The Preliminary Study On Functional Characteristics Of Dried Persimmon Frost And Persimmon Polysaccharide

The white crystalline powder attaching to the surface of dried persimmon is named dried persimmon frost (DPF), which is regarded as the quintessence of persimmon. The practical applications show that DPF has good health valueand medicinal value, but the the chemical composition, modern medicine and nutriology function have not been completely clarified. In this work, we had identified the main composition and antioxidant properties of natural DPF, compared the antioxidant and antimicrobial action of natural and artificial DPF. Then, we took fresh persimmon as material to study the extraction, isolation, purification and antioxidant action of persimmon polysaccharide (PP) with a view to clarify the functional characteristics of DPF and PP. The main study results were as follows:1. The chemical compositions of DPF hydrolysate were studied by HPLC etc. The results indicated that Niuxin DPF/ Jingmian DPF mainly consisted of sucrose 2.46/0.79 mg/g, glucose 612.41/515.24 mg/g, fructose 85.87/74.97 mg/g, mannose 4.14/2.82 mg/g, mannitol 0/1.08 mg/g, sorbitol 0.29/0.16 mg/g, protein 12.61/0.17 mg/g, fat 82.48/77.98 mg/g, polyphenol 0.70/0.77 mg/g, polysaccharide 6.70/13.12 mg/g.2. The antioxidant properties of DPF were evaluated through FRAP, hydroxyl radical and DPPH radical scavenging abilities. The results showed that the total antioxidant ability of Niuxin DPF/Jingmian DPF were equivalent to 31.95±0.05/39.46±0.18mg/mL FeSO₄, the hydroxyl radical scavenging effect were 85.96±0.01/89.80±0.59 % and the DPPH radical scavenging effect were 94.12±1.26/94.71±0.33 %. Thereinto PP had high antioxidant ability.3. Both natural persimmon frost and artificial persimmon frost had antioxidant properties, and the total anti-oxidation, DPPH·and·OH removal capacity of artificial persimmon frost were stronger than that of natural persimmon frost. The results showed that the polysaccharide, polyphenol and total flavonoids contents contributed significantly to the antioxidant activities in DPF. Crude PP had antimicrobial effects. It (20 mg/mL) showed antimicrobial effects to E.coli,Aspergillus Niger, Hansenula anomala, Micrococcus Luteus, Staphylococcus Aureus, and the inhibition-zone diameters were 20.32±1.23, 13.33±1.53, 11.00±0.00, 8.67±0.58, 8.00±0.52 mm.4. The optimal extraction parameters of crude PP by ultrasonic aided water extraction method were ultrasonic power 900 W, ultrasonic treatment time 3 min and water multiple 20, while the extraction rate of crude PP was 13.35±0.27%. Four PP fractions (PP I, II-a, III, and IV-b) were separated by using a DEAE anion?exchange column and a Sephadex G?200 column. Due to the eluting peak were symmetric, the purification effect was up to ideal. The antioxidant properties of PPIV-b were strongest in the four fractions. The total antioxidant ability of PPIV-b (10 mg/mL) was equivalent to 137.17±10.25 mg/mL FeSO₄, the EC₅₀ values of hydroxyl radical scavenging effect and DPPH radical scavenging effect were 0.37±0.02 mg/mL and 4.45±0.07 mg/mL.