Design-Driven Production of Soybean Oil-Based Structured Fats as Potential Substitutes for Palm-Based Fats

Abstract

This study examined whether enzymatic modification of soybean oil (SBO) can be tailored to produce trans-free fats with physicochemical properties comparable to palm olein, stearin, or palm-mid fractions (PMFs). US-grown SBO was modified by lipase-catalyzed acidolysis using palmitic acid at linearly interpolated substrate molar ratios (C16:0: SBO of 0.6, 2.1, and 6.8) that produced palmitic acid–enriched tailored fats with targeted total saturated fatty acid (TSFA) of approximately 30%, 50%, and 70%. The products were predominantly triacylglycerols (94.44%–95.18%) and showed key TAG species found in palm olein and stearin, including POP/POO (30.51%–33.51%) and POSt (11.40%–42.01%). Thermal analysis showed a shift from SBO's low-temperature melting profile (−41.7°C to −5.5°C) to higher-temperature melting profile in the products (−38.2°C to 54.0°C) compared to PMFs (4.6°C–37.7°C). Solid fat content at 30°C increased from 0% (SBO) to 25.2%–41.5% (products). Under accelerated storage at 50°C for 35 days, the 65% TSFA product showed the slowest rise in total oxidation value (9.13–32.80). This study demonstrated a technology-oriented, systematic framework for producing palm olein-like, palm oil-like, and palm stearin-like structured fats from a single non-tropical feedstock. By integrating interpolation-based compositional targeting, validation, scale-up, and post-reaction purification, the study established a practical route for tailoring soybean oil across distinct functional fat classes relevant to food applications. The results also identified the main practicability trade-offs of the approach, particularly the balance between improved functionality at higher C16:0 incorporation and the increased purification burden to remove unreacted C16:0 and yield loss associated with such products.