| Zizyphus jujube cv.Yuanlingzao is one of the eight main jujube varieties in China and is an important dry-processed variety in Shandong Province.Zizyphus jujube cv.Yuanlingzao has anti-cancer,anti-inflammatory,immune and anti-oxidation health effects.It is rich in polysaccharides,flavonoids,saponins,polyphenols and other functional ingredients.Studying the antioxidative components and characteristics of Yuanlingzao in-depth has theoretical and practical significances for clarifying the mechanism of antioxidation and promoting product development.In this paper,the extraction of polyphenols,flavonoids and saponins from jujube was studied.The isolation and purification of polyphenols,the identification of their components,the antioxidant properties of active ingredients were studied.Changes in antioxidant composition and antioxidant properties during juice processing were studied.The main findings and conclusions were as follows:1.Extraction methods and conditions optimization of biological active ingredients in jujube: Ultrasonic extraction was used to extract polyphenols and flavonoids.The optimized extraction conditions of polyphenols were ethanol concentration of 50%,extraction time of 30 min,solid-liquid ratio of 1:15,ultrasonic power of 300 W,extraction temperature of 60 °C.The experimental yield was 1.897% ± 0.006 and the yield of dried dates was 1.191%;The optimized extraction conditions of flavonoids were ethanol concentration of 70%,extraction temperature of 60°C,solid-liquid ratio of 1:20,ultrasonic power of 450 W,extraction time of 30 min.The yield was 0.301% ± 0.007 and the yield of dried dates was 0.189%.The optimized conditions for extracting saponins from water bath were as follows: solid-liquid ratio 1:05,ethanol concentration 80%,and extraction temperature 70°C.The yield was 4.832% ± 0.0072 and the yield of dried dates was 3.034%.2.Separation and purification of jujube polyphenols: The separation and purification process parameters was polyphenol concentration of 1 mg/mL,sampling amount of 50 mL,eluted with a concentration of 60% ethanol,using HP-20 macroporous resin.Collected and get polyphenol crude samples.The polyphenols were further separated using Sephadex LH-20 and eluted with 60% ethanol.The purified polyphenols had greater antioxidant capacity than before.The crude polyphenols purified by the resin contained six substances: gallic acid,protocatechuic acid,catechin,chlorogenic acid,ferulic acid and rutin.The purified polyphenols purified by sephadex contained protocatechuic acid and ferulic acid.The final content of the protocatechuic acid was 0.114 mg/g and ferulic acid was 0.022 mg/g.3.Antioxidant properties of active ingredients: The iron ion reduction capacity and DPPH radical,hydroxyl radical and superoxide anion radical scavenging ability tests were used to determine the antioxidant activity of polysaccharides,polyphenols,flavonoids and saponins and compare their antioxidant capacity.The results showed that the total antioxidant capacity of polyphenols were the strongest,followed by flavonoids;saponins and polysaccharides were small.There were significant dose-effect relationships in the free radical scavenging capacity and the reduce capacity.4.Changes in antioxidant composition and antioxidant capacity during the processing of jujube juice: the content of antioxidants gradually decreases during enzymolysis to sterilization.Enzymolysis and decolorization are the key processes affecting the change of active ingredients;the antioxidant activity of jujube juice gradually decreases from beating to sterilization.Decolorization,enzymolysis and clarification were the key processes affecting the change of antioxidant activity;polysaccharides,polyphenols and saponins are the main components that affect the change of antioxidant capacity of jujube juice,and they have significant positive correlations with reducing ability,hydroxyl radical scavenging rate,and superoxide anion radical scavenging rate.Flavonoid content was significantly positively correlated with DPPH free radical scavenging rate.have significant positive correlations with... |
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