Preparation and Physicochemical Characterization of Docosahexaenoic Acid Microcapsules with High Algal Oil Loading

HU Ronghai; CHEN Wenrong; CUI Shaohua; FANG Suqiong; WAN Zhili

doi:10.13982/j.mfst.1673-9078.2026.1.1481

Abstract：To improve the oxidative stability and organoleptic flavor of docosahexaenoic acid(DHA),and enhance its application value in nutritional and health products,DHA algal oil was encapsulated in whey protein isolate(WPI)and pectin(PEC),gum arabic(GA),and octenyl succinic anhydride-modified starch(OSA)matrix using a complex coacervation method.The effects of different complexes on the physicochemical properties of emulsions,total oil and surface oil contents,storage stability,and apparent morphology of microcapsules with corresponding formulations were systematically examined.The results showed that the WPI-PEC complex significantly enhanced the emulsion stability of DHA algal oil,with an average particle size of 362 nm,D[3,2]of 312 nm,and D[4,3]of 391 nm.In addition,the LUMiSizer transmittance fingerprint curves exhibited only minor fluctuations in the transmittance.Furthermore,the spray-dried WPI-PEC microcapsules exhibited an oil loading capacity of approximately 50%,a low surface oil content of 2.59%,and a complete microstructure,as revealed by scanning electron microscopy.After storage at 40℃for 3 months,the peroxide value remained lower than 1 g/100 g,and the samples exhibited a high sensory score with a low fishy flavor.However,the addition of GA and OSA weakened the emulsification properties of WPI,resulting in emulsions with large particle sizes and lower stability,high surface oil content,incomplete microstructures,and poor storage stability of the microcapsule powder.In conclusion,the WPI-PEC complexes exhibited a synergistic effect that improved the stability and quality of DHA algal oil emulsions and microcapsules,thus laying a foundation for enhancing the application value of DHA algal oil.