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Rheological characteristics of proanthocyanidin polymers from Pinus radiata . II. Viscoelastic properties of sequential alkaline extracts based on phenolic acid fraction
Author(s) -
Kim Seungrok,
Mainwaring David E.
Publication year - 1995
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/app.1995.070560805
Subject(s) - rheology , rheometry , pinus radiata , polyphenol , proanthocyanidin , aqueous solution , viscoelasticity , chemistry , polymer , fraction (chemistry) , viscosity , bark (sound) , organic chemistry , chemical engineering , chromatography , materials science , botany , composite material , antioxidant , engineering , physics , acoustics , biology
Steady and dynamic oscillatory rheometry were used to characterize two members of the plant polyphenols from Pinus radiata bark, water‐soluble proanthocyanidin polymers, and phenolic acids. The viscosity‐controlling factor of the extracts could be revealed by examining the various extracts under different chemical and rheological environments. Water extracted (100°C) bark was successively extracted with aqueous NaOH solutions of increasing alkalinity at 100°C and the rheological characteristics of the each fraction were examined in detail. The significant viscoelasticity of the 100°C aqueous NaOH sequential extracts suggests that this fraction can have a critical impact on the flow characteristics of overall extracts and arises from a major contribution of colloidal interactions involving the carbohydrate component. © 1995 John Wiley & Sons, Inc.