A Two-Step, One-Pot Enzymatic Method for Preparation of Duck Egg White Protein Hydrolysates with High Antioxidant Activity

Abstract

Biocatalytic hydrolysis reactions were designed for preparation of bioactive hydrolysate of duck egg white protein (DEWP) employing two enzymes in one pot. Firstly, the fresh DEWP was thermal treated at 95 °C, for 40 min at pH 10, to effectively deactivate enzyme inhibitors thus facilitating the following two-step enzymatic hydrolysis. Compared with single-enzyme processes, the two-step enzymatic procedures showed much higher reaction efficiency. The first enzymatic step (in the presence of Alcalase or hydrolase SEEP) allowed to hydrolyze DEWP with degree of hydrolysis (DH) of 8.8-10% and soluble peptide yield (SEP) of 60.5-70.2% in a short period (4 h). The second enzymatic step (in the presence of Trypsin or Alcalase) gave a further degradation of DEWP with DH and SEP being more than 26.2% and 90.4%, respectively. The final hydrolysates exhibited high antioxidant activity in an evident DH dependent manner. The hydrolysates achieved by sequential addition of the proteinase SEEP and Alcalase at DH value 21% gave the highest antioxidant activity, which was mainly ascribed to the changes in the amino acid compositions that the contents of some key amino acids and total hydrophobic amino acids were significantly improved by the enzymatic hydrolysis.

Production of Antioxidant Egg White Hydrolysates in a Continuous Stirred Tank Enzyme Reactor Coupled with Membrane Separation Unit

“…Alcalase is a commercial preparation of relatively crude bacterial extract comprising several proteases with different specificities (Kim et al 2007). The DH values presented here are significantly higher than those reported for the comparable reactions in a batch reactor, where DH of only 10.0 or 19.0 % was obtained after hydrolysis of EWPs by Alcalase for 3 and 4 h, respectively (Cigić and Zelenik-Blatnik 2004;Ren et al 2014). Higher hydrolysis efficiency obtained in current work could be explained by different reactor design used for the hydrolysis.…”

Overview of Antioxidant Peptides Derived from Marine Resources: The Sources, Characteristic, Purification, and Evaluation Methods

“…Numerous antioxidant peptides have been found from various terrestrial protein sources, such as proteins from milk [22], chicken muscle [23], eggs [3], and seeds of plants [24]. The composition and primary sequences of amino acids of marine proteins are different from those of terrestrial proteins.…”

“…Therefore, efforts to search for new sources of natural proteins may not only lead to new kinds of bioactive peptide, but also contribute to a better understanding of the structures and antioxidant activities of the peptides [3]. Researchers also discovered that some antioxidant peptides also contain other bioactivity, such as anticancer [15], antihypertensive [16,17], and antimicrobial activity [18].…”

Purification and characterization of high antioxidant peptides from duck egg white protein hydrolysates

“…Therefore, it 54 was chosen to prepare peptides with high antioxidant activity and 55 additional value by enzymatic hydrolysis. Although the hydroly-56 sates from DEWP displayed high antioxidant activity [4], abundant 57 impurities and some low antioxidant peptides were included 58 excepted for meritorious peptides. The application of separation 59 and purification procedures was very essential to remove these 60 undesirable components for improving the bioactivity and 61 determining the composition of novel peptides expediently [5,6] Scavenging activity ð%Þ ¼ The reducing power was measured in terms of the absorbance 163 at 700 nm according to ''Siddhuraju'' method [9].…”