| Resistant starch(RS)is a starch that cannot be effectively digested and decomposed by the small intestine.In this study,on the basis of different raw starch materials,mung bean resistant starch(MRS)prepared using autoclave-enzymatic hydrolysis treatment and corn resistant starch(CRS,purchased)were mixed with four soluble dietary fibers(SDF,including chitosan,flaxseed gum,konjac and xanthan gum)to investigate the differences of gelatinization,morphology,and interaction properties between soluble dietary fiber and resistant starch.Based on this,the changes in texture and sensory characteristics of the composite dietary fiber meal replacement powder prepared under different addition amounts and formulas were explored for developing an optimal formula.The main research contents were list as follows:1.CRS was mixed with four kinds of SDF(chitosan,flaxseed gum,xanthan gum,and konjac gum).The pasting and rheological properties,microstructure,and X-ray diffraction spectrum of the mixed system were investigated by rapid viscosity analyzer(RVA),rheometer,scanning electron microscopy(SEM),and X-ray diffractometer(XRD).The pasting curves showed that the addition of chitosan could reduce the viscosity of CRS paste,while the flaxseed gum,xanthan gum and konjac gum increased the viscosity.All complex systems had shear thinning properties in the rheological steady flow experiments.Soluble dietary fibers significantly increased the value of viscosity coefficient(K)of the CRS,however,the value of flow characteristic index(n)was decreased with increasing concentration of soluble dietary fibers.Soluble dietary fibers addition resulted in higher storage modulus and loss modulus(G’ and G’)of CRS paste,as well as giving rise to high viscoelasticity.SEM confirmed that the addition of soluble dietary fibers made the starch granules more easily aggregated in the mixed systems.X-ray diffraction spectrum analysis showed that the addition of soluble dietary fibers did not change the B plus V type crystalline pattern of CRS,and both the concentrations and types ofsoluble dietary fibers had significant effects on the crystallinity of mixed systems.In vitro digestion experiments showed that high addition of SDF can significantly increase the RDS and SDS contents of CRS.2.The pasting,rheological properties,microstructure and in vitro digestibility of four MRS-SDF mixed systems(MRS-chitosan,linseed gum,xanthan gum and konjac gum,respectively)were studied.The pasting curve showed that the addition of chitosan could reduce the viscosity of MRS,while flaxseed gum,xanthan gum and konjac gum could increase the viscosity,and the degree of increase was successively as: KG>XG>FG.The addition of SDF can lead to greater flow resistance,make the K value of the complex system higher than MRS,and the K value increases as SDF concentration increasing.The addition of SDF significantly increased the dynamic moduli(G’,G’)of MRS.SEM indicated that MRS granules were irregular in shape and MRS/KG had larger starch granules.The addition of SDF made the aggregation degree of the compounding system more obvious.X-ray diffraction spectrum analysis showed that SDF did not change the B+V-type crystal structure of MRS,and the0.30% MRS/CT composite system had the highest relative crystallinity(55.86%).In vitro digestion experiments showed that low-dose CT and FG had no significant effect on the content of SDS in MRS,and the effect of SDF on RDS and SDS in MRS was followed as: XG>KG>FG>CT.3.The effects of RS origins,SDF species,addition amounts of SDF and xylitol on the texture and sensory properties of composite dietary fiber meal replacement powders were evaluated by single factor analysis,orthogonal experiment and sensory evaluation.The results show that the impulse property of MRS is not as good as that of CRS,which needs to be further improved.According to the orthogonal experiment,the optimal formula of meal replacement powder is: 10 g corn resistant starch,0.3 g konjac gum and 3.0 g xylitol. |
