Incorporation of capric acid in pumpkin seed oil by sn-1,3 regioselective lipase-catalyzed acidolysis

Abstract

-Structured lipids (SLs) are novel triacylglycerols obtained by changing the native fatty acid (FA) profiles or by the incorporation of a new desired FA in the acylglycerol backbone. These modified fats present important medical and functional properties for food applications. This work aimed to synthetize a MLM-type SL, which consists of triacylglycerols containing a medium-chain FA (M) at sn-1,3 positions and a long-chain FA (L) at sn-2 position, by acidolysis of pumpkin seed oil with capric acid, catalyzed by a commercial lipase preparation from Thermomyces lanuginosa (Lipozyme TL IM). Reactions were performed at 45°C, in solvent-free media, at 1:2 molar ratio (pumpkin seed oil:capric acid) and a fixed amount of immobilized lipase of 5%, 10%, 15% or 20%. Incorporations of C10:0 increased with time up to 31 h (29.9 ± 0.7 mol-%) when 5% lipase load was used. Significant differences were only observed between the results obtained with 5 and 20% of biocatalyst load. The subsequent experiment was carried out with 5% lipase load, at 45°C, 1:2 molar ratio and in the presence of n-hexane. The results showed slightly higher incorporation yields in the presence of solvent, namely at 48 h-reaction (34.7 ± 1.0 mol-%). However, since the structured lipids are to be used in food products, together with environmental and economic concerns, solvent-free systems are preferred. In this study, the synthesis of a MLM-type SL from pumpkin seed oil for food uses was well succeeded.Keywords: structured lipid / acidolysis / pumpkin seed oil / capric acid / lipozyme TL IM Résumé -Incorporation d'acide caprique dans de l'huile de pépin de citrouille par acidolyse catalysée par une lipase sn-1,3 régiosélective. Les lipides structurés sont de nouveaux triacylglycérols obtenus en changeant les profils des acides gras (AG) natifs ou par l'incorporation de nouveaux AG souhaités dans le squelette glycérol. Ces graisses modifiées présentent des propriétés médicales et fonctionnelles importantes pour des applications alimentaires. Ce travail vise à synthétiser un lipide structuré de type MLM, qui consiste en des triacylglycérols contenant un AG à chaîne moyenne (M) en positions sn-1,3 et un acide gras à chaîne longue (L) en position sn-2, par acidolyse de l'huile de graine de citrouille avec l'acide caprique, catalysée par une préparation commerciale de lipase de Thermomyces lanuginosa (Lipozyme TL IM). Les réactions ont été effectuées à 45°C, sans solvant, avec un rapport molaire de 1:2 (huile de graines de citrouille: acide caprique) et une quantité fixe de lipase immobilisée de 5 %, 10 %, 15 % ou 20 %. Avec une charge en lipase de 5 %, l'incorporation du C10:0 a augmenté avec le temps jusqu'à 31 h (29,9 ± 0,7 mol %). Des différences significatives ont été observées seulement entre les résultats obtenus avec 5 et 20 % de charge en biocatalyseur. L'expérience suivante a été réalisée avec une charge en lipase de 5 %, à 45°C, un rapport molaire 1:2 et en présence de n-hexane. Les résultats ont montré des rendements d'incorporation lég...

Argan Oil as a Rich Source of Linoleic Fatty Acid for Dietetic Structured Lipids Production

“…After 24 h, C10:0 molar incorporation was averaged in 21.2 mol.% and 22.0 mol.% after 48 h acidolysis. Similar results of capric acid incorporation by acidolysis in solvent-free systems, were previously reported, with virgin olive oil (27.1 ± 2.3 mol.%) and Lipozyme RM IM after 24 h [23], with Cucurbita maxima pumpkin seed oil (29.9 ± 0.7 mol.%) and Lipozyme TL IM, at 45 °C, after 31 h acidolysis [42].…”

Future of Structured Lipids: Enzymatic Synthesis and Their New Applications in Food Systems

“…to produce MLCT. Acidolysis, the reaction between triacylglycerol and free fatty acids, is the most widely used method for producing MLCT [ 37 , 38 ]. Usually, capric acid, caprylic acid, and lauric acid are utilized as the source of MCFAs, whereas corn oil, mango kernel fat, avocado oil, soybean oil, Echium seed oil, canola oil, corn oil, olive oil, and microbial oil are used to provide LCFAs.…”

Relation between the effect of increasing reaction time, reaction temperature and ratio of substrate on incorporation of lauric acid into palm kernel oil

“…MCT is not available naturally so it needs to be synthesized [6,7]. MCT synthesis is enzymatically more advantageous than chemically such as environmentally friendly reaction conditions, proceeding at lower temperatures, little or no reaction by-products, ease of product recovery and in controlling the reaction [8,9].…”

“…Incorporation of medium chain fatty acids (capric acid) into pumpkin seed oil by solvent-free enzymatic acidolysis system was carried out under the best reaction conditions, namely at 45 ℃ , 1:2 substrate ratio (molar basis), and 5% enzyme weight [9][10][11]. The results of previous studies revealed the success of incorporated lauric acid into Echium seed oil by enzymatic acidolysis of immobilized commercial lipase [12][13][14].…”