Enzymatic and chemical modification of zein for food application

Background: Plant-based proteins are in the focus of food science research, partly in response to consumers' growing interest in a more economical and environmentally sustainable diet, as well as the rise in veganism and vegetarianism in Western cultures. Although zein, the major corn protein, is a promising protein source for food applications, it lacks important functional properties that could expand its utilization. Thus, zein functionalization is warranted and is studied in different research fields. Scope and approach: This review provides an overview of the possible advantages of enzymatic and chemical modifications of zein and reports current and future applications of this chemistry in processing of zein in various food applications. The protein-modifying enzymes used for zein functionalization for different food applications in last three decades are discussed, along with the mechanisms of action such as crosslinking, deamidation, glycosylation and hydrolysis. Use of natural compounds or safe chemical methods for zein functionalization for possible food applications are also reviewed, including chemical crosslinking and deamidation. Key findings and conclusions: The enzymatic and chemical alteration of zein, such as crosslinking, deamidation and hydrolysis, may be very useful tools for modifying the functionality of zein for a wide range of food applications. Thus, developing understanding of the relationship between functional properties of modified zein and the degree of modification could directly translate to increased incorporation of higher quality zein-based food products.