Preliminary Study On The Interaction And Clarification Of Protein,Polysaccharide And Polyphenol In Fruit Wine

Fruit wine is a low-alcoholic beverage made from fruit juice or fruit and prepared by unique fermentation methods and techniques.It contains most essential nutrients for human life activities and metabolism:rich in vitamins,minerals,amino acids,etc.Alcohols,lipids and other nutrients not only have an effect on the flavor of fruit wine,but also have a certain nutritional supply to the human body.This paper,with gelatin,pectin and tannin as the representatives,studied the interaction between protein and polysaccharide,protein and polyphenol,and tried to explore the causes and mechanism of fruit wine turbidity.Through the research of predecessors and own research,the chitosan/graphene oxide/sodium alginate?CS-GO-SA?adsorption material with the ability to adsorb multiple substances is synthesized.The morphology and structure of the composite is analyzed by SEM,FTIR and XRD.BSA and Cu²⁺were used as adsorption targets to study their adsorption effects,adsorption mechanism and establish relevant adsorption models to determine whether the materials are suitable for actual wine samples and predict it is clarification effects.The previous experiments confirmed that the adsorbed materials were used in actual fruit wine for clarification.Optimize the experiment,the specific research content is as follows:?1?The interaction between gelatin and pectin is studied by turbidity measurement,dynamic light scattering technique,fluid property analysis,and isothermal titration calorimetry?ITC?.The results show that the ratio of the two in the gelatin/pectin complex solution will affect the formation of the complex and the closer the solution pH is to the isoelectric point,the greater the turbidity of the complex solution.The low concentration of salt ions will promote the interaction between gelatin and pectin.The high concentration of salt ions is the opposite;the gelatin/pectin composite solution is a non-Newtonian fluid with shear thinning phenomenon,and the gelatin/pectin complex structure is destroyed under shaking conditions,and the gelatin and fruit are confirmed by isothermal titration calorimetry.The glue mainly consists of electrostatic interaction??H=-10.84±1.44 cal/moL<0,?S=4.15 cal/moL/deg>0?,which is an exothermic process??G<0?.?2?Using gelatin and tannin as a representative for the interaction between protein and polyphenol,it was found that the UV absorption peak of gelatin/tannin complex is at 280 nm and 234 nm,and it is presumed that hydrogen bond acts between them;The determination shows that the gelatin/tannin composite solution has the highest turbidity?the most complex is formed?when the ratio is 1:1,and the complexation reaction between the two is reversible reaction affected by temperature;gelatin/tannin the composite solution belongs to non-Newtonian fluid,and its viscosity decreases with the increase of shear rate.Under the oscillating environment,the formed composite structure is destroyed.The isothermal titration shows that the interaction between gelatin and tannin is mainly hydrogen bond and van der Waals.Force??H=-6.37±1.415cal/moL<0,?S=-0.12 cal/moL/deg<0?,and is an exothermic process??G<0?.?3?Summarizing the predecessors'research and previous experiments,it is found that protein is an important cause of fruit wine turbidity?Forming complexes with substances such as polyphenols and sugars in fruit wines and the structures are destroyed under the shock of external force?,and its removal will not have a significant impact on the flavor of fruit wine.Therefore,chitosan/graphene oxide/sodium alginate adsorbent?hereinafter referred to as CS-GO-SA?,which has protein adsorption and mainly adsorbed by various substances,is synthesized and characterized by SEM,FTIR and XRD.Morphological and structural analysis,using bovine serum albumin?BSA?and Cu²⁺as adsorption targets to explore its adsorption mechanism and effect,and establish an adsorption model to determine whether the materials are suitable for actual wine samples and predict their clarification effects.The results show that:Under the optimal adsorption conditions,the adsorption amount of BSA was 740.7 mg/g;the adsorption amount of Cu²⁺was 246.775 mg/g.The adsorption behavior of both was consistent with the Lammguir adsorption isotherm model and the first-order kinetic model and the adsorption process was exothermic,CS-GO-SA material is mainly single-layer uniform adsorption,which is affected by physical factors.This is similar to the adsorption mode and mechanism of the existing wine clarifying agent,indicating that the material is suitable for clarification of fruit wine,and its good adsorption effect and adsorption diversity also let us speculated that the material has a better clarifying effect on the wine.?4?Through the previous study,the CS-GO-SA material was used for the actual wine clarification,and the best clarification conditions were obtained:CS-GO-SA material 0.55 mg/mL,time 65 min,temperature 41?,pH=4.2,fruit wine The turbidity was reduced to 1.762 NTU.Through the response surface find the pH and CS-GO-SA materials had the greatest influence on the clarification of wine,and the CS-GO-SA material has good reusability and can stabilize the wine for a period of time after clarification of the wine.