DHA emulsion-assisted gel encapsulation enhances probiotic stress resistance

Innovatively proposed the idea of using long-chain fatty acids beneficial to the human body, such as docosahexaenoic acid (DHA), to fill the three-dimensional network structure of hydrogels. • DHA oil-in-water emulsions can enhance the viability of probiotics under simulated industrial processing conditions. • DHA oil-in-water emulsions can effectively fill the pores in the hydrogel network. • Modified hydrogels prepared using DHA emulsions demonstrate significantly superior encapsulation performance for embedded probiotics compared to unmodified traditional hydrogels. • Modified hydrogels provide significantly better protection for embedded probiotics in simulated gastric and intestinal fluids than traditional hydrogels. Although gel encapsulation is widely used in the delivery of probiotics, its three-dimensional porous structure has inherent drawbacks, probiotics may leak out through the pores, and gastrointestinal stress factors may also penetrate into the gel through the pores. In this study, we prepared a docosahexaenoic acid (DHA) oil-in-water emulsion (DHA-ME) and evaluated its effects on probiotics, showing that the 0.0075% (w/v) DHA-ME improved the survival rate of probiotics against the heat and freeze-drying stress. We then incorporated this into a gelatin-gellan gum gel to prepare a modified gel (GDG). Taking Bifidobacterium longum subsp. longum BL21 as an example, the addition of DHA-ME yielded a retention rate of nearly 100% in simulated intestinal fluid after 24 h. Moreover, following incubation in simulated intestinal and gastric fluids, BL21 activity increased by 25.3% and 657.5%, respectively. This strategy offers a new approach to the delivery of probiotics via gels.