| Pectin is a kind of gelatine polysaccharides from the plant tissues, itconcludes protopectin, pectinic acid and pectic pectin. It is in the leaf, peal, culm ofplant. Pectin is used in food industry as gellatification, emulsification, adding denseagent etc. in addition, it also can reduce blood fat and adsorb poisonous metal ion in themedication. We must import pectin in order for industy requirement. Apple pomaceincludes about 15% pectin, and apple pomace is very abundant and concentrative in ourcountry, Every year we can produce apple pomace 0.9 million tons. So there is gloriousprospect to produce pectin utilizing apple pomace. And we also can resolvecontaminative question brought with apple pomace, improving the plus value of applepomace.In the paper, the following contents were particularly studied:Firstly, we ensured the standard of raw material, and suitable acid solvent to extractpectin, the quantitative method for total pectin content was researched, which concludesthe condition of acid degrading and showing color.Secondly, we got the optimal conditions of different extracted methods, concludingultrasonic-assisted extraction, microwave-assisted extraction, and resin-assistedextraction. And we compared their excellence and defect.Thirdly, We ensure the purification conditions of every methodForthly, we research how to precipitate pectin.At last, we studied the gelling characteristic of different molecular weight pectinwhich are separated with microfiltrating.Through a good many of experiment, we can draw conclusions as follows:ⅰwe decided HCl as extraction reagent, and raw material should be 60mu; total contentof pectin is quantitatively determined by means of carbazole spectrophotometricmethods which forms a highly stable blue color and with sufficient precision andreggedness. Galacturonic acid was used as standard substance, and there is a very goodlinearity when the concentration of galacturonic acid changing from 0-70mg/L, thestandard curve equation is Y=0.0115x-0.0099, and R2=0.9995.ⅱIn the process of extracting pectin with changed frequency ultrasonic. We found thebest extracted conditions: pH 1.5, Temperature 70℃, frequency 80kHz, solid:liquid ratio 1:15. Extracting ratio was 12.19%. in the process of extracting pectin withmicrowave radiation, we found that solid:liquid ratio is the most important effectingfactor, the next is time, pH value, temperature. The better extracting conditions were 40of solution/material, pH value 1.3, 65℃of temperature and 35min of time. By theabove condition, the extraction rate of pectin can be 10.81%. there have been manystudies on extracting pectin by ion exchange resin(IER). In this paper, we found thatmany factors effected pectin yield. The most irportant is solid:liquid ratio and extractingtemperature, the next is pH value, extracting time, the quantity of resin. The optimalextracting condition:solid:liquid ration keeps 1:30, with 0.03 part IER(001×7)at 85℃,pH 1.4, extract for 2.5h. the quality indexes of the product reach or surpass thoseformulates in china's nation standard.ⅲIn the purification process. Firstly, we used active carbon for decoloring. The optimalcondition was at 55℃, for 90min, the dosage of carbon is 0.5%. The decoloring ratereached 80%, the losing rate of pectin was less than 10%. But active carbon can't beremoved easily. Secondly, we studied the effect of H2O2 on decoloring, its decoloringrate reached 87.34%, but the losing rate of pectin also reached 40%, pectin lossed badly,and the gelling properties of pectin reduced greatly, thirdly, we decolored on pectinsolution with macroporons adsorption resin. The optimal technology parameters weregained: the best resin was X-5, temperature is 40℃, time 12h, decoloring rate 88%,losing rate less than 5%. On the base of static adsorption, we studied the impact ofdynamic adsorption decoloring. The conditions were: room temperature, pH value 2,flow rate 0.5mL/min. the decoloring rate was 81.26%, losing rate less than 4%, in theend we studied the rebirth of resin: room temperature, concentration of ethanol shouldbe 65%, ethanol solution should flow at 0.5mL/min to wash resin. In the end, thecarbohydrate can be removed about 96.35% with dialysis, the protein can be removedabout 61.49% by the method of trichloroacetic acid and the loss rate of pectin is only3.40%, then we got purified pectin solution.ⅳThe precipitation conditions were studies, the optimal technology parameters withethanol deposition method: ethanol condensation of 70%, precipitated several hours, atlast we got pectin product by filtrating. On the other hand, pectin solvent need not beingconcentrated, we can get pectin by salting out. The optimal technology parameters were:dosage of 10% Al2(SO4)3, pH 5, temperature 60℃, time is 60min. Then removed salt,the optimal conditions: removing salt solvent composed of 3% Hcl+60%anthol+37%H2O, dosage of 1.6 multiples, time 30min. The ethanol depositionmethod can get high quality pectin, but its cost is high, because it need large numbers ofethanol. Salting out leaved out the condensation procedure, saving time and cost, but itsproducts quality is low at gelling properties, color, ash and so on.ⅴPectin extracting solution crossed microfiltration membrane, the sequence ofMWCO was 0.3million→0.1million→30thousand→10thousand→5thousand, differentmolecular weight pectin was cut out. We analysed their characteristics. We found thatbig MW pectin had strong viscosity, so the gelling properties were also very strong.Pectin of 0.1-0.3 million MW accounts for 21.87%, pectin of＞0.3 million MWaccounts for 28.15%. In the infiltrated solution pectin only have 4.5%. Microfiltrationmembrane can cut out 95.5% pectin, the volume was, 0.1 multiple, so microfiltrationmembrane can be used to condensed pectin sparse solution. At the same time somesmall molecule impurity also be eliminated, the quality of pectin product surpass thoseformulates in china's nation standard. Its ash was less, gelling properities were strong.
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