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Structural characteristics of a highly branched and acetylated pectin from Portulaca oleracea L
- Source :
- Food Hydrocolloids. 116:106659
- Publication Year :
- 2021
- Publisher :
- Elsevier BV, 2021.
-
Abstract
- The water-extracted polysaccharide from Portulaca oleracea L. mainly consisted of two pectic polysaccharides designated as POWP-H and POWP-L. The POWP-L was rich in linear homogalacturonan with GalA content of 77.6%, while POWP-H might be a rhamnogalacturonan I (RG-I) pectin composed of Rha (15.7%), Ara (31.7%), Gal (42.5%) and GalA (10.1%). The structure of POWP-H was elucidated by partial degradation, methylation analysis combined with GC-MS method and NMR spectroscopy. It had a weight-average molecular weight of 1.2 × 106 g/mol and high degree of branch of 0.57. The presence of abundant arabinogalactan-II and certain galactan side chains in POWP-H was verified by the T-Araf (17.4%), 1,3,6-Galp (11.8%), 1,3-Galp (8.1%), T-Galp (13.4%) and 1,4-Galp (14.3%). The evidence for the RG-I backbone of POWP-H was demonstrated by the structure analysis of its degraded product POWP-H-H, which had the backbone of →4)-α-GalpA-(1 → 2)-α-Rhap-(1 → 4)-α-GalpA-(1 → 2,4)-α-Rhap-(1→ substituted by short side chain of β-Galp-(1 → 4)-β-Galp-(1→ at O-4 position of →2,4)-α-Rhap-(1 → . Moreover, the POWP-H-H was mainly O-acetylated at O-3 position of α-Rhap with 24.8% acetylation degree. In conclusion, POWP-H was mainly the highly branched and acetylated RG-I pectin with relative short RG-I backbone and abundant arabinogalactan II and certain galactan side chains. Besides, it adopted a flexible chain conformation in 0.1 M NaNO3 solution.
- Subjects :
- chemistry.chemical_classification
food.ingredient
010304 chemical physics
biology
Pectin
Chemistry
Stereochemistry
General Chemical Engineering
04 agricultural and veterinary sciences
General Chemistry
Nuclear magnetic resonance spectroscopy
Galactan
Portulaca
biology.organism_classification
Polysaccharide
040401 food science
01 natural sciences
chemistry.chemical_compound
0404 agricultural biotechnology
food
Acetylation
Arabinogalactan
0103 physical sciences
Side chain
Food Science
Subjects
Details
- ISSN :
- 0268005X
- Volume :
- 116
- Database :
- OpenAIRE
- Journal :
- Food Hydrocolloids
- Accession number :
- edsair.doi...........633f2bb8ef6d6edbdba160c11d6ded7b