Wheat Germ Oil for Enhanced Stability of Microencapsulated Fish Oil During Spray Drying and Optimization of Coating Component Ratios

Wheat germ oil (WGO) was added to improve resistance to oxidation and thermal deterioration in the spray drying of fish oils (FO), and appropriate coating material combinations were investigated in microencapsulation. FO and WGO blends were encapsulated using different ratios of maltodextrin (MD) and gum arabic (GA), with a fixed amount of whey protein isolate (WPI). The PV and TBARs' values of fish oil microcapsules with WGO were significantly lower than those of the control groups without WGO. After emulsification and spray drying, EPA and DHA levels were significantly lower in groups without WGO, whereas the highest EPA and DHA content was observed in the group coated with 10% WGO and a 1WPI:2MD mixture. Microencapsulation efficiency (ME) ranged from 71.20 to 78.55%, with the highest ME in the MD-coated groups instead of GA. Although no large cracks or pores were observed in any microcapsule groups, the most uniform round and granular particles were seen in the combination of 10% WGO and 1WPI:2MD coating. Thermogravimetric analysis demonstrated improved thermal stability of the core material, with shifts in peak positions suggesting interactions between wall and core materials. Increasing WGO raised thermal decomposition temperatures, enhancing stability. In conclusion, MD was found to be more suitable than GA for fish oil microencapsulation with WPI due to its higher microencapsulation efficiency, more favorable particle morphology, and greater oxidative and thermal stability.