title: Glycidyl esters in refined palm (Elaeis guineensis) oil and related fractions. Part II: practical recommendations for effective mitigation.
abstract: In a previous work, it was shown that at high temperatures (up to 280°C) glycidyl esters (GE) are formed from diacylglycerols (DAG) via elimination of free fatty acid (FFA). In the present study, the impact of DAG content and temperature on the formation of GE using a model vacuum system mimicking industrial edible oil deodorization is investigated. These deodorization experiments confirmed that the formation of GE from DAG is extensive at temperatures above 230-240°C, and therefore, this value should be considered as an upper limit for refining operations. Furthermore, experimental data suggest that the formation of GE accelerates in particular when the DAG levels in refined oils exceed 3-4% of total lipids. Analysis of the lipid composition of crude palm oil (CPO) samples allowed the estimation that this critical DAG content corresponds to about 1.9-2.5% of FFA, which is the conventional quality marker of CPO. Moreover, high levels (>100ppm) of GE were also found in palm fatty acid distillate samples, which may indicate that the level of GE in fully refined palm oils also depends on the elimination rate of GE into the fatty acid distillate.
authors.affiliation: Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Craft
authors.affiliation: Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland.
authors.forename: Kornél
authors.initials: K
authors.lastname: Nagy
authors.affiliation: Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland.
authors.forename: Walburga
authors.initials: W
authors.lastname: Seefelder
authors.affiliation: Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland.
authors.forename: Mathieu
authors.initials: M
authors.lastname: Dubois
authors.affiliation: Nestlé Research Center, Vers-chez-les-Blanc, Lausanne, Switzerland. Electronic address: frederic.destaillats@rdls.nestle.com.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Destaillats
mesh_terms: D004075:Diglycerides / Q000737:chemistry*; D004952:Esters / Q000737:chemistry*; D005230:Fatty Acids, Nonesterified / Q000032:analysis / Q000737:chemistry*; D000073878:Palm Oil; D010938:Plant Oils / Q000737:chemistry*
chemical_list: D004075:Diglycerides; D004952:Esters; D005230:Fatty Acids, Nonesterified; D010938:Plant Oils; D000073878:Palm Oil
keywords: Deodorization; Diacylglycerol; Free fatty acid; Glycidyl esters; Oil palm (Elaeis guineensis); Oil refining; Palm oil