Enhancing stability of 1,3-dioleic acid-2-palmitate (OPO) through microencapsulation: A comparative study of single- and double-layer microcapsules

1,3-dioleic acid-2-palmitate (OPO), a widely used breast milk substitution fat, is susceptible to oxidation and the formation of harmful substances during preparation and processing. To overcome these challenges, single- and double-layer microcapsules were developed using microencapsulation technology and compared in terms of their functionality. Through optimized preparation conditions, the encapsulation efficiency reached 86.24% for single-layer microcapsules and 85.94% for double-layer microcapsules. Analysis using FTIR, XRD, and SEM confirmed the formation of well-enclosed structures in both types of microcapsules. DSC results demonstrated significantly higher enthalpy values (21.97 J/g and 50.80 J/g) for the microcapsules, surpassing unencapsulated OPO (0.88 J/g) (P < 0.05), highlighting the enhanced thermal stability achieved through microencapsulation. Storage experiments revealed that the average particle size of single-layer microcapsules increased from 2.1 μm to 10.3 μm, while the double-layer microcapsules maintained a particle size range of 3.0–4.0 μm. Following storage, the enthalpy values decreased by 70.30% for single-layer microcapsules and 56.54% for double-layer microcapsules. Additionally, TBA values rose from 7.67 mgMDA/kg oil to 15.22 mgMDA/kg oil for single-layer microcapsules, while the double-layer microcapsules consistently remained around 3.60 mgMDA/kg oil. Analysis of total fatty acids during storage revealed a decline of 16.47% in unsaturated fatty acids for single-layer microcapsules, compared to only a 1.00% decrease for double-layer microcapsules, highlighting the superior antioxidant activity of the double-layer structure. Ultimately, these findings demonstrate that double-layer microencapsulation technology enhances the stability of OPO, expanding its potential applications.