Epsilon Archive for Student Projects

Abstract

Egg protein is used in a variety of food products due to its excellent functional properties (solubility, emulsification, foaming and gelling) and protein quality. Concerns about high cholesterol, allergies, animal welfare, high food costs, as well as the food productions negative impact on the environment has led to an increased interest in alternative protein sources that can act as egg replacers in food.

This literature study has the aim to compare the functional properties and protein quality of soy and pea with egg, this in order to evaluate their potential as egg replacers in traditional egg foods without dairy or animal ingredients. The findings showed that soy and pea protein possess similar solubility pattern as egg protein. Soy and pea protein have emulsifying properties that are similar to egg protein and changing the pH can regulate the thickness of the emulsion. Both soy and pea protein are able to form foams but pea protein is shown to be a better foaming agent than soy protein. Egg protein form stronger foams in room temperature than the two legume proteins. The gelling properties were shown to be best for egg and soy protein, but soy proteins do not form proper gels at higher temperatures and are not suitable for heat- induced food gels. Pea proteins form weak gels and are not applicable for food gels.

The drawbacks with using legume proteins as egg replacers are their content of anti-nutritional substances as well as their limitation in some sulfur containing amino acids, which affect the protein quality in a negative way. The protein quality for egg, soy and pea protein was evaluated by comparing the results from different scoring methods (e.g. PDCAAS) aimed for this. Through this evaluation, soy protein was found to be a complete protein. Pea protein was shown to be an incomplete protein, but can be complete if mutual supplementation is applied.

The study also showed that foods based on soy and pea protein do not have the same texture, color or odor as food products based on egg protein, and that the consumer acceptance for this kind of products is low. Further studies have to be carried out on optimization of formulas for legume-based products in order for them to gain consumer acceptance and succeed on the market.