Effects of high pressure processing on the structural and functional properties of bovine lactoferrin

Abstract

Abstract High pressure processing (HPP) is an emerging non-thermal processing technology and highlights a vast prospect in the food industry. Bovine lactoferrin (LFb), a representative protein in nutraceutical supplement, was investigated by HPP in this study with focus on the changes in structural and functional properties. LFb was treated by HPP at different pH (4.0 and 6.0) and at 300–700 MPa for either 30 or 60 min. The results showed that the tertiary structure of LFb was significantly modified with increased intensity of HPP, indicating partial denaturation and aggregation of LFb. The decrease in the unordered structure indicated that HPP resulted in a looser secondary structure of LFb. HPP also improved the solubility, foaming and emulsifying properties of LFb, and the samples treated at 400 MPa for 30 min and 300 MPa for 60 min at pH 4.0, or 600 MPa for 30 min and 400 MPa for 60 min at pH 6.0, had the most enhanced functionality. Industrial relevance In recent years, high pressure processing (HPP) has been used in food industry as an alternative technology to improve functional properties of various kinds of proteins, including milk whey proteins such as β-lactoglobulin, α-lactabumin and bovine serum albumin, soy protein isolate, walnut protein isolate and so on. It was found that HPP produces a variable degree of protein denaturation, which leads to aggregation and dissociation of polypeptides, and modifies their surface hydrophobicity, solubility, and other physiochemical properties. Lactoferrin (LF) possesses a broad spectrum of functional properties towards humans and animals such as antimicrobial, anti-inflammatory, antitumoral and immunomodulatory activities. These functions make LF a valuable protein to industry. Thus, it is necessary to investigate the effect of HPP on the structure of LF under varying pH conditions. Furthermore, because the functional properties such as solubility, foaming and emulsifying properties of proteins are important to its application in food industry, the effect of HPP on these properties of LF was also been studied in this manuscript.