Pectic polysaccharides from purple passion fruit peel: A comprehensive study in macromolecular and conformational characterizations

Rui Guo; Sen Tian; Xujiao Li; Xuejiao Wu; Xin Liu; Deshun Li; Yanfang Liu; Lianzhong Ai; Zibo Song; Yan Wu

doi:10.1016/j.carbpol.2019.115406

Pectic polysaccharides from purple passion fruit peel: A comprehensive study in macromolecular and conformational characterizations

Carbohydr Polym. 2020 Feb 1:229:115406. doi: 10.1016/j.carbpol.2019.115406. Epub 2019 Oct 3.

Authors

Rui Guo¹, Sen Tian¹, Xujiao Li¹, Xuejiao Wu¹, Xin Liu¹, Deshun Li², Yanfang Liu², Lianzhong Ai³, Zibo Song⁴, Yan Wu⁵

Affiliations

¹ Shanghai Engineering Research Center of Food Safety, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China.
² Institute of Edible Fungi, Shanghai Academy of Agricultural Sciences, Key Laboratory of Edible Fungi Resources and Utilization (South), Ministry of Agriculture, National Engineering Research Center of Edible Fungi, National R&D Center for Edible Fungi Processing, Shanghai 201403, China.
³ School of Medical Instrument and Food Engineering, University of Shanghai for Science and Technology, Shanghai 200093, China.
⁴ Yunnan Maoduoli Group Food Co., Ltd., Yuxi 653100, China.
⁵ Shanghai Engineering Research Center of Food Safety, School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai 200240, China. Electronic address: wuy@sjtu.edu.cn.

PMID: 31826397
DOI: 10.1016/j.carbpol.2019.115406

Abstract

A polysaccharide (PFPP) from purple passion fruit peel was optimally extracted, with the highest yield (10.05%, w/w) obtained under 35 °C extraction temperature, 240 W ultrasonic power, 65:1 mL/g liquid-to-solid ratio, 0.6% (w/v) ammonium oxalate, 30 min extraction time and pH 2.0. According to composition analyses, pectic PFPP and its fractions (PFPP-10, -15 and -20) were revealed as linear homogalacturonans interrupted by rhamnogalacturonan I in different lengths and extensities, where low esterification degrees (35.35-39.66%) were indicated via FT-IR. Furthermore, based on macromolecular models, comprehensive analyses on macromolecular and conformational characterizations of PFPP fractions were conducted quantitatively through, e.g., shape factor (1.42-1.79), Mark-Houwink-Sakurada exponent (0.55-0.74), conformational power-law exponent (0.52-0.58), fractal dimension (1.72-1.94) and persistence length (6.73-13.47 nm). Therefore, different semi-flexible coil conformations were proposed schematically, where lower molecular-weight PFPP fractions were less flexible. This could provide a molecular basis for precise re-utilizations of PFPP in food and pharmaceutical industries.

Keywords: Conformational behavior; Macromolecular dimension; Passiflora edulis Sims f. edulis; Pectic polysaccharides; Purple passion fruit peel; Ultrasonic-aided ammonium oxalate extraction.