| Xinjiang pomegranate peel as the research object, the extraction, purification, nanoemulsion preparation technology and stability of polyphenols were studied. The extraction experiment of pomegranate peel polyphenols was conducted by solvent extraction, ultrasonic-assisted extraction and enzymatic treatment respectively. The optimal parameters, including extraction solvent, solid to liquid ratio, extraction time, extraction temperature, pomegranate peel particle size, extraction times, ultrasonic power, enzyme solution concentration, and enzyme solution pH, were selected. Static adsorption and desorption experiments were carried out and the suitable resin was screened from 9 macroporous absorbent resins for pomegranate peel polyphenols.The purification technology of the crude extracts by macroporous adsorbing resins were decided through the experiments, which included static, dynamic adsorption and desorption efficiency, the sample solution pH, concentration, volume, and the eluent type, dosage, flow rate, and so on. A nanoemulsion of pomegranate peel polyphenols was prepared on the base of optimization on surfactant, cosurfactant, oil and Km value by using titration with pseudo-ternary phase diagram. The morpohologic characteristics and stability of nanoemulsion with high temperature, high pressure, highlight exposure and high speed centrifugation were studied. The results showed that the three optimum extraction conditions for polyphenols from pomegranate peel were:the solvent extraction method for 50% ethanol concentration, solid to liquid ratio of 1:20 (w/V), extraction time 90min, extraction temperature 40℃, the 60 screen mesh pomegranate peel powder, extraction twice, polyphenols yield was (20.50±0.06)%(n=5); the ultrasonic extraction method:50% ethanol concentration, solid to liquid ratio 1:25(w/V), ultrasonic time 30 min, ultrasonic power 360W, polyphenols yield was (21.22±0.06)%(n=5); the enzymatic extraction:the concentration 0.25mg/mL of 2:1 cellulase and pectinase, treatment time 150min, treatment temperature 50℃, enzymolysis pH 6.0, polyphenols yield was (23.87±0.08)%(n=5). The extraction effect for enzymatic extraction was the highest, followed by ultrasonic extraction, and it was lowest for solvent extraction. However, the time consumed by the enzymatic method is the longest, and the ultrasonic method requires the least time. The ultrasonic assisted extraction of pomegranate peel polyphenols was best method. Macroporous resin SP-825 possessed the strongest absorbent ability and easier desorption property, and its optimal dynamic adsorption conditions were:the sample solution pH4.0, concentration 10.25mg/mL, sample volume 4BV, flow rate 2BV/h; the optimal desorption conditions were:eluent of 80% ethanol solution, the amount of eluent 3BV, elution flow rate 1BV/h. In optimum conditions, the pomegranate peel polyphenols average adsorption rate, desorption rate, yield and purity reached to (85.31±0.06)%, (81.14±0.11)%, (68.20±0.10)% and (32.12±0.12)%(n=3) respectively. The optimal formula of pomegranate peel polyphenols nanoemulsion is:pomegranate peel polyphenols 4.4%(w/w), EL-40 34.1%(w/w), ethanol 17.1%(w/w), IPM 5.7%(w/w), distilled water 38.7%(w/w). Pomegranate peel polyphenols nanoemulsion was clear and transparent, showed spherical (35.50±0.64) nm in diameter, uniform and stable under transmission electron microscopy (TEM). Pomegranate peel polyphenols nanoemulsion was dealt with 90℃for 10d,121℃, 1.0Mpa for 20min and 3000-40001x for 10d, the loss of pomegranate peel polyphenols were only 0.77%,0.32% and 1.33% respectively, while the loss of control were 19.45%,7.37% and 28.52%.The nanoemulsion was also limpid by high speed centrifugation. The pomegranate peel polyphenols nanoemulsion has good stability.
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