② Polyunsaturated fatty acids(PUFAs )-enriched fish oils
1. Medical and nutritional aspects of marine oils have received widespread attention
2. Fish oils contain triacylglycerides and variable range of highly unsaturated long-chain fatty acids,
with the number of carbon atoms ranging from 14 to 22
3. PUFAs are essential components in human nutrition
4. An appropriate ratio of n-3/n-6 PUFAs is 1:4 must be in the diet of human being
5. Most fish oils contain only moderate levels of EPA and DHA
6. There is a great commercial interest in preparing PUFA-enriched fish oil
⑴ Winterization
⑵ Molecular distillation
⑶ Solvent crystallization
⑷ Chemical methods - supercritical fluid extraction, complexing with urea, chromatography (HPLC)
7. Mild enzymatic modification processes
⑴ Lipase(triacylglycerol acylhydrolase, EC 3.1.1.3),
- Lipases catalyze the reverse reaction: ester synthesis and interestrification