Purification and Identification of Antioxidant Alcalase-Derived Peptides from Sheep Plasma Proteins
Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Key Laboratory of Agro-Product Processing, Ministry of Agriculture and Rural Affairs, Beijing 100193, China
Institut de Tecnologia Agroalimentària (INTEA), Universitat de Girona, C/Maria Aurèlia Capmany 61, 17003 Girona, Spain
Authors to whom correspondence should be addressed.
Antioxidants 2019, 8(12), 592; https://doi.org/10.3390/antiox8120592
Received: 22 October 2019 / Revised: 18 November 2019 / Accepted: 25 November 2019 / Published: 27 November 2019
(This article belongs to the Section Natural and Synthetic Antioxidants)
In this study, sheep plasma was submitted to Alcalase-hydrolysis and peptides with better antioxidant properties measured through both the ferric-reducing antioxidant power (FRAP) and the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability assays were isolated and identified. After hydrolysate ultrafiltration and semi-preparative reverse-phase high-performance liquid chromatography, nine fractions (F1–F9) were obtained, with the two first (F1 and F2) showing the greatest antioxidant potential. These two fractions were further separated by the AKTA purifier system to generate four (F1-1–F1-4) and five (F2-1–F2-5) fractions, respectively, with two of them (F1-2 and F2-1) exhibiting appreciable FRAP activity and DPPH radical scavenging ability. Using liquid chromatography-tandem mass spectrometry, three antioxidant peptides were identified. From their amino acid sequences (QTALVELLK, SLHTLFGDELCK, and MPCTEDYLSLILNR), which include amino acids that have been previously reported as key contributors to the peptide antioxidant properties, it can be maintained that they come mainly from serum albumin. These results suggested that the sheep plasma protein can be considered as a good source of antioxidant peptides and bring forth new possibilities for the utilization of animal blood by-products.