Degree Type

Dissertation

Date of Award

1989

Degree Name

Doctor of Philosophy

Department

Food Technology

First Advisor

Joseph G. Sebranek

Second Advisor

Patricia A. Murphy

Abstract

The effects of linearly increasing heating rates (17, 38 and 85°C/hr) and protein concentration (10, 20, 30, 40 and 50 mg/mL) on thermally induced gels made of extracted salt-soluble proteins were evaluated. Gel strength analyses indicated that the force needed to compress muscle protein gels decreased when heating rate was increased. A greater water loss from compressed gels occurred at protein concentrations of 10 and 20 mg/mL than at 30 to 50 mg/mL. Above 30 mg/mL, water loss tended to be relatively constant. Protein loss in the expelled water, after compression, was less for the slower heating rate, and larger as heating rate increased. The total amount of protein in the expelled water increased with increasing protein concentration in the system. SDS gel electrophoresis demonstrated a change in some of the expelled proteins at different heating rates.;Thermally induced protein gels were made using extracted salt-soluble proteins from stress susceptible pigs determined to be PSE. Effects of heating rates (17, 39 and 93°C/hr) at various protein concentrations (23, 34, 48 and 54 mg/ml) were evaluated. Gel strength of PSE extracts was 45% of the controls at gels from the first compression curve increased with increasing protein concentrations at all heating rates; however, gel strength was greater for slow heating rates than for fast heating rates in both PSE and normal samples. Percent water loss was greater for PSE extracts than for controls at the same protein concentration. Losses of 47% and 36% for PSE and controls, respectively, were observed at a protein level of 54 mg/ml protein. There was no heating rate effect on water losses in either case. Protein loss was lower, for both PSE and control, at low protein concentrations than at high protein content in the range studied. Slow heating rates resulted in less protein loss, for both PSE and control, while faster heating rates gave higher protein losses in the exuded water.;The effect of soy protein isolate (ISP) and sodium caseinate (SC) on thermally induced protein gels made of extracted salt-soluble porcine muscle proteins were studied. Effects of heating rates (17, 39 and 93°C/hr) at various protein concentrations (32, 43 and 54 mg/ml) were evaluated for interactions between meat and non-meat proteins. Gel strength of protein extracts with 2% ISP added was increased about 24%; when 2% SC was added gel strength increased about 70%. Water holding capacity of protein extracts was improved by 37% and 4% when 2% SC and 2% ISP were added, respectively.

DOI

https://doi.org/10.31274/rtd-180813-12258

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Juan Pedro Camou Arriola

Language

en

Proquest ID

AAI9014885

File Format

application/pdf

File Size

159 pages

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