Primary Study On Extraction And Utilization Of Antioxidant Components From Almond Skin

Almond skin is the by-product of almond processing. It is red brown and small, tastes pain. Almond skin includes many kinds of polyphenol compound which has antioxidative capacity and health functions. This thesis draws up the extracting, purification and activities of substance in almond skin.The parameters of the optimal extracting technology included ethanol concentration 60%(v/v), extracting temperature 60℃, ratio of sample to extracting solution 1:30 (w/v) and extracting time 4 h through the single-factor experiments and orthogonal experiments. AB-8 was the optimal purifying resin based on absorption content and the ratio of elution. The antioxidants purified by the resin of AB-8 from almond skin have strong antioxidative capacity.The total polyphenols content of the almond skin was determined and it was concluded that the total polyphenols content of per gram dry almond skin was 4.6%. The parameters of the optimal extracting technology included concentration of ethanol 70% (v/v), extracting temperature 70℃, ratio of sample to extracting solution l:30(w/v) and extracting time 3 h through the single-factor experiments and orthogonal experiments of hot extraction and the ultrasonic wave extraction.The purification of almond skin polyphenols was studied. The macroporous adsorption resin AB-8 was selected as exclusive separation resin of almond skin polyphenols. The adsorption density was 2.5 mg/ml, the adsorption velocity 3 mL/min, the elution velocity 1.5 mL/min, the eluent density 80% and the elution solvent 5 BV. Then the optimized elution was dehydrated by vacuum freezing drying. The almond skin polyphenol powder was collected. After the purification, the yield rate of almond skin in product was 65.2%. The almond skin polyphenols in product detected by TLC was polyphenols. Investigated the total polyphenol of almond skin using thin layer chromatography and HPLC. Contrasted the anti-oxidation activity of total polyphenol of almond skin and the total polyphenol of Toona sinensis, the extraction of gingko leaf and the polyphenol of tea through the TCA, the FRAP and the DPPH experiment. The total polyphenol of almond skin has the highest anti-oxidation ability.Anti-oxidation constituent of almond skin were extracted by using different polar solvents, which were added into soybean salad oil, for determination of peroxide value (PV), conjugated diolefine (CD) and conjugate three alkene (CT) value. The total polyphenol of almond skin can substitute for BHT as antioxidant in soybean salad oil to delay oil oxidation.