Submitted to: Food Hydrocolloids Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 11/20/2004
Publication Date: 8/10/2005
Citation: Yoo, S., Fishman, M.L., Hotchkiss, A.T., Lee, H. 2005. Viscometric behaviors of high-methoxy and low-methoxy pectin solutions. Food Hydrocolloids Journal. 20:p.62-67. Interpretive Summary: The need to increase utilization of low valued co-products derived from the processing of fruit has prompted us to investigate the solution viscosity of pectin. Pectin is a polysaccharide found in citrus fruit. In this work we show that the solution viscosity of 'natural'and chemically modified pectin is quite different in the presence of added salt. This information could be important in understanding its functional properties when incorporating pectin in processed foods. This research should be of help to food processors in formulating food ingredients containing pectin and salt.
Technical Abstract: The hydrodynamic behaviors of high-methoxy (HM) and low-methoxy (LM) pectin solutions were 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 ([n]) than HM-pectin when dissolved in 0.005M and 0.05M concentrations of monovalent salts whereas HM-pectin had a higher value of [n] when dissolved in 0.2M salt than LM-pectin. The concentration dependence of nred values of HM-pectin was fairly constant whereas the concentration dependence of nred values of LM-pectin had a tendency to decrease as 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 [n] upon increasing the salt concentration from 0.05 to 0.2M of LM-pectin is interpreted as arising from its disaggregation. This interpretation is based in part on data from HPSEC with online light scattering and viscosity detection.