Puerarin-Hericium Insoluble Dietary Fiber Compound Preparation of Microcapsule and Study of the Physical and Chemical Properties

Objective: To prepare puerarin-Hericium insoluble dietary fiber composite microcapsules, and promote the research and development of puerarin related products by improving its embedding rate, antioxidant properties and bioaccessibility. Methods: Puerarin microcapsules were prepared with 2.0% carrageenan, 3.0% sodium alginate, 0.5 g insoluble dietary fiber, 10.0 mg puerarin, and 5.0% CaCl₂ solution (with no insoluble dietary fiber added as the control group). The embedding rate, antioxidant properties, simulated digestion and release rate in vivo, and bioaccessibility were calculated. The microstructure was observed by scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). Results: Hericium insoluble dietary fiber could be used as puerarin microcapsule wall material, and the embedding rate was higher than 75.8%, the highest could amount to 94.66%, the bearing capacity of puerarin by blank group increased to 0.60% of the top add dietary fiber was 1.37%. Before and after digestion, the scavenging ability of DPPH and ABTS⁺ were significantly lower than those of puerarin microcapsules without soluble dietary fiber, which could achieve the effect of delaying antioxidant properties. The study of in vivo digestion showed that puerarin embedded in hericium insoluble dietary fiber (minimum 9.46%) could be released slowly in the stomach compared with free puerarin (17.46%). After entering the intestine, puerarin was released rapidly and dissolved in a large amount in the simulated intestinal fluid. The release rate of puerarin in the intestine increased from 22.93% of free puerarin to up to 92.59% of hericium insoluble dietary fiber, achieving accurate intestinal release and significantly improving the bioaccessibility of puerarin, which was 2.9~3.9 times that of free puerarin. SEM, FT-IR and XRD confirm that the hericium insoluble dietary fiber obtained by ultrasonic-assisted extraction could be used as the wall material of puerarin microcapsules, which could improve the shortcomings of exposing puerarin in the control group microcapsules and make the microcapsules more compact in texture. It was also confirmed that the hericium insoluble dietary fiber made the crystallinity of puerarin decrease or disappear and the characteristic diffraction peak of puerarin shift or weaken, which achieved a good embedding effect. Conclusion: Adding hericium insoluble dietary fiber could enhance the dissolution rate of puerarin, delay the antioxidant time of puerarin combined with sibelium, achieve the fixed-point release in the intestine, raise the biological availability and biological utilization ratio of puerarin, which can be used as puerarin microcapsule wall material.