Study On Extraction, Separation & Activity Of Active Components From Castoffs Of Citrus Grandis Osbeck

Extracting and separating active components from plants has been an important and eye-catching area in medical and pharmaceutical fields. Citrus grandis Osbeck(Shaddock)is a good,useful fruit and is widely grown in China.However,most of the time,after eating the pulp,people discard shaddock peel and shaddock seeds.It is not only wasting resources but also polluting the environment.At the same time,shaddock growers can't make enough money to keep their enthusiasm to grow shaddock continually.Based on the realties,in this dissertation,starting from the castoffs of shaddock-shaddock peel and shaddock seeds,five effective ingredients-shaddock essential oil,flavonoid,pectin,water insoluble dietary fiber and limonoids were extracted and separated out by modern extraction and separation technologies,such as enzyme-aided extraction,ultrafiltration and purification by macroporous adsorption resin.At the same time,three kinds of high-purity active compounds were obtained.Therefore,a new technical line for deep processing and comprehensive utilizing shaddock has been developed and a series of significant experimental results has been achieved.With salting-out agent 5%NaCl solution,shaddock essential oil was extracted from fragrant shaddock peel and sweet shaddock peel squeezing-vapor distillation.The yield of essential oil from fragrant shaddock peel and sweet shaddock peel was 0.935%and 0.984%, respectively.At the same time,more than thirty kinds of compounds from Jiangyong fragrant shaddock and sweet shaddock essential oil were analyzed and identified and their relative contents were determined by GC-MS.The residue of shaddock peel after the extraction of essential oil was treated by ethanol-water solution to get flavonoid,One-time extraction yield of flavonoid was 72.57%while the total yield after three times extraction was 83.09%.Macroporous adsorption resin C was used to separate the flavonoid extracts with dynamic adsorption rate 86.6%and 60%ethanol-water(v/v)was used to wash the flavonoid from resin C with the desorption rate 87.5%. As for extracting pectin from the residue of shaddock peel after the extraction of flavonoid,enzyme B-aided extraction features higher pectin yield compared with other extraction methods.After three times extractions,the pectin yield can reach 90.4%.Good decoloration effects and low pectin loss can be achieved by macroporous adsorption resin A while concentration,purification and decoloration of pectin extracts can be achieved simultaneously by ultrafiltration with inorganic tubular ceramic membrane.The pectin precipitation yield was 91.4%for salting-out agent Aluminum potassium sulfate and 95.8%for salting-out agent Ferric chloride while the pectin precipitation yield of direct ethanol precipitation method was 94.7%.The quality of shaddock peel pectin produced by enzyme B-aided extraction,which followed by ultrafiltration with inorganic tubular ceramic membrane and then spray-drying can satisfy the demands of QB2484-2000 after having been tested by Hunan quality supervision and detection institute.Extraction of water insoluble dietary fiber from the residue of shaddock peel after the extraction of pectin was studied.The water insoluble dietary fiber from shaddock peel features good quality,high coarse fiber content and light color with yield 46%or so.The proper decoloring agent for insoluble dietary fiber is 5%decoloring agent A solution.With extraction agent acetone,limonoids were extracted from shaddock seeds by percolation method and the limonoids yield was 56.88%and 41.37%for degreased seeds and non-degreased seeds, respectively.Three high-purity effective ingredients were obtained from the extracts of shaddock castoffs after further separation and purification. They were naringin(C₂₇H₃₂O₁₄·2H₂O,from flavonoid),Deacetylnomilin (C₂₆H₃₂O₈,from limonoids)and Limonin(C₂₆H₃₀O₈,from limonoids).The biological activities of shaddock essential oil on Musca domestiea and Aphis fabae and biological cativities of limonoids on Mythimna separate and Plutellla xylostera were studied.The biological activities of shaddock essential oil on Musca domestica and Aphis fabae is likely to be involved with the co-effects of limonene,citronellal and other effective ingredients while the biological activities of limonoids may be involved with their furan nucleus structure.A gel-attenuation model was set up to describe ultrafiltration membrane pollution behavior of pectin extracts.When transmembrane pressureΔP is belowΔP_opt,the ultrafiltration of pectin extracts follows gel-polarization model,flux increases with the transmemberane and the equation J=Kln(c_G/c_B)is tenable when the stable state is achieved. However,whenΔP is aboveΔP_opt,the ultrafiltration of pectin extracts follows attenuation model with the attenuation equation J=γ(ΔP)^δ(γ=5.208×10¹⁰,δ=-3.022).With this gel-attenuation model,the bell-shape relations between transmembrane pressure and membrane flux can be explained properly for the first time.The model will be helpful to guide and control the ultrafiltration of shaddock peel pectin extracts.The flow properties of shaddock peel pectin solutions were also studied.Models describing the concentration dependence and temperature dependence of viscosity of shaddock peel pectin solution were set up.The effects of temperature on viscosity of pectin solution can be described by the viscous-flow equationη=η₀exp(Ea/RT)and the average viscous-flow activation energy is 17.14kJ·mol^-1while the isothermal exponential equationη=K₂exp(A₂C)can be used to describe the effects of concentration on viscosity of pectin solution.At the same time,intrinsic viscosities of Shaddock peel pectin were determined and thus the viscosity-average molecular weights of pectin were calculated as 7×10⁴--8×10⁴ according to the intrinsic viscosity theory.The mass transfer theory was used to explain the increasing of pectin yield when pectin was extracted by countercurrent extraction-countercurrent extraction guarantees higher driving force for mass transfer,i.e.,higher concentration difference.The regularity of static adsorption of flavonoid by macroporous resin C at isothermal conditions was studied.The experimental results showed that the adsorption can be described by Langmuir equation: C_e/q_e=C_e/q₀+1/Kq₀=0.01415C_e+0.1000.The usage of salting-out agents was determined quantitatively and the salting-out mechanism of Fe³⁺and Al³⁺were studied.The results showed that the usage of salting-out agents can be calculated according to 0.1588 mol Mⁿ⁺per 100 g pectin.Fe³⁺and Al³⁺have similar salting-out mechanism-the carboxyls of pectin substitute the hydroxyls of metal hydrates,react with the metal cations and form pectin salt which precipitate from the solutions and thus separation is achieved.In conclusion,the shaddock resource is fully and comprehensively utilized:the new technical line starts from the castoffs of shaddock-shaddock peel and shaddock seeds and presents a series of products,i.e., essential oil,flavonoid,limonoids,pectin and water insoluble dietary fiber.Therefore,the study in this dissertation has offered a new way of comprehensively utilizing shaddock resources and will feature remarkable economic and social benefits and profound significance in deep processing of natural product,helping farmers to increase their incomes,promoting the shaddock growing and processing industry and modernizing Chinese medicine.