Effect of Different Drying Methods on the Quality of Dietary Fiber by Wet Modification from Passiflora edulis Rind

Effects of drying methods on the quality of dietary fiber by wet modification from Passiflora edulis rind were studied,including hot air drying,microwave drying,vacuum freeze drying,spray drying,freeze spray drying. Results showed that the tissue structure of dietary fiber was destroyed after wet modified the morphology and colors had significantly changes by different drying methods. The dietary fiber showed excellent water holding capacity,oil holding capacity and hygroscopicity,the results were 24.1,16.4 g/g;11.8,8.3 g/g;19.3%,19.8%. The vacuum freeze drying and freeze spray drying had smaller tap density and better dispersion,solubility and adsorption properties. The angle of repose of spray dried dietary fiber was 38.5 °,showing the best fluidity. In addition the swelling capacity and cation exchange capacity had little differences between the treatments. Above all,the vacuum freeze drying and freeze spray drying had the most significant effect on the dietary fiber by wet modification from Passiflora edulis rind.