Study On The Ultrasound-Assisted Extraction And Properties Of Peanut Null Dietary Fiber

In this paper, the peanut shell was used as raw material, the methods of solventextraction and ultrasonic-assisted extraction were used as extraction technology toextract the Souble Dietary Fiber from peanut shell，the isolation and puriifcation ofSDF crude extract with macroporous resins were investigated, then its properties andantioxidant activities were researched, and the paper drawed the main conclusions asfollows:1.In order to make sure the optimal conditions, this paper researched on theextraction yield of SDF from peanut shell with solvent extraction andultrasonic-assisted extraction by single factor experiments and response surfaceanalysis. The results showed that the optimal extraction condition of solventextraction as follows: granularity was100mesh, extract concentration of NaOH was5.41g/1OOmL,extraction time was4.9h，extraction temperature was79°C，solid-liquid ratio was l:16(g/mL)，and the yield of soluble dietary fiber from peanuthull was10.51%; the optimal extraction condition of ultrasonic-assisted extractionwas as follows: granularity was80mesh, solid-liquid ratio was l:14(g/mL)，extractiontemperature was60。C，ultrasonic power was480w, extraction time was40min，under the optimal condition, the yield of soluble dietary ifber from peanut shell was8.58%.2.The properties (expansive force，water binding capacity, water holdingcapacity, oil absorbability, emulsiyfing property, emulsion stability and cationexchange capacity) of SDF and IDF prepared from peanut shell by different extractionand drying methods were investigated. The results indicated that the vacuum-freezedrying had the best effect; moreover, the properties with the ultrasonic-assistedextraction were better than with the solvent extraction.3.Eight types of macroporous resins were selected to compare theirperformances in absorbing and desorbing soluble dietary ifber from peanut shell，theoptimal absorbent material for SDF was decided and its dynamic absorbing behaviorwas studied. The results showed that D101macroporous resin possesses higherabsorption and desorption capacity, and the optimal technological conditions ofad~sorpiton velocity was2mL-mml, solution concentration w"as lmg-mL"1to2mg*mL1:,solution pH was about10，and the eluting solvent was70%ethanol at1mL-min-1 lfow rate.4.The structural characteristics were identiifed by UV spectral(UV)、infraredspectral(IR) and gas chromatography(GC). The result of UV showed that the SDFcontained little protein; the result of IR indicated that the structure of the SDF wassimilar to Polysaccharide with both a-glucosidic bond and P-glucosidic bond; theresults of GC showed that the puriifed SDF contains of rhamnose，arabinose, xylose，mannose, glucose, galactose.5.Antioxidant activities of the SDF from peanut shell were evaluated, theresults showed that in the range of experiment concentrations, the scavenging capacityon DPPH, hydroxyl radical, superoxide anion and ABTS+of the puriifed SDF frompeanut shell was81.3%、82.4%、74.49%、86.1%respectively, the purified SDF shownto be more effective antioxidants in vitro and presented a certain degree of reducingpower.The effect of the SDF from peanut shell on the oxidative stability of lard oil weremeasured by the Schaal-oven method, and compared to butylated hydroxytoluene(BHT)，Vitamin C(Vc)，and tertiary butylhydroquinone (TBHQ). The result showedthat the puriifed SDF can inhibit the oxidation of lard partially. However, there issome gap compared to synthetic antioxidants, but in the early storage days, thepuriifed SDF presented equal effective antioxidants to the synthetic antioxidants.