Study On Antioxidants In Premna Leaves And Preparation Of Jelly Gel With Powder Of Premna Leaves

Chou Huang Jing(Premna ligustroides Hemsl) belongs to Verbenaceae Premna Shrubs, its leaves have functions on disinfectant solution external application smear swelling, canker, etc; the pharmacological effects are related to components in Premna leaves. Premna leaves are rich in kinds of nutrients:pectin, vitamin C, amino acids, soluble sugar, crude protein, crude fat, mineral elements etc. People make it into a jelly gel for food. In this paper, we take Premna leaves as raw materials which are picked from Sichuan Dazhu area, do a series of basic reaches on nutrition indicators, flavonoids and polyphenols, volatile oils and others; Taking ascorbic acid for comparison, we measure the alcohol extract from Premna leaves oxidation resistance through scavenging ability on·OH,·O2 and DDPH and reducing power; By single factor and orthogonal experiments L9(34) of zinc gluconate, calcium chloride, citric acid concentration and drying temperature, we get the optimum conditions of green maintaining for Premna leaves. Through response surface analysis to get Premna leaves best gel technology. Research results are as follows:1) Extraction and determination for flavonoids and polyphenol in Premna leavesIn this study, taking fresh leaves as row materials, ultrasonic assisted extraction method was used to extract flavonoids and total polyphenol from Premna leaves. Aluminum nitrate assay were used to measure flavonoids and polyhneol,73.4292 mg/g was the result; Folin-Ciocalteu method for the determination of total polyphenol content, polyphenol content was 29.4403 mg/g. Quantitative determination of the linear regression equation foul Premna leaves flavonoids and polyphenols method is simple, convenient, good stability, high precision, accurate and reliable.2) Study on antioxidant activity of alcohol extracts from Premna leavesIn this study, taking alcohol extracts as experiment materials, through scavenging hydroxyl radicals (·OH), superoxide anion radical (·02), clear the DPPH radical and reducing power test of the four systems, studied the stink alcohol extract of Premna leaves resistance to oxidation. The results showed that:a) In the hydroxyl radical system, in the range of 0.0236～0.1402 mg/mL, alcohol extracts and ascorbic acid on the Fenton system generated·OH has strong scavenging ability, and with the concentration increased scavenging capacity increases. The crude extracts have slightly stronger scavenging ability of ascorbic acid.b) In the superoxide anion radical system, with increasing concentration of the extracts the clear capacity increases. Extracts of Premna leaves have better superoxide anion scavenging ability than ascorbic acid, the maximum removal rate is 48.9% when the concentration is 0.1402 mg/mL,, while the maximum removal rate of ascorbic acid is only 29.6%.c) In DPPH·Radical system, extracts of Premna leaves and ascorbic acid have strong clear ability on the DPPH·inhibition, in the range of 0.0236～0.1402 mg/mL, the clearance rate increases with increasing concentration, and the increase is big. Ascorbic acid solution on the clearance rate ie slightly higher than the extracts of Premna leaves.d) Premna leaves extracts have strong reducing power. In the range of 0.0236～0.1402 mg/mL, Premna leaves extracts, ascorbic acid concentration in the A700 value increase with the increase. After the resultant reaction of the samples the absorbance at 700 nm may reflect the antioxidant capacity, while for reducing power absorption, the stronger the greater. You can see that Premna leaves extracts have strong reducing power, and stronger than ascorbic acid.3) Analysis on volatile oil of Premna leavesIn this study, through steam distillation to get volatile oil from Premna leaves, volatile oil extracted by this is simple and the extraction rate is higher and volatile oil is pure; through gas chromatography mass spectrometer, in the given experimental conditions, we take GC-MS analysis on volatile oil of Premna leaves to get the total ion current, combined with mass spectrometry database search to identify the Premna leaves volatile components and their relative content.99 peaks were isolated and 68 compounds were identified, which account for 96.34% of total essential oil. Components which account for more than 3% include:1-octene-3-ol,1,1,5,6-tetramethyl-indene,5,8,11,14,17-eicosapentaenoic ene methyl ester, different speakers ene,α-pink thin, trans-β-Violet (blue) ones,.+/-.-trans-nerolidol, caryophyllene oxide. Contrast with volatile oil from other woody plants, Premna leaves contain mostly thin, acid, ketones, aldehydes, alcohols, esters and other ingredients. High contents of ingredients include:1-octene-3-ol (11.45%), caryophyllene oxide (9.71),α-pink rare (5.82%), and trans-β-Violet (blue) ketone (3.43%).4) Study on green-maintaining of Premna leaves in the process of drying and crushingIn this study, taking fresh leaves of Premna leaves as raw materials, by single factor and orthogonal experiments L9(34) of zinc gluconate, calcium chloride, citric acid concentration and drying temperature, we get the optimum conditions of green maintaining for Premna leaves.This study determined the final concentration of 1‰zinc gluconate and 2‰calcium chloride and 0.4‰citric acid. Dipping in intermix for 10 min at room temperature, after soaking, drain and dry it at 50℃hot air drying, samples were crushed sifted. The samples maintain the green level at room temperature for longer time.5) Premna leaves powder Jelly Gel Process based on response surface analysis By response surface analysis in this chapter, the best jelly gel process were investigated. Liquid/solid ratio, concentration of sodium carbonate and carrageenan/konjac powder affect on the gel properties, water holding capacity of gel hardness, adhesiveness. and experimental factors are related to mathematical models. The variance analysis showed that the resulting models are highly significant. Finally, the key parameters of water holding capacity for analysis, formulation of appropriate technology are selected. Liquid/solid ratio 15:1, sodium carbonate concentration 30 mM, carrageenan/konjac powder ratio of 1.6:1 is the optimism conditions. And jelly gel process made according the optimism method is stable and can be placed in at room temperature for 36 h with little changes.