaccharides with relative molar percentages of >60%. It constructed the backbone in combination with Ara for both ASPs I and II. The analysis of glycosidic linkage indicated that Xyl had two linkages,3)-Xyl-(1and 3, 4)-Xyl-(1. The substitution at C-4 position indicated that Xyl was of pyranose structure. The infrared spectra of ASPs I and II showed the characteristic bands at approximate 897 cm−1which indicated the β-linkage configuration of Xyl.