Dietary Fiber Contents and Physicochemical Characteristics of Fiber-Rich Powder from Pitaya (Hylocereus undatus) Peel

Dietary fiber-rich powder from piyata peel(DFRPP) with three different particle sizes(DFRPP80,DFRPP140 and DFRPP250) was prepared.The contents of total dietary fiber(TDF),soluble dietary fiber(SDF) and insoluble dietary fiber(IDF) were determined.The physicochemical characteristics of DFRPP were also investigated.The results showed that the contents of TDF and SDF in DFRPP140 with particle size of 58—104 μm revealed the highest level,which were 79.37% and 33.07%,respectively.DFRPP140 showed a good SDF/IDF ratio and the strongest water-holding capacity(WHC,54.20 g/g),oil-holding capacity(OHC,2.65 g/g) and swelling capacity(SC,50.63 mL/g).Moreover,DFRPP140 had the best glucose dialysis retardation index(GDRI),which was 60.24%,59.24% and 62.83% at 20,40 min and 60 min,respectively.These findings suggest that DFRPP140 can be seen as an excellent source of dietary fiber for foods.