Physicochemical and Functional Properties of Okra Leaf Polysaccharides Extracted at Different pHs

Ibukunoluwa Fola Olawuyi, Jong Jin Park, Dongyup Hahn, Won Young Lee

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Different extraction pH values obtain polysaccharides with tailored structures and novel functionalities. This study investigated the influence of different extraction pH values (4.2, 6.8, and 9.2) on the physicochemical compositions and structural and functional properties of okra leaf polysaccharides (OLPs). The extraction yield (2.74–7.34%), molecular weights (68.5–85.4 kDa), total sugar contents (64.87–95.68%), degree of acetylation (18.28–22.88%), and methylation (8.97–15.20%) of OLPs varied significantly (p < 0.05). The monosaccharide composition reflected OLPs as pectic polysaccharides, with varied compositions of galacturonic acid, galactose, rhamnose, and arabinose. However, the differences in their sugar molar ratios, such as their side-chain and backbone chain compositions, greatly affected their functional properties. Additionally, notable differences due to extraction pH were observed in physical properties, thermal stability, and crystallinity. However, FTIR and NMR spectra revealed that extraction pH had negligible effects on the primary structure of OLPs. All OLPs showed non-Newtonian fluid behavior in the aqueous system with different apparent viscosities correlating with their molecular weights. Furthermore, the OLPs fractions stabilized oil-in-water emulsions differently and had distinct radical scavenging activities related to their compositions. This study provides a basis for selecting appropriate extraction pH to prepare OLPs with specific characteristics and applications in food-related disciplines.

Original languageEnglish
Pages (from-to)405-418
Number of pages14
JournalChemistry (Switzerland)
Volume4
Issue number2
DOIs
StatePublished - Jun 2022

Keywords

  • extraction
  • functionalities
  • okra leaf
  • pH
  • polysaccharides

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