酶解咸鸭蛋蛋清制取白蛋白肽的研究

【作者】 杜永盛；

【导师】 冯凤琴；

【作者基本信息】 浙江大学 ， 食品科学， 2006， 硕士

【摘要】 生物活性肽由于其高效的营养价值,功能活性,是目前营养界研究得比较多的一个热门课题,而咸鸭蛋蛋清作为食品工业生产中的废弃物虽然含有较多的优质蛋白质,却因其盐分含量较高而无法利用遭到丢弃。 本论文研究以本身利用价值不大的咸鸭蛋蛋清为原料,经过选择高效率的蛋白酶水解,制取分子量小于5000的富含白蛋白肽的生物活性肽产品,并利用膜过滤技术去除原有的以及水解过程中增加的盐分,使得产品中的盐含量大大降低,符合人体食用的要求。 本文首先研究了咸鸭蛋蛋清制取白蛋白肽的工艺及工艺优化。工艺优化的重点是酶解反应条件的优化。通过对酶种类、底物浓度、酶浓度、酶解体系的pH、酶解温度和酶解时间等进行单因素试验,以及随后的正交试验综合分析,得到了酶解反应的最佳条件:选用酸性蛋白酶、稀释倍数为1、酶用量为3000U/g、pH为2.5、反应温度为45℃、酶解时间为6h。 接着,本文又研究了脱盐方法的选择。根据对原料脱盐和水解以后对水解液脱盐的优缺点的分析,选择采用膜过滤技术对原料或水解液进行脱盐试验。利用超滤技术对咸鸭蛋蛋清直接脱盐,选用截留分子量为10000的超滤膜可使脱盐率达到83.81%,蛋白质截留率达到86.1%。利用纳滤技术和电渗析技术对水解液进行脱盐,当pH3.2时用NF-90的纳滤膜使脱盐率达到94.3%,蛋白质截留率达到84.27%。在pH4.2时利用电渗析使脱盐率达到96.69%,蛋白质截留率达到71.4%。更多还原

【Abstract】 Bioactive peptide has a high nutrition of value and more functional activities. So it is a popular subject in nutrition now. The egg white of salted duck eggs contains abundance of high quality protein, but it can’t be used directly, and is commonly discarded because of its high salt content. That induced serious environment problem and great waste of the high quality protein.This paper researched on the bioactive peptides made from salted duck eggs white which was rich of ovalbumin and was of little commercial value through hydrolyzing by proteases and subsequent membrane filtration to get rid of the extra salt so that the final product could be more useful for human and animals.Firstly, the technology of making ovalbumin peptides was optimized. The enzymatic reaction conditions such as enzyme species, substrate concentration, enzyme concentration, pH, temperature and time of reaction was studied. The optimal conditions of enzymatic treatment was obtained as follows: chose acid proteinase, dilution rate was 1, dosage of enzyme was 3000U/g, pH was 2.5, temperature was 45 ℃, and raction for 6hours.Then the desalting method of the final hydrolyzed product was compared and chosen. The advantage and disadvantage of desalting to the egg white and desalting to the hydrolyzed egg white were evaluated. The membrane filtration technology was chosen to be used for desalting. The results showed that ultra filtration by the molecular mass cutoff 10000 was suitable for egg white, the desalinization rate was 83.81%, and the protein retention was 86.1%. And the nanofiltration and electro dialysis were suitable for hydrolyzed product, the desalinization rate and protein retention of nanofiltration could reach 94.3% and 84.27% using NF-90 at pH=3.2. The desalinization rate and protein retention of electro dialysis could reach 96.69% and 71.4% at pH=4.2.更多还原