Study On The Extraction Of Essential Oil And Isolation Of Pigment From The Peel Of Guanxi Pomelo

Guanxi pomelo is a kind of well known traditional fruit in Pinghe County, and one of the famous varieties of pomelo in China. In 2009, 43000 hm2 of Guanxi pomelo has planted in the whole county, with 800000 tons of annual output and increasing year by year. As a result, more and more pomelo is used to process. High content of essential oil and pigments is in the external part of pomelo peel. By extracting essential oil and pigments, it will not only improve the added-value of Guanxi pomelo, but also reduce the pollution of the environment and resource waste. In this paper, the external part of Guanxi pomelo peel was used as the raw material to study the processing technology and the components of essential oil and pigment.In the thesis, the hydro-distillation (HD) technology of essential oil were studied. The results showed that the optimum operation conditions were extracting time 30min, degree of fragmentation D, solid to liquid ratio 1:35 (OD value). The yield of essential oil on dry basis was 3.945% under this condition. The results of GC-MS, GC-MS-O and sensory evaluation showed that the main components of characteristic flavor in Guanxi pomelo peel essential oil were bornylene, (Z)-3,7-dimethyl-1,3,6-Octatriene, (E)-4,8-dimethyl-1,3,7-nonatriene, L-linalool, farnesol, trans-caryophyllene, 4-methyl-1-(1-methylethyl)-3-cyclohexen-1-ol, hexanoic acid, hexyl ester,α-terpineol, germacrene-D, hexyl octanoate, nootkatone,β-myrcene, limonene, decanal and nerol.Pigment was separated by macroporous resin. AB-8 resin was selected by static adsorption and desorption experiments (resin 0.2g, volume of pigment 50mL). The results showed that the equilibrium adsorption rate was 57.40% and the equilibrium adsorption rate was 97.65%. Chromatographic column (16×450mm) was used for dynamic experiment. The results showed that the optimum adsorption conditions were temperature 25℃, concentration 1.312, column height to diameter ratio 12:1 and flow rate 4BV/h. The adsorption rate processing 8BV is 91.44% under this condition. The optimum desorption conditions were temperature 25℃, eluted by 70% ethanol and flow rate 4BV/h. The desorption rate is 99.47% under this condition. The result of resin reusability experiment showed that AB-8 resin can be long-term reused. The adsorption rate only fell 1.56% after 21 times resin regeneraton.The components of the pigment were analyzed by color reaction, TLC, UV-VIS and HPLC-MS. The results showed that the pigment's component is the flavonoids, and the main component is naringin which is 70% of the total amount. The results of pigment stability experiment showed that the pigment is stable under 100℃, pH3-12 and common food additives.