Construction On Spirulina Delivery System Loaded With Probiotics And Development Of Product

Probiotics are a class of active microorganisms that have beneficial effects on the body at appropriate doses.They have diverse physiological activities such as promoting nutrient digestion and absorption,anti-cancer,and enhancing immunity.However,in practical applications,probiotics are sensitive to processing,transportation,storage,and the gastrointestinal environment after ingestion,thereby losing activity and failing to achieve probiotic effects.Therefore,it is urgent to design carriers to protect probiotics.As a biological carrier,spirulina can achieve efficient loading of bioactive substances.Therefore,this topic uses spirulina as a carrier to construct a spirulina carrier system loaded with probiotics,and explores the structure,properties of the spirulina carrier system and its protective effect on probiotics.On this basis,a functional probiotic preparation product was developed and the product properties were studied.The research contents and conclusions are as follows :(1)The protective effect of spirulina carrier on probiotics was investigated by investigating the distribution of probiotics,the stability of probiotics and the digestion of gastrointestinal tract.The results showed that the structure of most spirulina remained intact after centrifugation and freeze-drying.Laser confocal images showed that some probiotics were distributed in spirulina.In addition,the spirulina carrier can effectively improve the viability of probiotics in a low pH environment(pH 1.5-4)and during low temperature storage.After storage at 4 °C for 28 days,the probiotic activity reduced by only 1.28 log CFU/mL.In vitro digestion showed that spirulina carrier could improve the gastrointestinal digestion activity of probiotics,and the activity of probiotics only reduced by 1.61 log CFU/mL after digestion.(2)In order to further improve the digestive stability of probiotics,the surface of spirulina was modified by chitosan to explore the effect of chitosan-modified spirulina carrier on the storage activity,gastrointestinal digestive activity and release of probiotics.The results showed that positively charged chitosan could be successfully attached to the surface of negatively charged spirulina by electrostatic interaction.Under the storage environment of 4 °C,the chitosan-modified spirulina carrier can improve the storage stability of probiotics due to its strong hydrophobic properties.In addition,the chitosan-modified spirulina carrier has more excellent gastrointestinal digestion protection ability,and the probiotic activity in the 0.5 % chitosan-modified spirulina carrier can be maintained at 8.98 ± 0.03 log CFU/mL after in vitro digestion.In addition,the chitosan-modified spirulina carrier also has good sustained release characteristics,which can be continuously released for up to 8 h in simulated intestinal fluid.(3)In order to further improve the storage stability of probiotics,spirulinaprobiotic powder products that can be stored at room temperature were prepared by vacuum freeze-drying.Owing to the low moisture characteristics of the sample before freeze-drying and the presence of spirulina,the freeze-dried protective agents had no significant effect on the viability of probiotics after vacuum freeze-drying.The dispersion experiment showed that the unmodified spirulina-probiotic powder had good dispersion,while the spirulina-probiotic powder modified by chitosan had poor dispersion.In addition,in vitro digestion showed that chitosan-modified spirulinaprobiotic powder could effectively improve the activity of probiotic powder in simulated gastrointestinal digestion,and the activity enhanced with the increase of chitosan concentration.The storage experiment showed that the probiotic activity of the chitosan-modified spirulina-probiotic powder was higher than 8.00 log CFU/g after28 days of storage at 25 °C.Compared with the 25 °C storage condition,the spirulinaprobiotic powder had better storage stability at 4 °C,and the probiotic activity remained basically unchanged after 28 days of storage.This study can provide new ideas for the construction of new carriers of probiotics,gastrointestinal protection and storage stability of probiotics,and provide reference for the preparation of new probiotic products.