Degree Type

Dissertation

Date of Award

1995

Degree Name

Doctor of Philosophy

Department

Food Science and Human Nutrition

First Advisor

Earl G. Hammond

Abstract

The flavor of Swiss cheese made from various natural and synthetic fats was compared with cheese made from the natural milk emulsion. Cheeses made from recombined milk fat and skim milk with or without the addition of gum acacia gave typical flavor similar to the natural milk emulsion. Homogenization did not have an effect on flavor of the cheese. Cheese made from recombined milk fat and skim milk plus buttermilk solids had lower typical flavor than the natural milk emulsion or cheeses made with gum acacia. Cheeses made from high-oleate sunflower oil with or without the incorporation of synthetic short-chain fatty acids gave the lowest typical flavor. Cheeses made with high-oleate sunflower oil with the incorporation of natural short-chain fatty acids gave slightly better flavor. All cheeses had flavor that was acceptable to panelists;Fat content of the recombined cheeses was slightly lower than controls. pH of all cheeses varied, and was below normal. Moisture content was within normal range. Production of acetic and propionic acids was normal, indicating that normal fermentation had occurred. Proteolysis varied, with the highest levels occurring in cheeses made from the natural emulsion, milk fat, or high-oleate sunflower oil modified by natural short-chain fatty acids;Cheeses with the poorest flavor tended to have the lowest levels of short-chain fatty acids. The fat-aqueous interface seems to play a role in encouraging lipolysis. Minor short-chain fatty acids were tentatively identified in the cheeses. Short-chain fatty acids are critical to good flavor development in Swiss cheese;A model was developed to predict the flavor variability of these cheeses by chemical and physical analyses. A factor composed of proteolysis, fat content, long-chain free fatty acids, and acetic acid predicted 42% of the flavor variability of these cheeses. A second factor consisting of the short-chain fatty acids plus oleic acid was correlated with the first factor, but its contribution to the model was not significant;An improved method for determination of dicarbonyls produced by microorganisms in culture was developed. Five millimolar sodium oleate added to the culture broth did not inhibit growth or dicarbonyl production by Lactobacillus bulgaricus.

DOI

https://doi.org/10.31274/rtd-180813-10215

Publisher

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

Copyright Owner

Firth Kraft Whitehouse

Language

en

Proquest ID

AAI9611002

File Format

application/pdf

File Size

92 pages

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