A diffusing wave spectroscopy study of the dynamics of interactions between high methoxyl pectin and sodium caseinate emulsions during acidification
- 作者：Jinru Liu ; Milena Corredig ; Marcela Alex ; er
- 关键词：Diffusing wave spectroscopy ; High methoxyl pectin ; Sodium caseinate emulsion ; Destabilization
- 刊名：Colloids and Surfaces B ; Biointerfaces
- 出版年：2007
- 期刊代码：14_09277765
- 类别：ms
- 出版时间：1 October 2007
- 卷：59
- 期：2
- 页码：164-170
- 文件大小：390 K
摘要
A non-invasive technique, diffusing wave spectroscopy (DWS), and traditional dynamic light scattering (DLS) were used to study the interactions of high methoxyl pectin (HMP) with sodium caseinate-stabilized emulsion droplets. At pH 6.8, the droplet size measured by DLS did not change as a function of HMP concentration (up to 0.3%). However, the droplet diameter measured by DWS kept relatively constant up to 0.07%HMP after which it showed drastic increases. The turbidity parameter 1/l* decreased with HMP concentration and levelled off at 0.07%HMP, indicating that the system underwent reorganization and reached equilibrium at 0.07%HMP. During acidification at pH 5.4, right before the pH of aggregation of control emulsions, all emulsions containing 0.05–0.2%HMP showed an increase of 1/l*. This increase indicated the interaction of HMP with sodium caseinate at the interface. Emulsions containing 0.05 and 0.1%HMP also showed destabilization, and the pH of destabilization depended on the concentration of HMP. Sufficient amounts of HMP (0.2%) stabilized the caseinate-coated oil droplets, and the mean square displacement slope was close to 1 throughout, indicating free diffusion of emulsion droplets.