Study On Extraction, Purification And Characterization Of Pigment And Pectin From Pineapple[Ananas Comosus(L.) Merr.] Peel

The natural pigment and pectin are extractive of agricultural by-products which have wide prospect in application. In order to promote the comprehensive utilization of pineapple[Ananas Comosus(L.) Merr.] peel, the extraction, purification, component analysis and stability of pigme- nt from pineapple peel were systematically studied, and a joint production process was established for the production of pigment and pectin from pineapple peel.By single factor and orthogonal tests, 2 organic solvent extraction process of both fresh and dry pineapple peel were determined. By contrast, the process of dry pineapple peel was chosen and its process parameters were further optimized by the response surface method, the ultimate optimal process is: 75% ethanol as extraction solvent, liquid and solid ratio:60(mL/g), extraction temperature:70℃, degrees of fragmentation:through 10 meshes, the number of extraction cycles: 2, extraction time of cycle 1: 2 hours, cycle 2: 0.5 hour. The products got by applying this proce- ss are as follow: crude water-soluble pigment of pineapple peel, its total content of flavonoids: 2.451 mg/g; crude flavonoid of pineapple peel, its total content of flavonoids: 245.966 mg/g; crude oil-soluble pigment of pineapple peel, its total content of carotenoids: 3.149 mg/g.Using AB-8, D101 macroporous resin, polyamide, magnesium oxide and silica gel, the cru- de pineapple peel water-soluble pigment, flavonoid and oil-soluble pigment were refined, respec- tively. After purification, the total content of flavonoids of refined water-soluble pigment and fla- vonoid are 90.558 mg/g and 321.222 mg/g, respectively; total content of carotenoids of refined oil-soluble pigments is 7.834 mg/g. Preliminary component analysis showed that refined pineapple peel water-soluble pigment may contain flavone, flavanone and flavonol, and a low concentratio- ns of anthocyanin. Refined pineapple peel flavonoid may contain flavanone and chalcone. Refin- ed pineapple peel oil-soluble pigment has carotenoid.Results of stability experiments of pineapple peel flavonoid and water-soluble pigment showed: refined pineapple peel flavonoid is stable with heating, (sodium, calcium, magnesium, zinc)ions, sugar and Vc; astable with lighting, pH, (aluminum, copper, ferrous) ions, commonly used preservative:sodium benzoate and potassium sorbate, and oxidants. Refined pineapple peel water-soluble pigment is stable with lighting, heating, metal ions (sodium, calcium, magnesium, zinc, aluminum, copper, ferrous ion), sugar, Vc, sodium benzoate and potassium sorbate, less stable with pH and oxidant. The stability of refined pineapple peel flavonoid is good, the stability of refined pineapple peel water-soluble pigment which is more stable than the former is very good.Through single factor and orthogonal experiments, 2 pectin extraction process of pineappl- e peel powder and pineapple peel residue after pigment extraction were determined. A joint production process was established for the production of pigment and pectin from pineapple peel. Using this process, 100g pineapple peel powder(water content 11.77%) which is through 10 mesh could obtain water-soluble pigments: 1.68g, flavonoids: 0.30g, oil-soluble pigments: 0.55g, pectin: 1.12g. The content of galacturonic acid of pineapple peel pectin is 69.43%, and the quality of pectin meet national standard.