Aspects of structure and functionality in legumin and vicilin from vicia faba seeds

Abstract

Soy beans command a large proportion of the vegetable protein market of the food processing industry; however, their cultivation is limited by climatic factors. A crop able to compete in these markets, but suited to growth in cooler, temperate conditions would have political and economic advantages for Europe. One such crop under consideration is Vicia faba minor. A new faba bean line (IVS-G),developed by a breeding programme at Durham University, was compared to an established commercial variety (Maris Bead) for chemical, physical and functional characteristics. A selection of processing methods was used to produce proteinaceous materials equivalent to soy products already on the commercial market. The methods used were defatting, air-classification, and the production of isolates, proteinates and micellar protein preparations. The materials were assessed and compared to soy products for functionality in tests designed to assess solubility, gelling, foaming and emulsifying properties. The storage proteins, legumin and vicilin, are the major protein constituents of the bean seed, and their structural and functional properties were also investigated. The bean products had similar functional properties to equivalent soy products, when protein contents were also similar. However, the higher initial in vivo protein content of the soy bean does give the latter a competitive advantage. Also, the marketing of by-products of faba bean, eg. Starch and fibre, may prove difficult.