Enzymatic incorporation of docosahexaenoic acid into borage oil

• Published in: Journal of the American Oil Chemists' Society
• Main Authors: Namal Senanayake, S. P. J., Shahidi, Fereidoon
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1999
• Subjects: Rugosa; Antarc*; Antarctica
• Online Access: http://dx.doi.org/10.1007/s11746-999-0197-x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1007%2Fs11746-999-0197-x; http://link.springer.com/content/pdf/10.1007/s11746-999-0197-x.pdf; http://link.springer.com/article/10.1007/s11746-999-0197-x/fulltext.html; http://link.springer.com/content/pdf/10.1007/s11746-999-0197-x

Abstract Lipase‐catalyzed acidolysis of acylglycerols of borage ( Borago officinalis L.) oil with a docosahexaenoic acid (DHA) concentrate, prepared from algal oil, in organic solvents was studied. Seven lipases were used as biocatalysts for the acidolysis reaction. Novozyme 435 from Candida antarctica , as compared to lipases from Mucor miehei and Pseudomonas sp., showed the highest degree of DHA incorporation into borage oil. Other lipases tested, such as those from Aspergillus niger, C. rugosa, Thermomyces lanuginousus and Achromobacter lunatus , were rather ineffective in the incorporation of DHA into borage oil. Effects of variation of reaction parameters, namely, enzyme load, temperature, time course, and type of solvent, were monitored for C. antarctica as the biocatalyst of choice. Incorporation of DHA increased with increasing amount of enzyme, reaching 27.4% at an enzyme concentration of 150 lipase activity units. As incubation time progressed, DHA incorporation also increased. After a reaction time of 24 h, the contents of total n‐6 and n‐3 polyunsaturated fatty acids in acylglycerols were 44.0 and 27.6%, respectively. The highest degree of DHA incorporation was achieved when hexane was used as the reaction medium. The positional distribution of DHA in modified borage oil was determined using pancreatic lipase hydrolysis. Results showed that DHA was randomly distributed over the sn ‐1, sn ‐2, and sn ‐3 positions of the triacylglycerol. Thus, preparation of modified borage oil acylglycerols containing both DHA (22:6n‐3; 27.4%) and γ‐linolenic acid (18:3n‐6; 17.0%) was successfully achieved and products so obtained may have beneficial effects beyond simple physical mixtures of the two oils. The final oil had a ratio of n‐3 to n‐6 of 0.42–0.62 which is nutritionally more suitable than the original unaltered borage oil.