Viscoelastic behaviour of mixtures of locust bean gum and pectin dispersions

• Type: Article in International Scientific Journal
• Date: 1993

Authors

J. Silva (Author) Other; Maria do Pilar Gonçalves (Author) FEUP; M. Rao (Author) Other

Journal

Title: Journal of Food Engineering

No. 18

Pages: 211-228

ISSN: 0260-8774

Publisher: Elsevier

Scientific classification

FOS: Engineering and technology > Other engineering and technologies

Other information

Resumo (PT): Viscoelastic properties of single-component systems - locust bean gum (LBG), high-methoxyl (HMP) and low-methoxyl (LMP) pectins - and of HMP/LBG and LMP/LBG blends, were studied using dynamic oscilla-tory and steady-shear methods. The mechanical spectra of HMP/LBG blends showed characteristics intermediate between the individual components. A possible weak antagonistic interaction was found between LMP and LBG, especially in the mixture with similar amount of each single-component solation. Correlation between dynamic and steady-shear viscosities was compared with the empirical rule of Cox and Merz. Departures from the Cox-Merz rule were observed for the HMP disper-sions, whereas for the LMP and the LBG dispersions the Cox-Merz rule prediction was satisfactory. The different behaviour of LMP relative to the HMP dispersions can be attributed to the lesser extent of intermolecular association and higher hydrodynamic volume, due to the higher charge density.

Abstract (EN): Viscoelastic properties of single-component systems - locust bean gum (LBG), high-methoxyl (HMP) and low-methoxyl (LMP) pectins - and of HMP/LBG and LMP/LBG blends, were studied using dynamic oscilla-tory and steady-shear methods. The mechanical spectra of HMP/LBG blends showed characteristics intermediate between the individual components. A possible weak antagonistic interaction was found between LMP and LBG, especially in the mixture with similar amount of each single-component solation. Correlation between dynamic and steady-shear viscosities was compared with the empirical rule of Cox and Merz. Departures from the Cox-Merz rule were observed for the HMP disper-sions, whereas for the LMP and the LBG dispersions the Cox-Merz rule prediction was satisfactory. The different behaviour of LMP relative to the HMP dispersions can be attributed to the lesser extent of intermolecular association and higher hydrodynamic volume, due to the higher charge density.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 18