Stability of perilla seed oil based PUFA-rich structured lipids using enzymatic interesterification: A thermo-oxidative kinetic study

Abstract

Enzymatic interesterification (EIE) serves as a viable approach for enhancing the stability and functional characteristics of fats and oils rich in polyunsaturated fatty acid (PUFA) such as perilla seed oil (PSO). This investigation conducted a comprehensive analysis of the oxidative stability and kinetics behaviour of PUFA-rich enzymatically interesterified structured lipids (SL) developed using PSO. Further, these SL were enriched with varying concentration of rosemary extract (RE) and their stability was assessed using rancimat method under accelerated temperature (90–120 °C). Initial assessment of oxidative indices revealed that the obtained SL exhibited lower primary (peroxide and conjugated diene) and secondary indices (p-anisidine and conjugated trienes) compared to PSO. Furthermore, fatty acid composition analysis revealed that incorporation of PSO into palmolein during interesterification resulted in reduction of PUFA content in the obtained SL, thus achieving a balanced saturated: monounsaturated: polyunsaturated ratio of fatty acid (1.2:1.2:1) in SL. The analysis of kinetic parameters demonstrated that SL displayed lower activation energies (Ea,106.17 kJ/mol), frequency factor (A, 22.38 ×1013), activation enthalpies (∆H++,103.03 kJ/mol) and entropies (∆S++, 19.52 J/mol K) as well as more negative temperature coefficient (Tc, −8.96) compared to PSO. RE incorporation at the level of 1500 ppm in SL have higher antioxidant efficacy with estimated shelf of 188 days (IP25) and comparable with BHT at 200 ppm. These results are validated using the principal component analysis and correlation analysis. The findings of the present study hold significant implications for the fat and oil industry, as the utilization of such SL can extend shelf-life while preserving the nutritional value of PUFA-rich oils.