Submicron O/W emulsions embedded into modified waxy maize starch based matrix: rheological and microstructural characterization

A H ALFANO; T CROSTA; MARIA JULIA MARTÍNEZ; OSCAR E PÉREZ; MARÍA EDITH FARÍAS

FOOD HYDROCOLLOIDS

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2017 vol. 67 p. 120 - 129

0268-005X

The aim of this study was to investigate the rheological properties and storage stability of submicron O/W emulsions formulated with dried skim milk and vegetable oil at neutral pH, and to analyse the impact of their inclusion into starch suspension. Sunflower oil droplets were pre-emulsified in skim milk suspension by a rotor-stator homogenizer and further an ultrasonic treatment was applied. Droplets sizes decreased after applying ultrasound (US) from 1.4 to 0.4 m (d32). Flocculation may be responsible for the increase in viscosity with aging time, being the second the predominant one. Mixed colloidal suspensions (submicron emulsions embedded into starch matrix) showed shear-thinning behaviour. Over storage, light microscope micrographs suggested deposited droplets on the starch granules surface. Flow and viscoelastic behaviour of mixed colloidal suspensions indicated droplets flocculation, attributable to a reversible depletion mechanism of destabilization.