Research On The Preparation For Potato Resistant Starch By Microwave-enzyme Method And Application In Yogurt

In this paper, the experiments were held with potato starch as materials, the method of microwave-enzyme was used for the preparation of potato resistant starch. On the basis of single factor experiment to microwave conditions, enzyme solution conditions and retrograded conditions, adopt the orthogonal experiment to optimize the process parameters to determine the best microwave-enzyme solution process. On this basis, test physical and chemical properties of potato resistant starch, and add it to the yogurt, research how influence the quality. The specific research results are as follows:(1) On the basis of single factor experiment, by orthogonal experiment optimization, determined the best technological conditions which adopt microwave-enzymatic hydrolysis for potato resistant starch are:powders concentration15%, microwave effect time90S, microwave effect power800W, thermostable a-amylase quantity lOCU/g dry starch, thermostable a-amylase effect time30min, pullulanase quantity0.10PUN(G)/g dry starch, pullulanase effect time6h, pullulanase action temperature55℃, on the condition of4℃retrograded24h. Under such conditions to repeat validation RS yield is up to17.2%.(2)The scanning electron microscopy (SEM) was used to observe the surface morphology of potato resistant starch and discovery that, compared with the potato starch, the original smooth surface disappears, produced in irregular form; the potato resistant starch produced by microwave-enzyme has more stronger crystalline than that produced by enzyme. Under test the rheological properties of potato resistant starch found that, compared with the potato starch, the water-holding capacity of potato resistant starch is up by72.4%, the bibulous rate is up by24.64%; the emulsification ability of potato resistant starch is reduced by14.85%, emulsified stability is reduced by14.61%. Determination the Brabender viscosity curve, found that potato resistant starch gelatinization more difficult than resistant starch, the paste viscosity also far lower than the original starch, but viscosity stability and gel ability is stronger than potato starch. Under the determination of acid resistance, found that potato resistant starch has strong resistant acid feature, can be used in acidic foods widely.(3)By researching the application effect of yogurt, which was added potato resistant starch, found that potato resistant starch is more suitable to add in yogurt than sodium carboxy methyl cellulose(CMC); potato resistant starch blend use with pectin can supplement each other, they are not suitable for working as thickening and stabilizer; along with the increase of potato resistant starch quantity, the compatibility effect of mixed pectin is more better; when the concentration of potato resistant starch is1.2%, pectin added content is0.04%, the yogurt has best quality.