Last Updated: 27 May 2022

“Egg yolk” is an important raw material of various kinds of food and Thai traditional dessert acting not only as a food stabilizer but also an emulsifier to hold together particles of immiscible liquid ingredients such as water and oil.  Preservation of egg yolk for longer shelf life and quality maintenance is highly important to food industry.  The synchrotron-related technique can be applied to evaluate the yolk shelf life and quality. 

Scientists of Synchrotron Light Research Institute (Public Organization)-SLRI           co-worked with a team of Kewpie (Thailand) Co., Ltd. to apply synchrotron light in infrared range to examine quality of the frozen modified egg yolk.  The scientists monitored the yolk stability and structural change of yolk protein such as change of functional groups, particle size consistency.  The lipid oxidation reaction which deteriorates unsaturated fatty acids or lipids was also monitored.

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 Figures of frozen egg yolk and processed food made of egg yolk

In this study, the unmodified egg yolk was used as a control to compare with egg yolk modified with the company’s EO and EN formulas. The scientists monitored change of protein structure and deterioration of fatty acid throughout 90-day storage at minus 20 degree Celsius. The result showed that change occurred to protein structure in the control while the modified yolk maintained its physical and chemical qualities.

The fatty acid deterioration affecting shelf life of frozen egg yolk occurred as well but at very small amount. Because of this, the scientists required infrared radiation from the synchrotron light source to study the main site where lipid oxidation reaction occurred. The data was later calculated using both kinetic reaction and Arrhenius equations to evaluate change of preserved yolk in quality at minus 20 degree Celsius.

The researcher group consists of SLRI scientists including Dr. Siriwan Nawong, the team leader, Dr. Phakkhananan Pakawanit, Mrs. Chunmanus Phoomalee, Ms. Siriporn Chaiyasit, and Ms. Nuttaya Pasornjaroenchai, together with a team of Kewpie (Thailand) Co., Ltd. The result is applied to evaluate quality of frozen egg yolk and will be further used in product research and development. This study is an example of applying synchrotron light to support private sector in product development.

Article by: 

Dr. Siriwan Nawong, Beamline Scientist 

Dr. Phakkhananan Pakawanit, Beamline Scientist