Bio‐ and auto‐catalytic esterification of high acid mowrah fat and palm kernel oil

Abstract

An alternative process for the deacidification of high acid palm kernel oil (PKO) and mowrah fat, MF, was investigated by autocatalytic and enzyme (Mucor miehei)-catalyzed esterification of free fatty acids (FFA). In the process monoglyceride (MG) or glycerol was used as esterifying agent. The results of the autocatalytic esterification process were compared with that of bioesterification with respect to reduction of FFA. For the former process the optimum reaction temperature and oil to MG or glycerol proportion were established. The optimum reaction temperature for PKO free fatty acids with stoichiometric quantity of glycerol is 160-165 °C (at 10 mm Hg pressure (1.33 kPa)) and after 6 h the FFA content is reduced to 1.6%, w/w, (from 25.0%, w/w, original). However, if a stoichiometric amount of MG is used as an esterifying agent the optimum esterification temperature is found to be 195-200 °C (at 10 mm Hg pressure (1.33 kPa)), and after 8 h the FFA content is reduced to 3.4%, w/w. On the contrary, biorefining of PKO at 60 °C temperature and 10 mm Hg pressure (1.33 kPa) using optimum (40% excess) quantity of glycerol or 50% excess MG reduces the FFA level to 1.2% and 0.7%, w/w, respectively. Similar study on bio- and auto-catalytic esterification of MF was also carried out and got comparable results. The final products were then characterized. La matiere grasse de Madhuca latifolia, le beurre de mowra, et l'huile palmiste sont utilisees pour la production de succedanes de beurre de cacao. Un procede alternatif pour la desacidification de ces produits est recherche par esterification des acides gras libres, catalysee par une enzyme ou autocatalytique. Dans le procede, un monoglyceride ou du glycerol est utilise comme agent esterifiant. Les resultats de l'esterification autocatalytique sont compares avec ceux de la bioesterification en evaluant la reduction des teneurs en acides gras libres.