Purification and identification of five novel antioxidant peptides from goat milk casein hydrolysates

Abstract

The present research described the preparation, purification, and identification of antioxidant peptides from goat milk casein (GMC). Goat milk casein was hydrolyzed by using a combination of neutral and alkaline proteases to obtain goat milk casein hydrolysates (GMCH) with high antioxidant activity. After desalting by nonpolar macroporous absorption resin, GMCH was isolated and purified by gel filtration chromatography and reversed-phase HPLC, respectively, and further identified by nanoliter electrospray ionization-tandem mass spectrometry. Antioxidant activities of GMC, GMCH, and pure peptides were evaluated and compared using free radical scavenging activity, metal ion chelating ability, and anti-lipid peroxidation ability. Compared with GMC, the free radical-scavenging ability and ferrous ion-chelating ability of GMCH increased significantly. The inhibition effect of lipid peroxidation of GMCH was much stronger than that of tert-butylhydroquinone and phytogermine and a little lower than that of ascorbic acid. The antioxidant activity of GMCH could be attributed to the high antioxidant activity of oligopeptides, especially 5 novel oligopeptides: Val-Tyr-Pro-Phe, Phe-Gly-Gly-Met-Ala-His, Phe-Pro-Tyr-Cys-Ala-Pro, Tyr-Val-Pro-Glu-Pro-Phe, and Tyr-Pro-Pro-Tyr-Glu-Thr-Tyr, which were first observed in GMCH. The antioxidant activity of these 5 novel oligopeptides and GMCH increased 3.59 to 380 times compared with GMC, combining anti-lipid peroxidation ability of GMCH, which indicated that GMCH and its purified fractions in different stages could be used as functional food ingredients, food additives, and pharmaceutical agents in the future.

Iron (II)-chelating activity of buffalo αS-casein hydrolysed by corolase PP, alcalase and flavourzyme

“…Error bars are standard deviation from three replicates antioxidant activity and it affects other functions that contribute to the antioxidant activity. The stronger the metal chelating ability stronger, the stronger the antioxidant activity (Li et al 2013). Hence iron (II)-chelation activity of unhydrolyzed buffalo whole casein, their individual fractions and ultrafiltrate fractions (10 and 3 kDa) of α S -casein hydrolysates was evaluated.…”

“…Iron (II)-chelating power of casein hydrolysates also measures its free radical scavenging activity (Li and Zhao 2011). Li et al (2013) also found that stronger the metal chelating ability the stronger the antioxidant activity.…”

Structural and oxidative modifications, and antioxidant activity of β-lactoglobulin treated by ultraviolet light-C and ultrasound

“…The 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and2,2′-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid (ABTS) radical scavenging activity were estimated according to the previous methods [26] , with some modifications. DPPH: Briefly, a 0.8 mL (2 mg/mL) of β-Lg sample or ascorbic acid was added to DPPH solution (1.5 mL, 0.2 mM) freshly prepared in ethanol.…”

Perfil De Ácidos Graxos E Frações Proteicas Do Leite De Cabra

“…Tais pep tídeos bioativos exercem efeitos antitrom bóticos, anti-hipertensivos, antioxidantes, imunomoduladores, entre outros (MADUREIRA et al, 2007;PHELAN et al, 2009). Peptídeos bioativos foram identificados principalmente a partir de leite de vaca, mas também as proteínas do leite de ca bras incluem peptídeos com tais atividades (ATANASOVA; IVANOVA, 2010; ESPEJO-CARPIO et al, 2013;LI et al, 2013).…”