Selective Enrichment of Conjugated Linoleic Acid Isomers in Their Mixtures Using Combined Chemical and Enzymatic Methods

• Published in: Journal of the American Oil Chemists' Society 2017-04, Vol.94 (4), p.577-585
• Main Authors: Kim, Jiwon, Chung, Min-Yu, Choi, Hee-Don, Choi, In-Wook, Kim, In-Hwan, Chun, Hyang Sook, Kim, Byung Hee
• Format: Article
• Language: English
• Subjects: Agriculture; Biomaterials; Biotechnology; Candida rugosa lipase; Chemistry; Chemistry and Materials Science; cis‐9,trans‐11 Conjugated linoleic acid; Crystallization; Enzymes; Esterification; Fatty acids; Food Science; Fractionation; Hogs; Industrial Chemistry/Chemical Engineering; Isomers; Lipase; Moisture content; Original Paper; Reaction time; Recirculating packed‐bed reactor; Substrates; trans‐10,cis‐12 Conjugated linoleic acid; Urea; Urea crystallization; Ureas; Water content
• ISSN: 0003-021X; 1558-9331
• DOI: 10.1007/s11746-017-2970-6

The aim of this study was to selectively enrich t 10, c 12-conjugated linoleic acid ( t 10, c 12-CLA) and c 9, t 11-CLA in commercial CLA mixtures using a combination of urea crystallization and lipase-catalyzed esterification. The objective of the urea fractionation is to remove saturated and monounsaturated fatty acids (FA) from the CLA mixtures. CLA-enriched free FA (FFA) mixtures containing 53.8 wt% t 10, c 12-CLA and 39.1 wt% c 9, t 11-CLA were produced from the CLA mixtures containing ~34 wt% each of the two CLA isomers by a urea crystallization using methanol and the urea-to-FA weight ratio of 2.5:1. The CLA-enriched FFA mixtures were partially esterified with dodecan-1-ol in a recirculating packed-bed reactor using an immobilized lipase from Candida rugosa to further enrich the t 10, c 12-CLA and c 9, t 11-CLA in an FFA fraction and an FA dodecyl ester fraction, respectively, under the optimal conditions, i.e., temperature, 20 °C; FA-to-dodecan-1-ol molar ratio, 1:1; water content, 2 wt% of total substrates; residence time, 5 min; and reaction time, 24 h (for t 10, c 12-CLA enrichment) and 12 h (for c 9, t 11-CLA enrichment). After the reaction, an FFA fraction with 72.6 wt% t 10, c 12-CLA was obtained. Another FFA fraction with 62.0 wt% c 9, t 11-CLA was recovered after the saponification of the FA dodecyl ester fraction. The yields of t 10, c 12-CLA and c 9, t 11-CLA in the FFA fractions were 43.6 and 21.5 wt%, respectively, based on their initial weights in the CLA mixtures.