Structured lipids are lipids presenting novel functional and bioactive properties different from natural fats. Low-calorie triacylglycerols (TAG) are structured TAG containing a long-chain fatty acid (L) at the position sn-2 and medium-chain fatty acids (M), at the external positions of TAG. They are known as MLM and they are important to control obesity, since they present a caloric value of 5 kcal/g, and also for persons with malabsorption problems. MLM can be synthesized by lipase-catalyzed reactions, namely acidolysis of oils with medium-chain fatty acids or interesterification of oils with ethyl or methyl ester of medium-chain fatty acids. The use of (i) low-cost crude oils and (ii) immobilized lipases with high activity and stability are strategies to reduce process costs and make the process competitive. The aim of this study was to produce MLM by acidolysis of crude olive pomace oils with different acidities with caprylic (C8:0) or capric (C10:0) acids, catalyzed by the commercial immobilized 1,3-regioselective lipase from Rhizomucor miehei (Lipozyme RM IM, from Novozymes), in solvent-free media. Crude olive pomace oils containing additional oleic acid to give an acidity of 3.5, 10, 15 or 20 % of free fatty acids and a molar ratio oil/medium-chain fatty acid of 1:2 were tested. The acidolysis was carried out at 50°C under agitation for 48 hours. Samples were taken along the reaction time and the consumed C8:0 (C10:0) and TAG and the formation of new TAG were evaluated by GC-on column. Apparent equilibrium was attained after 7 h acidolysis. The yield of new TAG (MLM) showed to be independent from the initial acidity of the crude oil, which shows that the activity of this biocatalyst was not affected by the presence of free oleic acid up to 20 %. Also, Lipozyme RM IM did not show any preference towards caprylic or capric acids. At equilibrium, the yields of new TAG were c.a. 55 % for all the conditions tested. These results are very promising since they show the possibility of using high-acidic low-cost olive pomace oil, a by-product of the olive oil industry, to produce high value-added structured lipids.
The effect of the acidity of crude olive pomace oils in the production of low-calorie structured lipids catalyzed by the immobilized lipase from Rhizomucor miehei / G.C. Heinzl, V. Martinis, D.A. Mota, D. Faria, S. Ferreira-Dias. ((Intervento presentato al 4. convegno Meeting of the College of Chemistry : Chemistry : shaping the future tenutosi a Lisboa nel 2019.
The effect of the acidity of crude olive pomace oils in the production of low-calorie structured lipids catalyzed by the immobilized lipase from Rhizomucor miehei
G.C. Heinzl;
2019
Abstract
Structured lipids are lipids presenting novel functional and bioactive properties different from natural fats. Low-calorie triacylglycerols (TAG) are structured TAG containing a long-chain fatty acid (L) at the position sn-2 and medium-chain fatty acids (M), at the external positions of TAG. They are known as MLM and they are important to control obesity, since they present a caloric value of 5 kcal/g, and also for persons with malabsorption problems. MLM can be synthesized by lipase-catalyzed reactions, namely acidolysis of oils with medium-chain fatty acids or interesterification of oils with ethyl or methyl ester of medium-chain fatty acids. The use of (i) low-cost crude oils and (ii) immobilized lipases with high activity and stability are strategies to reduce process costs and make the process competitive. The aim of this study was to produce MLM by acidolysis of crude olive pomace oils with different acidities with caprylic (C8:0) or capric (C10:0) acids, catalyzed by the commercial immobilized 1,3-regioselective lipase from Rhizomucor miehei (Lipozyme RM IM, from Novozymes), in solvent-free media. Crude olive pomace oils containing additional oleic acid to give an acidity of 3.5, 10, 15 or 20 % of free fatty acids and a molar ratio oil/medium-chain fatty acid of 1:2 were tested. The acidolysis was carried out at 50°C under agitation for 48 hours. Samples were taken along the reaction time and the consumed C8:0 (C10:0) and TAG and the formation of new TAG were evaluated by GC-on column. Apparent equilibrium was attained after 7 h acidolysis. The yield of new TAG (MLM) showed to be independent from the initial acidity of the crude oil, which shows that the activity of this biocatalyst was not affected by the presence of free oleic acid up to 20 %. Also, Lipozyme RM IM did not show any preference towards caprylic or capric acids. At equilibrium, the yields of new TAG were c.a. 55 % for all the conditions tested. These results are very promising since they show the possibility of using high-acidic low-cost olive pomace oil, a by-product of the olive oil industry, to produce high value-added structured lipids.
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