Date of Award

1990

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

School of Nutrition and Food Sciences

First Advisor

Thomas C.-Y. Hsieh

Abstract

Volatile compounds from two protein-rich foods, crabmeat and eggs, were studied with emphasis on qualitative and quantitative determination of a wide variety of chemical substances including degradation compounds from amino acids, lipids and carboyhdrates as well as compounds derived from the packaging material and the environment. Boiled and pasteurized blue crab (Callinectes sapidus) meat samples were analyzed for volatile flavor components by dynamic headspace sampling, capillary column gas chromatography and mass spectrometry. Fifty-three volatile compounds were identified in crabmeat samples. Levels of volatile compounds in both samples were compared and it was found that the boiled crabmeat contained higher levels of most compounds. Thirty-eight volatile compounds were identified in scrambled eggs. Selected compounds were quantified. Aldehydes were the most abundant volatile compounds in the egg samples. Volatile styrene monomer increased in scrambled egg samples during a two-week storage of shell eggs in a polystyrene container. Scrambled eggs prepared from a batch of supermarket shell eggs contained 7 times more ethylbenzene and styrene than those prepared from a batch of fresh farm eggs stored in a polystyrene container for two weeks. A USDA method of dynamic headspace sampling/gas chromatography was evaluated and used to quantify dimethyl sulfides as potential quality markers in liquid whole egg samples. Percent acceptance (0, 20, 40, 60, 80, or 100%) by a panel of five USDA egg inspectors on an experimental batch of samples generally decreased with increasing dimethyl sulfide (DMS) concentration (0 to 540 ng/g) in the samples. In addition, dynamics of DMS and dimethyl disulfide (DMDS) formation during egg spoilage were investigated. It was found that egg decomposition may follow different paths and that DMS concentration may not be indicative of the extent of spoilage in a sample. This study used a relatively low-artifact analytical approach to generate objective information on flavor quality of selected protein-rich foods. Further investigation into the interaction of the critical volatile compounds with the food matrices as well as packaging and/or the environment may provide critical information to facilitate improvement of the flavor quality of the foods.

Pages

104

Share

COinS