Biochemical and physical investigations on detoxification of ginkgo kernel juice using probiotic fermentation with macroporous resin addition

The toxicity of ginkgo kernel is a global concern,restricting its consumption as a medicinal food.This study focuses on eliminating the toxic components,specifically ginkgolic acid,from ginkgo kernel juice.The approach used was probiotic fermentation with autochthonous lactic acid bacteria combined with macroporous resin.Compared to using lactic acid fermentation alone,adding macroporous resin during probiotic fermentation significantly enhanced the removal of toxic ginkgolic acid and 4'-O-methylpyridoxine from ginkgo kernel juice.After 48 h of fermentation with macroporous resin,the contents of ginkgolic acid and 4'-O-methylpyridoxine decreased by more than 69%and 61%,respectively.Interestingly,the adsorption of microbial growth inhibitors,such as ginkgolic acid,4'-O-methylpyridoxine,and phenolics,by the resin did not hinder the growth of lactic acid bacteria or their metabolic activities involving organic acids and monosaccharides.The study further confirmed that microbial adsorption was the primary reason for removing ginkgolic acid during probiotic fermentation.Also,the adsorption mechanism of ginkgolic acid during probiotic fermentation with macroporous resin was explored.From a mass transfer perspective,incorporating macroporous resin during the probiotic fermentation of ginkgo kernel juice reduced the mass transfer resistance for surface diffusion.Consequently,this lowered the contribution of surface diffusion to the overall diffusion process and facilitated the efficient removal of toxic ginkgolic acid.This work can help to understand the physical mechanism regarding detoxification of ginkgo kernel juice by probiotic fermentation,and offer potential strategies to enhance the safety of ginkgo kernel products.

Effects of Methacrylic Acid on Physical/Mechanical Properties and Biocompatibility of Urethane-Based Denture Biomaterials

Candida-associated denture stomatitis (CADS) is a significant clinical concern. We have demonstrated that urethane-based denture biomaterials with 10% methacrylic acid (MAA) could bind and then slowly release antifungal drug for months. Drugs on the resins could be repeatedly quenched/recharged, and in subsequent recharging, they could be changed/switched to more potent/effective ones. However, the physical/mechanical properties and biocompatibility of the new MAA-based resins are currently unknown. The objective of the current study is to evaluate the effects of copolymerization with MAA on physical/mechanical properties and biocompatibility of urethane-based denture resin materials. MAA and diurethane dimethacrylate (UDMA) were copolymerized using initiator azobisisobutyronitrile (AIBN). Water sorption and solubility were assessed with the specifications of ISO (International Standards Organization) test method 1567, flexural strength and modulus were measured according to ASTM D-790, and biocompatibility was preliminarily evaluated in cytotoxicity assay using mouse 3T3 fibroblast cells with the trypan blue method. The results demonstrated that copolymerization of UDMA with up to 10% MAA did not negatively affect water sorption/solubility, flexural strength/modulus, and biocompatibility. With 20% MAA, however, the mechanical properties of the resulting resins were significantly decreased. To sum up, UDMA-MAA copolymers with up to 10% MAA had adequate physical/mechanical properties for denture materials with no side effects on cell viability. The UDMA-MAA denture biomaterials have a good potential to be used clinically for managing CADS and other related infectious conditions.