Casein hydrolysis by Bifidobacterium longum KACC91563 and antioxidant activities of peptides derived therefrom

Abstract

Milk protein is a well-known precursor protein for the generation of bioactive peptides using lactic acid bacteria. This study investigated the antioxidant activity of bovine casein hydrolysate after fermentation with Bifidobacterium longum KACC91563 using the 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assay and total phenolic content (TPC). The antioxidant activities of the 24-h and 48-h hydrolysates were higher than that of the 4-h hydrolysate (2,045.5 and 1,629.3 μM gallic acid equivalents, respectively, vs. 40.3 μM) in the ABTS assay. In contrast, TPC values showed activities of 43.2 and 52.4 μM gallic acid equivalents for the 4-h and 24-h hydrolysates, respectively. Three fractions (≥10 kDa, ≥3 but <10 kDa, and <3 kDa) were separated from the 24-h hydrolysate by ultrafiltration. Among these fractions, the <3 kDa fraction exhibited the highest antioxidant activity (936.7 μM) compared with the other fractions (42.1 and 34.2 μM for >10 kDa and 3-10 kDa fractions, respectively). Through liquid chromatography-electrospray ionization-tandem mass spectrometry analysis, 2 peptides, VLSLSQSKVLPVPQK and VLSLSQSKVLPVPQKAVPYPQRDMPIQA, containing the fragment VLPVPQ that has antioxidant properties, were identified in the <3kDa fraction after 24h of hydrolysis. The present study demonstrates the possibility of antioxidant peptide production from bovine casein using Bifidobacterium longum.

Antioxidant Activity of Porcine Skin Gelatin Hydrolyzed by Pepsin and Pancreatin

“…Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) was performed as previously described by Chang et al (2013b), using a 5% acrylamide stacking gel and 15% acrylamide separating gel. After migration, the gel was stained and destained by previously described method (Chang et al, 2012) Gelatin hydrolysis Gelatin was provided by Geltech Co. Ltd, (Korea) and directly utilized for hydrolysis by gastrointestinal enzymes such as pepsin and pancreatin.…”

Identification and Characterization of a Novel Antioxidant Peptide from Bovine Skim Milk Fermented by Lactococcus lactis SL6

“…2) following the methods previously described by Chang et al (2013). The samples were analyzed in a Triple TOF 5600 Q-TOF LC/MS/MS system (ABSciex, CA) using a Ultimate 3000 RSLC HPLC system (Thermo Fisher Scientific Inc., USA), including a degasser, an auto-sampler, diode array detector and a binary pump.…”

“…The antioxidant activity of the sample was measured as free radical scavenging activity of ABTS and 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical cation according to the previously described method by Chang et al (2013) and Volta et al (2014) with minor modifications.…”

“…In addition, milk fermentation by lactic acid bacteria releases a large number of peptides with various biological functions, such as antioxidant (Chang et al , 2013), angiotensin-converting enzyme inhibitory (Ha et al , 2015), immunomodulatory (Gauthier et al , 2006), opioid activities (Park, 2009). …”

“…Suetsuna et al (2002) and Lopez-Exposito et al (2006) also reported antioxidative peptides from the peptic digests of α s1 - and κ-casein, respectively. Recently, Chang et al (2013) identified two antioxidative peptides from the bovine β-casein hydrolysate fermented by Bifidobacterium longum . However, to date, only a few antioxidant peptides from fermented milk products have been identified and characterized.…”