Identifier

etd-07042017-112218

Degree

Master of Science (MS)

Department

School of Nutrition and Food Sciences

Document Type

Thesis

Abstract

Dehydration is a good approach for egg preservation. However, dried egg products may still suffer from deterioration if stored in an abused temperature environment or prolonged times. Storage conditions can induce undesirable reactions and loss of functionality and quality. The objective of this study was to evaluate the physicochemical characteristics and functionality of spray dried egg yolk powders, which included plain whole egg (PLWE), free flow yolk (FFY), enzyme modified yolk (EMY), and free flow whole egg (FFWE) stored at 4 °C, 25 °C, 43 °C or 54 °C, over a 2-month period; and provide useful suggestions to maximize quality when used in the food industry. Functionality and physicochemical tests included solubility index, emulsifying stability, viscosity and heat stability of emulsions, free fatty acid levels, lipid hydro peroxides, color change, and morphological appearance. Solubility Index results indicated that FFWE was the most soluble sample followed by PLWE, EMY, and FFY. Emulsion stability results revealed that EMY formed the most stable emulsion followed by FFWE, FFY, and PLWE. Free fatty acid levels indicated that EMY deteriorated faster, followed by FFWE, FFY, and PLWE. Lipid hydro-peroxides were most abundant in EMY followed by FFY, PLWE, and FFWE. Total color change was highest for FFY, followed by PLWE, EMY, and FFWE. All samples passed the heat test after 1 month at storage but failed after 2 months of storage at all temperatures. The morphology of the egg powder particles revealed that high processing temperatures increased porosity which resulted in greater oxidation and storage time induce agglomeration of the egg powders. Overall, physicochemical changes found during the storage of dried egg powders were more evident at 43 °C or 54 °C. Lipid oxidation was responsible for the decrease in quality of dried egg powders. Therefore, mostly effective approaches are required to prevent oxidation reactions. Adjusting the storage temperature and humidity, and using an effective packaging method with an oxygen barrier is strongly suggested.

Date

2017

Document Availability at the Time of Submission

Secure the entire work for patent and/or proprietary purposes for a period of one year. Student has submitted appropriate documentation which states: During this period the copyright owner also agrees not to exercise her/his ownership rights, including public use in works, without prior authorization from LSU. At the end of the one year period, either we or LSU may request an automatic extension for one additional year. At the end of the one year secure period (or its extension, if such is requested), the work will be released for access worldwide.

Committee Chair

Losso Jack

DOI

10.31390/gradschool_theses.4583

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