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Hypoallergenic and Physicochemical Properties of the A2 β-Casein Fraction of Goat Milk
Korean J. Food Sci. An. 2017;37:940-947
Published online December 31, 2017
© 2017 Korean Society for Food Science of Animal Resources

Tae-Hwan Jung1, Hyo-Jeong Hwang2, Sung-Seob Yun3, Won-Jae Lee4, Jin-Wook Kim4, Ji-Yun Ahn5, Woo-Min Jeon6, and Kyoung-Sik Han2,6*

1Department of Health and Bio-Convergence, Sahmyook University, Seoul 01795, Korea
2Biomaterials Research Institute, Sahmyook University, Seoul 01795, Korea
3R&D Center, Edam Co. Ltd., Chungbuk 38755, Korea
4Department of Animal Bioscience and Institute of Agriculture and Life Science, Gyeongsang National University, Jinju 52828, Korea
5Division of Nutrition and Metabolism Research, Korea Food Research Institute, Wanju 55365, Korea
6Department of Animal Biotechnology and Resource, Sahmyook University, Seoul 01795, Korea
Correspondence to: Kyoung-Sik Han
Department of Animal Biotechnology and Resource, Sahmyook University, Seoul 01795, Korea
Tel: +82-2-3399-1765 Fax: +82-2-3399-1762 E-mail: kshan@syu.ac.kr
Received December 4, 2017; Accepted December 8, 2017.
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Abstract
Goat milk has a protein composition similar to that of breast milk and contains abundant nutrients, but its use in functional foods is rather limited in comparison to milk from other sources. The aim of this study was to prepare a goat A2 β-casein fraction with improved digestibility and hypoallergenic properties. We investigated the optimal conditions for the separation of A2 β-casein fraction from goat milk by pH adjustment to pH 4.4 and treating the casein suspension with calcium chloride (0.05 M for 1 h at 25°C). Selective reduction of β-lactoglobulin and αs-casein was confirmed using sodium dodecyl sulphate-polyacrylamide gel electrophoresis and reverse-phase high-performance liquid chromatography. The hypoallergenic property of A2 β-casein fraction was examined by measuring the release of histamine and tumor necrosis factor alpha from HMC-1 human mast cells exposed to different proteins, including A2 β-casein fraction. There was no significant difference in levels of both indicators between A2 β-casein treatment and the control (no protein treatment). The A2 β-casein fraction is abundant in essential amino acids, especially, branched-chain amino acids (leucine, valine, and isoleucine). The physicochemical properties of A2 β-casein fraction, including protein solubility and viscosity, are similar to those of bovine whole casein which is widely used as a protein source in various foods. Therefore, the goat A2 β-casein fraction may be useful as a food material with good digestibility and hypoallergenic properties for infants, the elderly, and people with metabolic disorders.
Keywords : goat A2 β-casein, αs-casein, β-lactoglobulin, hypoallergenic property, physicochemical property


February 2018, 38 (1)