| Natural pectin is existed in the form of fruit collagen in the plant that doesn't dissolved in the water. In the citrus peel the content of pectin is up to 10-30%, in the apple pomace is about 15%. The pectin is the natural component of human food at all times. It is allowed to use the pectin as food additives all around the world. It was used as gel,thickener, organizations forming agents, emulsifiers and stabilizers. In the medicine industry, pectin has a good effect on maintaining the natural content of cholesterin in the blood. It can prevent the poisoning of cation as a natural materials. China is a big county on planting apples, and the yield of apple is the number one in the world. The quantity of apples that used to processing syrup is very large and a large number of pomace was obtained. A majority of pomace was not be utilized effectively except a few are used as feed additive after airing. In order to provide the technology support of the pomace integrated utilization and pectin extraction, the research was focused on the key problems of pectin extraction. Compared with the traditional pectin extraction method, high intensity pulsed electric fields has a lot of advantages, such as low cost,short extracting time,low consuming energy and so on.Compared with the normal extracting method, PEF extracting technology was studied systemic in this paper. The special superiority of PEF was presented. At the same time pectin purification was carried out. The main conclusion is as follows:1. the effect of electric field intensity, pulse number, pH, stuff and liquid ratio and temperature on the extraction of pomace was studied by single factor analyse. The results are as follows:(1) The effect of electric field intensity on the yield of pectin was bigger under the conditions of velocity flow 16ml/min, pulse number 8, stuff and liquid ratio 1:20, pH 3, and temperature 55℃. With the increase of electric field intensity ,the yield of pectin increased at the earlier and then reduced. And the highest yield obtained when the electric field intensity reached 15KV/cm. So 15kV/cm was the optimum parameter for extracting pectin from pomace by PEF.(2) The effect of pulse number on the yield of pectin was bigger under the conditions of electric field intensity 15kV/cm, velocity flow 16ml/min, stuff and liquid ratio 1:20,pH 3, and temperature 55℃. With the increase of pulse number, the yield of pectin increased at the earlier and then reduced. And the highest yield obtained when the pulse number reacheed 10. So 10 was the optimum parameter for extracting pectin from pomace by PEF.(3) The effect of pH on the yield of pectin was bigger under the conditions of electric field intensity 15kV/cm, velocity flow 16ml/min, stuff and liquid ratio 1:20, and temperature 55℃. With the increase of pH, the yield of pectin increased at the earlier and then reduced. And the highest yield obtained when the pH reached 3. So 3 was the optimum parameter for extracting pectin from pomace by PEF.(4) The effect of stuff and liquid ratio on the yield of pectin was bigger under the conditions of electric field intensity 15kV/cm, pulse number 8, pH 3, velocity flow 16ml/min, and temperature 55℃. With the increase of stuff and liquid ratio, the yield of pectin increased at the earlier and then reduced. And the highest yield obtained when the stuff and liquid ratio reacheed 1:183. So 1:18 was the optimum parameter for extracting pectin from pomace by PEF.(5) The effect of temperature on the yield of pectin was bigger under the conditions of electric field intensity 15kV/cm, pulse number 8, velocity flow 16ml/min, pH 3, and stuff and liquid ratio1:18. The yield of pectin was increased at the rage of 30-60℃. It will be a little higher at 70℃than at 60℃, and the yield of pectin was decreased at when the temperature is 70℃and above. So 60℃was the optimum parameter for extracting pectin from pomace by PEF.2. The orthogonal test was carried out with reasonable level of electric field intensity,pH,pulse number,stuff and liquid ratio and temperature, the results are as follows:The electric field intensity,pH,pulse number,stuff and liquid ratio and temperature are the remarkable factors by PEF extraction pectin from pomace. And the electric field intensity was the most important factor, and the significant level was 0.01; Then it was followed by pulse number, with the significant level of 0.01; and pH was 0.05, stuff and liquid ratio was 0.05. The optimum parameter of electric field intensity,pH,pulse number,stuff and liquid ratio are determined by the orthogonal test, i.e.15kV/cm,3,10,1:19,60℃, and the yield of pectin was 14.12%.3. The effect of active carbon dosage,temperature,decolor time on the decolorization by Single factor experiment was studied. The result was: under the condition of the active carbon dosage 1.5g/100ml, temperature 60℃, and the decolorization time 20min, the transimittance of decolorization was 86.4%,and the yield of pectin was 12.7% 5.4. The removal of protein was about 60% by TCA method, and removal of sugar using dialysis was 90%.5. The orthogonal test was carried out with reasonable level of alcohol analysis temperature,the finall alcohol concentration,pH of alcohol solution and static time. The result was as follows: the optimum parameters were: the finall alcohol solution concentration 62%,pH 3.7,the static time 2.3h, and the temperature of alcohol solution 18℃, and the yield of pectin from pomace was 15.24%.6. The pectin that was extracted by PEF has the trait, such as the cementing was 126, loss on drying was 6.64%, total ash was 2.31%, the content of galacturonic acid was 78%, and the colour was light yellow. These indicators are all reach the quality standards of GBn246-85, FAO/WHO and FCC.7. The result of the yield of pectin was compared by PEF method, enzyme method, ultrasonic method,microwave method and ammonium oxalate method, the results were as follows:(1) The order of those five extraction methods that have been arranged by its yield of pectin: PEF method > ultrasonic method > microwave method > acid extraction > ammonium oxalate method.(2) The largest yield of pectin by PEF was 14.12%, while it was only 11.63% by ultrasonic method. So compared with the ultrasonic method, PEF method has the characteristics that the extraction time was short and it can deal with the sample continuously, at the same time, it was was economical and applicable.(3) The yield of pectin by PEF method was 1.37 times larger than the acid extraction method, 1.28 times larger than ultrasonic method, 1.4 times larger than ammonium oxalate method, and the extraction time was only several seconds. So compared with those methods, PEF has advantages on its extraction technics,extraction time and the yield of pectin.In a word, the optimum conditions and validation of extraction by PEF was studied. PEF has the advantages such as the higher extraction yield,short extraction time and the convenient operation. So it is a very promising method for plant bioactive components extraction.
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