Our objective in this study is to assess the safety of docosahexaenoic acid (DHA) fortified milk of dairy cows fed feeds containing protected fish oil treated with formaldehyde by analyzing formaldehyde concentration in commercial milk and DHA fortified milk of dairy cows fed formaldehyde treated feed. There are 3 milk samples in this study: Commercial milk (CM), DHA fortified milk for Kid (DHA-K) and DHA fortified milk for Baby (DHA-B). We confirm the fresh quality of these three samples by physicochemical tests. In fat content result, three groups are significantly different at the p < 0.05 by Duncan's multiple range test, but fat content of group DHA-K is about half the level of the other two groups. Protein content of group DHA-K is 1% higher than other two groups. According to the analysis result of DHA content of DHA fortified milk, DHA content of DHA-B is two-fold higher than DHA-K. Similar pattern was seen in the intake based on age. According to HPLC analysis result of formaldehyde concentration in milk, commercial milk and DHA fortified milk are between 0.013 ppm and 0.057 ppm which is formaldehyde standard level in fresh milk settled in WHO (World Health Organization). Three groups have no significantly differences at the p < 0.05 by Duncan’s multiple range test. For this reason, it can be concluded that there is no transition of formaldehyde from dairy cows fed formaldehyde treated feeds to its produced milk. Safety about formaldehyde of DHA fortified milk of dairy cows fed formaldehyde treated feeds is considered similar to commercial milk.

It was tested the possibility that EPA and DHA could be separated from fish oil fatty acid ethyl ester(FAEE) in the supercritical carbon dioxide rectification method. Experiments were carried out in the 1800mm tall and temperature gradient packed rectification column at the pressure of 100bar and carbon dioxide flow rate of 52.43NL/min. Experimental results showed that this method was useful to separate the FAEE by the relative volatility of the components. The maximum attainable concentration of EPA, DHA and both of them in product were 41%, 43% and 57% respectively in this rectification column using raw fish oil feed.

Separation of EPA and DHA from fish oil fatty acid ethyl ester (FAFE) by urea adductive crystallization method was carried out in the supercritical carbon dioxide (SC CO2) as a solvent. Our results showed that SC CO2 is a good candidate as a solvent in the urea adductive crystallization to separate FAFE by the number of unsaturated bonds. Compared to the separation process using methanol. SC CO2 yielded better performance in the overall selectivity of EPA and DHA. The effect of process variables on separation of EPA and DHA was discussed in detailed. A hybrid technology of SC CO2 fractionation and urea adductive crystallization with SC CO2 was conformed as a viable process to separate and concentrate EPA and DHA from fish oil.