Improving Laccase Catalyzed Cross-Linking of Whey Protein Isolate and Their Application as Emulsifiers

• Published in: Journal of agricultural and food chemistry 2011-02, Vol.59 (4), p.1406-1414
• Main Authors: Ma, Hairan, Forssell, Pirkko, Partanen, Riitta, Buchert, Johanna, Boer, Harry
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cross-Linking Reagents - metabolism; Emulsifying Agents - chemistry; Emulsions - chemistry; Food additives; Food Chemistry/Biochemistry; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; Laccase - metabolism; Linseed Oil; Milk and cheese industries. Ice creams; Milk Proteins - chemistry; Milk Proteins - metabolism; Particle Size; Vanillic Acid - chemistry; Water; Whey Proteins
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf103591p

Whey protein isolate (WPI) was chemically modified by vanillic acid in order to enhance its cross-linkability by laccase enzyme. Incorporation of methoxyphenol groups created reactive sites for laccase on the surface of the protein and improved the efficiency of cross-linking. The vanillic acid modified WPI (Van-WPI) was characterized using MALDI-TOF mass spectrometry, and the laccase-catalyzed cross-linking of Van-WPI was studied. Furthermore, the vanillic acid modification was compared with the conventional approach to improve laccase-catalyzed cross-linking by adding free phenolic compounds. A small extent of the vanillic acid modification significantly improved the cross-linkability of the protein and made it possible to avoid color formation in a system that is free of small phenolic compounds. Moreover, the potential application of Van-WPI as emulsifier and the effect of cross-linking on the stability of Van-WPI emulsion were investigated. The post-emulsification cross-linking by laccase was proven to enhance the storage stability of Van-WPI emulsion.