Quality Evaluation of Plant Oil Blends Interesterified by Using Immobilized Rhizomucor miehei Lipase

The aim of this research was to evaluate the quality and oxidative stability of enzymatically interesterified plant oil blends. The model plant oil blends consisted of tomato seed oil and coconut oil, which were applied to enzymatic interesterification in the presence of a microbial lipase. To obtain quality characteristics of the enzymatically interesterified oil blends, the following analyses were performed: fatty acids composition and their distribution in internal position (sn-2) in triacylglycerols, oxidative induction time, melting profile, acid value (AV), and peroxide value (PV). The analyzed oil blends contain 6 to 25% monounsaturated fatty acids and 16 to 42% polyunsaturated fatty acids. Additionally, it was noticed that the major monounsaturated fatty acid was oleic acid, with its contribution ranging from 9 to 19%. In most cases, oleic and linoleic acids occupied the sn-2 position of the triacylglycerol molecules, with their contribution reaching 35 to 72% and 34 to 71%, respectively. The enzymatically interesterified oil mixtures were characterized by a relatively long oxidation induction time (41-87 min). Melting profiles of the tested samples revealed the presence of a diversified number of endothermic peaks. The AV and PV of the tested oil blends exceeded 10 mg KOH g(-1) fat and 1 meq O-2 kg(-1) fat, respectively. In conclusion, the tested interesterified plant oil blends are characterized by acceptable thermal and oxidative stability and fatty acid profile.