Enzymatic synthesis of medium‐chain triacylglycerols by alcoholysis and interesterification of copra oil using a crude papain lipase preparation

Abstract

We have examined the possibility of producing analogs of medium-chain triglycerides (MCT) from copra oil, i.e. a triacylglycerol mixture with a high content of medium-chain fatty acid moieties (C 6 -C 10 ). A two-step enzymatic process was used in which copra triacylglycerols were first split with papain lipase by alcoholysis with an alkyl alcohol and then subjected to interesterification with the alkyl esters recovered using papain lipase. Effects of temperature, water activity/content, substrate ratio, biocatalyst amount, and alcohol chain length were also investigated. On the one hand, the sn-3 stereoselectivity of the lipase in the alcoholysis of copra oil with butanol has permitted a direct enrichment of caproic, caprylic and capric moieties in the synthesized butyl esters. Thus, in the batch reactor, the reaction led to about 31% conversion of the oil after 24 h, and the content of C 6 -C 10 acids in the synthesized esters increased from about 16% in the starting oil to almost 42%. A similar enzymatic alcoholysis in a packed-bed column bioreactor gave 31% conversion of the oil after 120 min of reactor residence time. The reaction was also very selective because the C 6 -C 10 fatty acyl groups represented about half of the newly formed butyl esters, whereas they accounted for only 16% of total fatty acids in the starting oil. On the other hand, the transesterification of the alkyl esters recovered (highly enriched in C 6 -C 10 fatty acyl groups) with native copra oil directly led to an increase in the content of MCT in the oil, from 18 mol-% at the beginning of the reaction to 61 mol-% of MCT after a time period of 72 h in the batch reactor.

Medium chain triglycerides (MCT): State‐of‐the‐art on chemistry, synthesis, health benefits and applications in food industry

“…Researchers have explored lipases from several sources for this purpose and their usage requires extensive prior optimization protocols. Caro et al (2004) used copra oil as the substrate and crude papain lipase as the enzyme for a two-step synthesis of MCT oil. First, the alcoholysis of copra oil triglycerides with butanol was initiated.…”

“…Caro et al. (2004) used copra oil as the substrate and crude papain lipase as the enzyme for a two‐step synthesis of MCT oil. First, the alcoholysis of copra oil triglycerides with butanol was initiated.…”

Plant latex lipase as biocatalysts for biodiesel production

“…Studies carried out on C. papaya showed that its crude latex has a very strong activity on shortchain triacylglycerol (TAG) and sn3 stereoselectivity in hydrolysis reactions of chiral TAG substrates (Villeneuve et al, 1995). These observations led to industrial use of this latex in particular applications, such as the synthesis of low-calorie triacylglycerols (Foglia and Villeneuve, 1997a) or medium-chain TAG (Caro et al, 2004). These results have prompted interest in other latex plant extracts, in particular, the unripe fruit of the babaco plant (Vasconcellea X Heilbornii cv., ex Carica pentagona Heilbornii) (Kyndt et al, 2005), a member of the papaya family native to the subtropical mountains of Ecuador, which contains a latex similar to the one in C. papaya.…”

“…It is worth noting that only a few microbial lipases, such as that of Thermomyces lanuginosus (Humicola lanuginosa) (Boel and Huge-Jensen, 1998) have shown similar levels of resistance so far in a large pH range up to pH 10. Concerning lipase activity, the majority of reactions are often carried out in nearly neutral to alkaline pH (Tecelão et al, 2012;Caro et al, 2004;Lee and Foglia, 2000). For example, the CPL mediated hydrolysis in olive oil found its optimum at pH levels between 9 and 9.5 (Abdelkafi et al, 2011), while the SA in the hydrolysis of TAGs present in human diet was better at pH 6 .…”

Neutral Lipid Characterization of Non‐Water‐Soluble Fractions of Carica Papaya Latex

“…Recently, the presence of hydrolytic enzymes such as GDSL-motif carboxylester hydrolase [6] or lipase has been demonstrated [7]. For the latter, an important characterization of its biocatalytic activities has been carried out [8][9][10][11], and some potential applications were also described in the field of racemic mixture resolution [12][13][14], oil and fat restructuration [15][16][17], and enzyme replacement therapy [18]. Regarding other molecular species naturally present in the non-watersoluble fraction of CPL, very little information exists, particularly for lipids, for which little if any characterization can be found in the literature.…”