Studies On Extraction, Purification And Characteristics Of Flavonoids In Lotus Leaf

Besides regular components, such as carbohydrates, lipid and protein, loatus leaves alsorich in a variety of alkaloids and flavonoids.Using lotus leaves as raw material, this paper studied extraction process, separation andpurification and characteristics of flavonoids in lotus leaves, In the meantime, this paperidentified the flavonoids in lotus leaves extractive by the method of color reaction..According to experiments, the main results were as follows:（1）Considering the yield of general flavones, we extracted general flavones using themethods of ultrasonic-assisted extraction and ultra-micro shatter, and employed responsesurface to design these experiments. Then, a mathematical model for extracting technologicalparameters was established, and the optimal extracting technological condition was achieved,which was that screen number was170（diameter was0.09mm）, soak time was8h, ethanolconcentration was60%, ultrasound time was29min, solid-to-liquid ratio was1:39Under thisoptimal condition, the yield of general flavones was10.55%.（2）We researched the stabilities of light fastness, heat fastness, pH, anti-metal ions, foodaddictives of lotus leaf extract, and used incremental analysis to study stability impact of lightand heat to lotus flavone. The result showed that lotus flavone was stable when temperaturewas80℃and pH was6-8, the influence of carbohydrates to lotus flavones was unobvious,metal ions had certain effect to the stability of flavones, Cu²⁺，Mg²⁺、Ca²⁺、Fe³⁺influencedlotus flavones much, while the impact of K+and Na+ions was stable. Incremental analysiswas used to study the influence on light and temperature on the lotus leaf flavonoids and it’sabsorbance. Results showed that the influence of temperature on lotus leaf flavonoidsabsorbency was more significant than its impact on light; two-factor repeated experimentanova was used to study the influence on light and temperature of the lotus leaf flavonoids pH,the results showed that the temperature on the lotus leaf flavonoid pH was relatively light onthe influence of the impact is more significant.（3）The abilities of four kinds macroporous resins adsorbing and desorbing flavonoids inlotus leaves were analyzed. The dynamic absorbing process of D101resin was studied,throught which the optimal process was obtained as: the pH was6, elution solution concentration was0.787mg/mL, flow rate of absorption solution was2BV/h, eluent was50%ethanol, flow rate was2BV/h, and dosage was3BV. By ultraviolet spectrophotometry, theunpurified flavonoid concentration was0.0978mg/mL, while purified flavonoidconcentration was0.1556mg/mL, which increased by59.1%than the previous one.（4）High performance liquid chromatography （HPLC） was used to study purified andnon-purified lotus leaf flavones respectively. Four flavone substances were detected innon-purified lotus leaf flavones, which were catechinic acid, rutin, myricetin and quercetin,while five flavone substances were found in the purified one, which were catechinic acid,rutin, myricetin, quercetin and luteolin. The content of these five flavone substances increasedsignificantly in the purified one. Myricetin and luteolin were found for the first time inflavone extracting solution, which could infer that flavone extracting solution of lotus leafmight contain these two substances.（5）The result of antibacterial experiment showed that crude flavone had certainbacteriostasis to coli, fluorescent pseudomonas, pseudomonas aeruginosa, yeasts, and thebacteriostasis rose as its concentration increased; however, it had no bacteriostasis to branchmold. The experimental result revealed that the minimal antibacterial concentrations to E.coli,pseudomonas fluorescens, pseudomonas aeruginosa and yeast were6.250mg/mL,3.125mg/mL,1.562mg/mL,12.50mg/mL respectively, and that the minimum bactericidalconcentrations to E.coli, pseudomonas fluorescens, pseudomonas aeruginosa and yeast were12.50mg/mL,6.250mg/mL,3.125mg/mL,25.00mg/mL.（6） Uesed chilled meat pork as test materials, through the determination of the totalnumber of storage of bacteria, pH value and TVB-N, and sensory evaluation index of thecomprehensive on a regular basis. The experimental results showed that lotus leaf flavonoidsextract can effectively delay the specimens pH change, can significantly inhibit the growth ofthe bacteria, and it also showed that the higher flavonoid concentration is, the better effectwas got. Towards effect of preservation, Nisin was best, the next one was lotus leaf flavonoidsextractive, Sodium Dehydraacetate was the third, while potassium sorbate was worst.