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item Onwulata, Charles

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/18/2004
Publication Date: 1/22/2005
Citation: Onwulata, C.I. 2005. Melt temperature models of extruded whey proteins. (abstract). AOCS Ann. Mtg. & Expo. Paper No. 8043.

Interpretive Summary: N/A

Technical Abstract: Empirical models of corn meal extrudates with whey protein isolate (WPI) based on melt temperature (MT) were derived for high shear extrusion conditions with temperatures ranging from 100 to 150C, ramped at 5 C intervals. WPI was added to corn meal at concentrations of 15, 25 and 35 wt%. Adding WPI to corn meal increased MT and produced two types of temperature-dependent extrudate: low temperature, high density and strong extrudate, or high temperature, low density and brittle extrudate. There was a significant (p<0.05) increase in melt temperature (MT) and moisture flash off due to adding WPI; substituting WPI in excess of 25 wt% resulted in unstable extrusion charring. Extrudates were denser and less porous at melt temperatures below 125C. However, above 130C, density decreased, resulting in crispier, easy-to-break extrudates, with densities below 0.8 g/cm3. Quality attributes of WPI co-extrudates were better correlated with MT (R2=0.95) than with specific mechanical energy, SME (R2=0.85).