Original title: Professor Bear Cub, University of Kentucky, USA: Animal and Plant Protein Oxidation: Chemical and Functional Meaning
Protein Oxidation is a complex chemical process that is widely present in food systems and can be caused by processing. This phenomenon was not well understood before, but it is now better understood. Early studies focused on the oxidation of muscle proteins, and later studies included plant proteins, milk proteins, and egg proteins. The protein oxidation process consists of free and non-free fundamentals, while the amino acid side chain group is usually the site of initial oxidant attack, producing protein carboxyl, desulphide, tyrosine, and protein free fundamentals. With changes in protein structure and the formation of protein polymers and aggregates, significant changes in solubility and functionality, such as geling, emulsification, foaming and water preservation, can result. The oxidant dose dependence effect has been widely reported, i.e. mild to moderate oxidation enhances functionality, while strong oxidation leads to insoluble and functional loss.
, the degree of protein oxidation in animal and plant protein foods has been widely concerned in model systems and in-place studies through oxidation and antioxidant strategies. In this paper, Youling L. Xiong and Anqi Guo of the Department of Animal and Food Sciences at the University of Kentucky School of Agriculture review the history of protein oxidation research in food, and review the effects of chemical and enzyme-based oxidation on the functional properties of proteins in meat, legumes, grains, dairy products, and eggs, based on literature published in recent decades.
protein oxidation is a little
-known phenomenon compared to lipid oxidation, which is common in food preparation, processing and storage. Reactive oxygen (e.g. OH and RO), many lipid oxidation sub-productions, and Strecker's degradation of carboxy and ketones are the main triggers for protein oxidation. Oxidation modification and structural changes in the amino acid side chain group (secondary and third levels) cause the accumulation and production of functional or non-functional protein particles. The former is usually soluble and can be produced under mild oxidation conditions, while the latter occurs when protein concentrations are high or when widely modified during prolonged exposure to oxidants. The use of appropriate natural chemical modifiers can improve its gel, emulsification, foaming, film-forming, water preservation and enhance its texture properties. Versatile food additives, such as astrophic acids and phenolic acids, are particularly attractive because they modify both proteins and inhibit poor lipid oxidation. Oxidases, including glucose oxidases and lipooxygenases, are also promising candidates due to their gentle effects and progressive catalytic effects on ROS.
study points out that it is necessary to explore the optimal oxidation modification levels using different ingredients and processing strategies to ensure consistent results between batches and that product flavor is not affected. In order to provide nutritional balance and economically stimulating dietary choices, pre-made conditioning foods are mixed with more and more different proteins. Although surface and structural characteristics determine the instability of proteins for oxidation modification, the preferred target peptide species in protein mixtures (e.g., plant protein-based meat similars) may change, depending on pH, salt concentration, temperature, and other processing parameters that change the structure. This is one of the areas where ongoing research is needed to fill the knowledge gap. Finally, while mild oxidation may not have a significant impact on the nutritional quality of protein foods (since, according to most published reports, loss of essential amino acids and reduced protein digestion tend to occur to a limited extent), safety aspects associated with oxidation at all levels should be carefully studied.
Senior Professor of Animal and Food Sciences, University of Kentucky School of Agriculture
Director of Research, Department of Animal and Food Sciences, University of Kentucky
Journal of Muscle Foods Associate Editor
Food Bioscience Associate Editor
Bear Cub, Senior Professor, Department of Animal and Food Sciences, University of Kentucky, Director of Research, Research Center for Nutritional Sciences, University of Kentucky, and former Chair of the IFT Meat Science Branch. Professor Xiong's research mainly focuses on food protein chemistry and function, meat processing technology and safety, polyphenol antioxidants, antioxidant peptides and protein oxidation, and promotes scientific research results for industrial applications. A total of more than 280 SCI articles have been published, more than 130 speeches have been made at international academic conferences, and more than 40 international academic conferences have been organized.
Xiong's enduring contribution to food science and technology has been widely recognized in academia and industry. He has received the Outstanding Achievement Award (1995), the American Chemical Society Young Scientist Award (1997), the American Meat Science Association Outstanding Research Award (1999), the University of Kentucky Outstanding Research Award (2009), and the Outstanding Graduate Mentor Award. (2011) and the Professor of Excellence Award (2011), and were elected to the American Food Science Association (IFT), the Agricultural Food Chemistry Department (ACS AGFD) of the American Chemical Society and the International Academy of Food Sciences (IAFoST) in 2010, 2012 and 2016, respectively.
Particularly noteworthy is that Professor Xiong was awarded the Bertebos Prize, the highest prize of the Royal Swedish Academy of Agricultural and Foran sciences, in January 2015 and is the only Chinese scientist to have received this award to date. Professor Xiong is a former scientific editor of the SCI journal Journal of Food Science and associate editor of Journal of Muscle Foods. He currently serves as Deputy Editor-in-Chief of SCI Journal Food Bioscience, reviewer or editorial board member of more than 40 international food science and nutrition journals, and judge of many U.S. and other countries, including the China Research Fund.
article "Animal and Plant Protein Oxidation: Chemical and Functional Property Significance" was published online at Foods.