Modification Analysis Of Soluble Dietary Fiber From Dendrobium Officinale Residue And Its Application In Jelly

Dietary fibres have good physicochemical as well as functional properties.In order to enhance the utilisation value of Dendrobium officinale processing by-products,SDF was extracted from the residue of Dendrobium officinale,a medicinal food plant,and the extraction process was optimised using response surface methodology to enhance the yield of SDF.Based on the optimal process conditions of extraction by high-temperature cooking,the SDF was modified in combination with ultrasonic method,alkaline hydrogen peroxide method and ultra-micro pulverization method,and the differences in structural characteristics and functional properties of the SDF with different modifications were explored,and the effects of SDF addition to jelly on its texture,rheology,colour,taste and functional properties were investigated.(1)Based on the single factor results,using the yield of SDF as the response value,the Box-Behnken response surface was used to optimize the process conditions for extracting SDF.The optimal extraction conditions were determined as follows:high-temperature cooking time 38 min,temperature 125 ℃,and material liquid ratio1:59.(2)High temperature cooking method combined with ultrasonic method,alkaline hydrogen peroxide method,and ultra-fine grinding method were used for modification treatment.It was found that the proportion and type of HUSDF monosaccharides after modification changed,their molecular weight decreased,their microstructure became more porous,and they had good water holding,oil holding,adsorption capacity of glucose and sodium cholate and nitrite,and antioxidant capacity.However,HASDF was microscopically fragmented and tightly stacked together,with higher crystallinity giving it better thermal stability and no significant improvement in functional properties.It was speculated that the dense fragmented microstructure and higher crystallinity may also hinder the diffusion and adsorption of molecules.HSSDF exhibited the best antioxidant capacity,possibly due to the physical effect of ultrafine crushing,which promoted the release of phenolic substances in the raw material and significantly improved the ability to scavenge free radicals;smaller particle sizes could easily aggregate,and the structure would closely connect,which had a certain impact on functional characteristics.However,compared to WTSDF,water and oil retention and adsorption characteristics also had a significant improvement.(3)The orthogonal test optimized the preparation formula of Dendrobium officinale jelly,mainly based on the sensory evaluation results,to explore the sensory effects of four factors on Dendrobium officinale jelly.The final optimal combination of Dendrobium officinale jelly was: the addition amount of Dendrobium officinale was 30%,the addition amount of white granulated sugar was 14%,the addition amount of citric acid was 0.10%,and the addition amount of composite rubber powder was 1.3%.Based on previous research results on dietary fiber prepared by high-temperature cooking combined with ultrasound,it was known that HUSDF had good hydration properties and functional activity characteristics,which could give Dendrobium officinale jelly a better taste,and changed the viscosity and texture of food.Therefore,this study added HUSDF to jelly and found that its texture characteristics were significantly improved,and the intervention of HUSDF could endow jelly with better chewiness and elasticity.The rheological results indicated that the yield stress of the jelly increased and the ability to resist external forces increases,which would be more conducive to the transportation of the jelly.In addition,the consistency coefficient of the jelly sample increased,which indicated that the interaction between HUSDF and the gel system increased the viscosity,which was conducive to enhancing the inhibition of α-amylase and the binding of glucose and sodium cholate molecules,thus having a positive effect on the functional properties of the jelly.According to the SEM observation results,it could be seen that the microstructure of Jelly-S was loose and had obvious pores,indicating that the addition of dietary fiber helps to adsorb free water in the jelly,thereby giving the jelly a better taste and longer storage life.