Manufacturing of Egg Yolk Oil from Egg Yolk with Acid Protease Preparations

Abstract

In order to obtain egg yolk oil by a method other than roasting, interactions between lipids and proteins in the egg yolk were split off by partial hydrolysis with acid protease preparations i. e. Kokurase SS (reaction: 50°C, 3h), and addition of glacial acetic acid followed by heatirlg at 100°C for 10min. After centrifugation, the sum total of the separated oil and the same amount of water was transferred to a separating funnel and then shaken vigorously several times in order to remove the odor of acetic acid. The yolk oil obtained in this way was light yellowish and not as viscous as that obtained by roasting of egg yolk. The yield of yolk oil was about 20-23%. The fatty acid composition of the separated yolk oil was found to have a higher content of linoleic, linolenic and arachidonic acids than yolk oil obtained by roasting. The vitamine E content of yolk oil was found to be about 3.4-4.3 times higher than that of egg yolk.