Viscometric behavior of high-methoxy and low-methoxy pectin solutions

• Published in: Food hydrocolloids 2006, Vol.20 (1), p.62-67
• Main Authors: Yoo, Sang-Ho, Fishman, Marshall L., Hotchkiss, Arland T., Lee, Hyeon Gyu
• Format: Article
• Language: English
• Subjects: aggregate stability; aqueous solutions; Biological and medical sciences; chemical structure; Food additives; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; General aspects; High-methoxy pectin; Intrinsic viscosity; Low-methoxy pectin; Pectin aggregation; pectins; protein aggregates; Reduced viscosity; rheological properties; salt concentration; viscometers; viscosity
• ISSN: 0268-005X; 1873-7137
• DOI: 10.1016/j.foodhyd.2005.03.003

The hydrodynamic behavior of high-methoxy (HM) and low-methoxy (LM) pectin solutions was examined by capillary viscometric analysis. The LM-pectin was produced from the HM-pectin by PME-deesterification. As a result of the viscometric analysis, the PME-deesterified LM-pectin showed quite different solution behavior from the HM-pectin. The LM-pectin had larger intrinsic viscosity ([ η]) than HM-pectin when dissolved in 0.005 and 0.05 M concentrations of monovalent salts whereas HM-pectin had a higher value of [ η] when dissolved in 0.2 M salt than LM-pectin. The concentration dependence of HM-pectin η red values was fairly constant, whereas the concentration dependence of LM-pectin η red values had a tendency to decrease as the pectin concentration approached zero. The effect of salt-type on the hydrodynamic behavior of both HM- and LM-pectin solutions was almost negligible. The precipitous drop in LM-pectin [ η] upon increasing the salt concentration from 0.05 to 0.2 M is interpreted as arising from its disaggregation. This interpretation is based in part on data from HPSEC with online light scattering and viscosity detection.