Study On Extraction, Purification And Functional Activity

Piper nigrum L, an evergreen plant, belongs to Piperaceae and Piper. Pepper is known as the king of tropical spices. Piperine, as an important material of pepper aroma and functional component, has anti-inflammatory, anti-bacterial and anti-cancer activities. This research mainly studied the extraction process, purification and antioxidation of piperine. After that, an oil-in-water emulsion was prepared and evaluated its antimicrobial action. The research results were as follows:1. Determination of pepper compositions. Contents of moisture, polysaccharide, total fiber, fat, ash and protein of black and white pepper were determined. Then, piperine crude extract was analyzed by the gas chromatography mass spectrometry. The results showed that contents of moisture, polysaccharide and total fiber in black pepper were obviously lower than white pepper. Conversely, the contents of fat, ash and protein in black pepper were higher. And in the piperine crude extract from white pepper, piperine relative content was 67.04%. Besides that, many other compositions such as Methyl trans-cinnamate,1,2,3,4-Tetrahydrophenanthren-9-ol, Caryophyllene and a-Copaene were significant to aroma components of pepper.2. Extraction process of piperine. The three different extraction methods for piperine from black and white pepper were compared by UV spectrophotometry. The optimal process conditions were explored by single factor and optimization tests. For white pepper, the optimized ultrasonic extraction, enzymatic extraction and ultrasonic-assisted enzymatic extraction presented piperine yields of 5.80%,5.29% and 6.44%. For black pepper, the piperine yields were 5.41%,4.59% and 5.70%, respectively. The results showed that ultrasonic-assisted enzymatic extraction for piperine was better relatively.3. Purification of piperine extracted from white pepper. HPD 722 resin was selected out of 5 types of HPD macroporous resins. It studied the effects of piperine concentration, ethanol concentration and sample flow velocity on adsorption and desorption capabilities through the static and dynamic tests. The results showed that the optimum process conditions for purifying piperine using HPD 722 resin were as follows:sample concentration 2.6 mg/mL, flow velocity 3 mL/min, the maximum injection volume 110 mL, and amount of absolute ethanol as desorption solvent 200 mL. Under such conditions, the adsorption ratio was 53.06%, desorption ratio was 69.01%, yield of piperine could reach 36.62%, and piperine relative content was 95.47%.4. Antioxidant activity of piperine. It revealed the piperine had good scavenging effects on DPPH free radicals and hydroxyl radicals. When the concentration of piperine was 2 g/L and 20 g/L respectively, it could remove about 90% of DPPH free radicals and hydroxyl radicals. But piperine showed significantly lower ability on reducing power and total antioxidant activity than Vc and BHT. Besides, the piperine had better anti-lipid peroxidation effect. And the piperine of 3 g/L had almost the same antioxidant activity as BHT of 1 g/L.5. Antibacterial activity of piperine emulsion. The oil-in-water piperine emulsion with CMC and maltodextrin was prepared. The optimum proportion was CMC 0.5%, CMC and maltodextrin ratio 1:25, piperine solution 1.5%. Under these conditions, piperine emulsion had a fine centrifugal stability. Then, piperine emulsion had a certain degree of antibacterial effect on Staphylococcus aureus and Escherichia coli by antibacterial experiment.