Browsing by Author "Kalo, Paavo J."
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- Composition and contents of classes of neutral lipids in non-starch and starch lipid extracts of flour, sourdough and broa (Portuguese sourdough bread)Publication . Rocha, João M.; Kalo, Paavo J.; Malcata, F. Xavier
- Lipase-catalyzed acidolysis of butterfat with oleic acid: characterization of process and productPublication . Balcão, Victor M.; Kemppinen, Asmo; Malcata, F. Xavier; Kalo, Paavo J.The modification of anhydrous butterfat via interesterification reactions with oleic acid catalyzed by a lipase from Mucor circinelloides immobilized by adsorption onto hydrophobic hollow fibers is described. A reasonable degree of incorporation of free (externally added) oleic acid into the triacylglycerols of butterfat has been achieved while short-chain fatty acid residues remained virtually unaffected. Total saturated triacylglycerols decreased by 27%, and triacylglycerols with 32–44 acyl carbons (which contained two or three lauric, myristic, or palmitic acid residues) decreased by 33%. Total monoene and polyene triacylglycerols increased by 21% and 17%, respectively. The triacylglycerols (TAG) of interesterified butterfat had approximately 27% more oleic acid residues and approximately 8% less lauric, 6% less myristic, and 6% less palmitic acid residues than those of the original butterfat; the fraction of low-melting TAG peak increased by 19% whereas that of high-melting TAG decreased by 83%. Although a certain degree of butterfat hydrolysis was observed, enzymatic acidolysis was technically feasible and able to produce a modified butterfat with a stronger nutraceutical character.
- Modification of butterfat by selective hydrolysis and interesterification by lipase: Process and product characterizationPublication . Balcão, Victor M.; Kemppinen, Asmo; Malcata, F. Xavier; Kalo, Paavo J.Butterfat was chemically modified via combined hydrolysis and interesterification, catalyzed by a commercial lipase immobilized onto a bundle of hydrophobic hollow fibers. The main goal of this research effort was to engineer butterfat with improved nutritional properties by taking advantage of the sn-1,3 specificity and fatty acid specificity of a lipase in hydrolysis and ester interchange reactions, and concomitantly decrease its level of long-chain saturated fatty acid residues (viz., lauric, myristic, and palmitic acids) and change its melting properties. All reactions were carried out at 40°C in a solvent free system under controlled water activity, and their extent was monitored via chromatographic assays for free fatty acids, esterified fatty acid moieties, and triacylglycerols; the thermal behavior of the modified butterfat was also assessed via calorimetry. Lipase-modified butterfat possesses a wider melting temperature range than regular butterfat. The total saturated triacylglycerols decreased by 2.2%, whereas triacylglycerols with 28–46 acyl carbons (which contained two or three lauric, myristic, or palmitic acid moieties) decreased by 13%. The total monoene triacylglycerols increased by 5.4%, whereas polyene triacylglycerols decreased by 2.9%. The triacylglycerols of interesterified butterfat had ca. 10.9% less lauric, 10.7% less myristic, and 13.6% less palmitic acid residues than those of the original butterfat.
- Separation and identification of neutral cereal lipids by normal phasePublication . Rocha, João M.; Kalo, Paavo J.; Ollilainen, Velimatti; Malcata, F. XavierA novel method was developed for the analysis of molecular species in neutral lipid classes, using separation by normal phase high-performance liquid chromatography, followed by detection by evaporative light-scattering and electrospray ionization tandem mass spectrometry. Monoacid standards, i.e. sterol esters, triacylglycerols, fatty acids, diacylglycerols, free sterols and monoacylglycerols, were separated to baseline on microbore 3 m-silica gel columns. Complete or partial separation of molecular species in each lipid class permitted identification by automatic tandem mass spectrometry of ammonium adducts, produced via positive electrospray ionization. After optimization of the method, separation and identification of molecular species of various lipid classes was comprehensively tested by analysis of neutral lipids from the free lipid extract of maize flour.
- Separation of neutral lipid classes by high-performance liquid chromatography using light-scattering detection: analysis of vegetable oils and maize flourPublication . Rocha, João M.; Kalo, Paavo J.; Ollilainen, Velimatti; Malcata, F. Xavier