Fabrication Of Water-in-oil Emulsion Encapsulated With Probiotics And The Development Of Related Products

Probiotics are a group of active microorganisms that have beneficial effects on human body when ingested in proper amount.They usually exist in the human gut and interact with the body to affect human health.Probiotics can reshape the intestinal microecological environment of the human body with achieving anti-cancer,improving immunity,treating obesity and other effects.However,most probiotics have high requirements on the living environment because they are easy to be inactivated during processing,storage and digestion,leading to their inability to perform their physiological functions normally.At present,there are many delivery technologies for the transportation and protection of probiotics,such as hydrogel,microcapsule,etc.,but there are few studies on water-in-oil emulsion system.The research on the load of probiotics in water-in-oil emulsion system is beneficial to expand the application range of probiotics in oil-based or low-energy food industry and has great significance for the development of probiotics products.In this study,Bifidobacterium was selected as the model bacteria,and the water-in-oil emulsion system was used as the carrier to transport and protect it.The physical structure and probiotic activity of samples in different environments were investigated,then apply in frozen food and develop a probiotic fortified margarine.The main research contents are as follows:(1)Research on W/O HIPEs loading probiotics and gastrointestinal protectionUsing polyglycerin polycastinoleate(PGPR)as oil-soluble surfactants,beeswax and corn oil as oil phases,and two groups of different water phases(normal saline and skim milk),water-in-oil(W/O)high-internal phase emulsions(HIPEs)were prepared for encapsulation and protection of probiotics.The effects of skim milk on the physical structure of the emulsion system and the activity of probiotics were investigated,and the activity of probiotics in different environments,such as storage,low acid and in vitro digestion,were measured.The results showed that the added skim milk group had higher apparent viscosity and preference for solids,while the saline group did the opposite.The samples have good p H stability and centrifugal stability.Besides,the addition of skim milk gives the sample storage stability.And both groups of samples showed excellent protective effects on probiotics under simulated digestion conditions in vitro.These results proved that the W/O HIPEs is beneficial to probiotics loading and has good gastrointestinal protection ability.(2)Fabrication of anti-freeze W/O emulsion and physicochemical properties effects on probioticsAn antifreeze oil-in-water emulsion was prepared by adjusting the composition of the water phase to form a network structure,and trehalose was added as a cryoprotectant to transport and protect probiotics.The effects of different concentrations of glycerol,CMC and trehalose on the rheological properties/p H stability and centrifugal stability of the emulsion were investigated,and the optimal concentration was obtained for probiotics loading.The freeze-thaw stability,low temperature storage stability and in vitro simulated digestion analysis of the emulsion loaded with probiotics were also investigated.The optimized results show that 70% glycerol and 1% CMC are the most suitable parameters for emulsion preparation.The results showed that glycerol and trehalose had a little effect on the rheological properties of the emulsion,and the prepared samples had good p H stability and centrifugal stability.The addition of glycerin and trehalose gives the emulsion ability to protect probiotics during low temperature storage and freezing.The results of simulated digestion in vitro showed that the W/O emulsion could protect the probiotics in the stomach and release slowly in the small intestine,ensuring the physiological function of probiotics.(3)Application and products development of the probiotics thaw stable system in frozen food.Based on the experimental results of W/O emulsion on probiotics,the freezingthawing stable emulsion was applied to frozen food by adjusting the content of solid fat and glycerin.And a probiotic fortified margarine product was developed.The effect of margarine process on probiotics activity was investigated,and all samples were detected by texture,creaming ability,rheological properties and storage stability analysis.The results showed that the preparation of margarine caused slight damage to the activity of probiotics,but samples had good hardness,viscosity and creaming ratio.The rheological properties of samples were affected by the content of solid fat.The samples with high solid fat content had apparent viscosity,and tended to be solid,while the samples with low solid fat content had the opposite effect.The results of storage stability experiment showed that the glycerin addition was beneficial to maintain the stability of probiotics during storage.