鸭血球短肽的优化制备及其特性研究

Preparation and Characterization of Enzymatic Hydrolysis of Duck Blood Corpuscle Short Peptide

本试验旨在筛选水解效率高且脱色效果好的商业蛋白酶,建立血球短肽的优化工艺,比较其在酶解前后营养特性的变化,研究其功能特性与体外抗氧化能力,以研发功能性血球短肽产品,为家禽血液资源高值化的转化利用与深度挖掘提供理论依据与技术借鉴。比较酶种类、酶浓度、温度、p H、水解时间等因素对蛋白酶水解度(DH)、脱色程度、水解物产量的影响,采用正交试验设计优化血球短肽的最佳工艺,对血球短肽进行营养价值、功能特性及抗氧化性能评价。确定酸性蛋白酶为最佳水解酶,其水解鸭血球蛋白制备短肽的最优工艺参数为:酶用量6 000 U/g,温度50℃,p H 3.5,水解时间7.0 h。在此条件下,水解度为(25.10±0.65)%,水解物产量为(60.09±1.77)%。通过高效液相色谱分析水解产物分子质量分布。结果表明,酶解对血球蛋白有明显的降解作用,酶解产物主要以3 ku以下的短肽为主,其中1 ku以下占大部分(62.82%)。血球短肽粉呈乳白色,氨基酸种类齐全,必需氨基酸含量丰富(53.31%),鸭血球蛋白酶解后的溶解性大大提高(>60%),且具有良好的乳化稳定性。血球短肽清除自由基能力较强,随血球蛋白浓度的提升,清除1,1-二苯基-2-苦基肼自由基(DPPH·)与超氧阴离子能力随之愈强,还原力也逐渐增加。由此可见,酸性蛋白酶可有效水解鸭血球蛋白获得氨基酸含量丰富、溶解性好且具有抗氧化活性的乳白色血球短肽,可以作为功能性原料应用于食品与饲料中。

The aims of this study were to screen the commercial protease with high hydrolysis efficiency and good decolorization effect,and to establish process technology of blood corpuscle short peptide,compared the nutritional characteristics before and after enzymatic hydrolysis,to study its nutritional value,functional properties and antioxidant activity in vivo.The functional product of blood corpuscle short peptide was produced so as to offer theoretic basis and technical reference for the efficient conversion and utilization of poultry blood.Taking degree of hydrolysis（DH）,decoloration and hydrolysate yield as criterion,the effects of main parameters（such as types of protease,enzyme dosage,temperature,p H and hydrolysis time） and the optimal hydrolysis conditions were established based on the method of single-factor and orthogonal experiments.The blood corpuscle short peptide was used to study its nutritional,functional properties and antioxidant activity.W e selected the acidic protease as the best enzyme to hydrolyze protein in our experiments.The suitable conditions of enzymatic hydrolysis,i.e.enzyme dosage 6 000 U/g,hydrolysis temperature 50 ℃,p H 3.5,hydrolysis time 7.0 h,and the degree of hydrolysis was（25.10 ± 0.65） %,hydrolysate yield was（60.09 ± 1.77） % under the optimal conditions.The molecular weight distribution of the hydrolysate as determined by high performance liquid chromatography（HPLC） suggested that significant degradation of blood corpuscle proteins produced the hydrolysate mostly consisting of short peptides below3 ku with molecules less than 1 ku accounting for the majority（62.82 %） of the total peptides.The white blood corpuscle short peptide powder containing all the common amino acids was rich in essential amino acids（53.31 %） and had excellent solubility（ 60 %） and emulsifying stability.W ith the increasing concentration of blood corpuscle protein,its free radical scavenging activity [1,1-diphenyl-2-picrylhydrazyl radical 2,2-diphenyl-1-（2,4,6-trinitrophenyl） hydrazyl（DPPH ·）and superoxide anion]and reducing power increased.Therefore,acid protease serves best for the hydrolysis of duck blood corpuscle protein,and its peptide powder has good features with high protein,rich essential amino acids and strong antioxidant activity.The blood corpuscle short peptide can be utilized as functional material for the food and feed industry.