Impact of extrusion on swelling power and foam stability in mixtures of corn starch and whey protein isolate as a model system
This study examines the impact of an extrusion process on the swelling power (SP) and the foaming stability (FS) of mixtures of corn
starch (CS) and whey protein isolate (WPI). A single-screw extruder was operated with a speed of 200 rpm, feed rate of 100 g/min,
extrusion temperature of 140ºC, and initial moisture content of 20%. The results show that the extrusion process significantly increased
the SP of the CS/WPI mixtures at each of the heating temperatures evaluated (60, 70, 80, and 90ºC). Furthermore, a significant increase
in SP was observed with the increase in temperature in most of the mixtures. The extrusion only slightly affected the foam stability of
the mixtures. The results show the importance of extrusion on the interactions between CS and WPI.