Preparation And Characteristics Of Water-soluble Dietary Fiber From Coffee Peel

In recent years,the growing area of coffee in China has been expanding year by year,and the output of coffee by-products is very large.However,there is no effective industrial reuse link,and there is also a lack of potential products for the development of by-products.This paper mainly studied the preparation process of water-soluble dietary fiber from the peel of the coffee from Yunnan small grains and differences in physicochemical properties after enzymatic modification,using dried coffee peel powder as raw material,based on enzyme modification,assist with four different pre-processing methods,like ultrasound-assisted method,microwave-assisted method,wet crushing aid method,and high-pressure blasting aid method,to get Changes in functional properties and structural characterization of samples obtained by enzymatic and four combinations methods situation.(1)The dry powder of coffee bean peel was crushed into different particle sizes,and the particle size was from 20 mesh to 120 mesh,as the particle size gradually increased,that is,the actual particle size of the skin powder became smaller and smaller,and the extraction rate of water soluble dietary fiber from the coffee peel increased first and then decreased,among them,the peak particle size was 60 mesh,and it was concluded that the raw material treatment for extraction of water-soluble dietary fiber from coffee peel should be about 60 mesh.(2)The yield of water-soluble dietary fiber from coffee peel was used as the index,Through single factor and response surface analysis,it was determined that the extraction process of water-soluble dietary fiber from coffee peel by cellulose enzymatic method was:1.12%of cellulose;pH 4.87;The enzymolysis reaction time was 2.27h and the enzymolysis reaction temperature was 49.08℃.(3)Comparing the basic composition,dietary fiber composition and hydration properties of the dietary fibers from the coffee peel and modified by the the cellulose,the obvious results are that the ratio of dietary fiber to total sugar was lower than that of peel powder;in addition,the total dietary fiber content in the modified samples was significantly higher than that in the peel samples,and the ratio of water-soluble and water-insoluble dietary fibers increased;finally,according to the results of the hydration properties,the dietary fiber after modification obviously has higher water holding capacity,water binding capacity and swelling properties than the pre-modified peel powder.(4)The water-soluble dietary fiber of the cellulose enzymatic method was compared with the water-soluble dietary fiber based on the cellulase method assisted by the four pretreatment methods.The results of the yield showed that the wet grinding group>high pressure blasting group>ultrasonic group>microwave group>enzymatic black group,the highest wet grinding rate is 14.65%;on the color,the brightness of the products is dark,the color is reddish brown,moderate yellowish,the color difference value is displayed,the total color difference value of the microwave treatment group is the largest,3.691,using the decoloring agent to decolorize,The results showed that the hydrogen peroxide oxidation method was significantly higher than the activated carbon physical adsorption method;with respect to water holding capacity,swelling capacity,oil absorption capacity,adsorption capacity for cholesterol,adsorption capacity for heavy ions,cation exchange capacity and antioxidant capacity,the experimental group was superior to the control group in varying degrees.(5)Compared with the enzymatic and combinatorial methods,the ultrastructure showed that different pretreatment methods had different degrees of structural damage and surface area increase;the infrared spectra showed that the experimental group and the control group were basically the same;In the monosaccharide analysis,the monosaccharide composition in each group was mainly rhamnose,arabinose,talose,mannose,and galactose;the heat flow and rheological curves showed that the curves of each group were extremely similar.In this experiment,for the first time,four combinations were applied to the extraction of coffee peel fiber,and the enzymatic process was optimized and the characteristics of the fiber product were determined.This provided a theoretical basis for the research of the new fiber additive.