Study On Process Conditions And Properties Of Dietary Fibers From Potato Residue Modified By Different Enzymatic Method

Potato residue is a by-product of starch processing,which is rich in dietary fiber,but low in soluble dietary fiber.It needs to be modified to obtain high-quality dietary fiber.The modification method is mild and efficient in enzymatic modification.In this paper,the process conditions of enzymatically modified potato dregs dietary fiber were firstly studied.On the basis of this,to compara the composition,monosaccharide composition,physicochemical properties,structure and adsorption characteristics of the original dietary fiber from potato residue(O-DF),cellulase modified dietary fiber from potato residue(C-DF),xylanase modified dietary fiber from potato residue(X-DF)and cellulose-xylan complex enzyme modified dietary fiber from potato residue(D-DF).The research results are as follows:1.The yield of soluble dietary fiber(SDF)was used as the index.The process conditions of cellulase and xylanase modified potato dregs dietary fiber were studied by single factor test.The highest yields of SDF were 21.27%and 22.10%respectively.Based on the single factor results,the response surface methodology was used to optimize the process conditions of cellulose-xylan complex enzyme modified potato slag dietary fiber.The optimum conditions were:ratio of material to liquid 1:15(g/mL),cellulose.The enzyme addition amount was 0.41%,the xylanase addition amount was 0.40%,the pH was 5,the enzymatic hydrolysis temperature was 50?,and the enzymatic hydrolysis time was 1.55 h.Under this condition,the SDF yield was increased from 12.45%(dry potato residue)to 23.15%.2.The results of compositional determination showed that the content of cellulose and hemicellulose decreased after three kinds of enzymatic modification,and there was no significant change in lignin.Compared with O-DF,the change of D-DF was the most significant,and the cellulose and hemicellulose content decreased by 37.63%and 45.88%,respectively.The results of monosaccharide component determination showed that O-DF,C-DF,X-DF and D-DF contained five kinds of monosaccharides such as glucose,galactose,galacturonic acid,arabinose and xylose,but the content of monosaccharides in dietary fiber modified by different enzymatic methods was significantly different(p<0.05).3.The results of physicochemical properties showed that the water holding capacity,combined hydraulic power,solubility,oil holding capacity and cation exchange capacity of C-DF,X-DF and D-DF were higher than those of O-DF,and D-DF changed most significantly.Compared with O-DF,it increased by 115.22%,27.18%,45.27%,16.73%,and 173.18%,respectively.4.The results of Fourier transform infrared spectroscopy indicated that O-DF,C-DF,X-DF and D-DF all have saccharide-characteristic functional groups,and similar absorption peaks appeared at some wavelengths,but the intensity and area of absorption peaks has changed that indicating a change in the content of soluble components.X-ray diffraction curve analysis showed that C-DF,X-DF,D-DF and O-DF showed no significant changes in peak position and peak shape,and all belonged to cellulose type I.The results of scanning electron microscopy showed that compared with O-DF,C-DF,X-DF,D-DF and O-DF were destroyed,the surface became rugged,and the surface was loose and porous.The change of D-DF was the most significant.Obvious breaks and gaps,the structure is more loose.5.The results of cholesterol and glucose adsorption measurements showed that the ability of C-DF,X-DF and D-DF to adsorb cholesterol was higher than O-DF,and the ability of D-DF to adsorb cholesterol was higher than that of O-DF,C-DF and X-DF,respectively.1.28,1.10,1.09 times.When the glucose concentration was 200 mmoI/L,the ability of D-DF to adsorb glucose reached the highest 11.42 mmol/g,which was higher than X-DF,C-DF and O-DF by 0.46%,4.58%and 9.84%,respectively.