The use of plant proteins in the production of food for humans

Abstract

The increasing preference of vegetarian and vegan diets has led to the development of new and diverse food formulations based on plant proteins with high nutritive value. Industrial side-products such as functional potato proteins and non-functional corn zein fractions, along with pea proteins are promising sources of protein in food applications. The main goal of recent researches was to improve the functionality of zein, a by-product of the starch industry, and usage of potato protein along with pea protein by enzyme-mediated covalent crosslinking, and to enable its usage in food applications. It has been demonstrated for the first time the functionalization of zein in concentrated oil-in-water emulsions. Emulsions comprising 40% oil were fabricated using enzymatic crosslinking of potato protein or pea protein solubilized in the aqueous phase and zein solubilized in the oil phase. It has been shown that bacterial tyrosinase isolated and purified from Bacillus megaterium plays a crucial role in the gel-like structure formation of zein-potato protein or zein-pea protein stabilized emulsions. The tyrosinasecrosslinked emulsions were stable over a month without noticeable separation, compared to the non-crosslinked emulsions. The increase in stability is attributed to the formation of covalent bonds between potato and/or pea proteins and zein prtein fractions. Additionally, the presence of tyrosinase led to better stability, increased viscosity and paste like structure compared to zein-pea protein emulsion without tyrosinase. Zein and potato protein or pea protein complement each other in their amino acid composition and thus provide complete nutritional value to consumers. Enzymatic covalent bond formation in zein-pea protein or zein-potato protein complexes could be an important approach to design and tailor different vegan or vegetarian emulsion-based foods.