Legumes are valued worldwide as a sustainable and inexpensive meat alternative and are considered the second most important food source after cereals. Legumes are nutritionally valuable, providing proteins (20–45%) with essential amino acids, complex carbohydrates (±60%) and dietary fibre (5–37%). Legumes also have no cholesterol and are generally low in fat, with ±5% energy from fat, with the exception of peanuts (±45%), chickpeas (±15%) and soybeans (±47%) and provide essential minerals and vitamins. In addition to their nutritional superiority, legumes have also been ascribed economical, cultural, physiological and medicinal roles owing to their possession of beneficial bioactive compounds. Research has shown that most of the bioactive compounds in legumes possess antioxidant properties, which play a role in the prevention of some cancers, heart diseases, osteoporosis and other degenerative diseases. Because of their composition, legumes are attractive to health conscious consumers, celiac and diabetic patients as well as consumers concerned with weight management. The incorporation of legumes in diets, especially in developing countries, could play a major role in eradicating protein-energy malnutrition especially in developing Afro-Asian countries. Legumes could be a base for the development of many functional foods to promote human health.
Part of the book: Functional Food
There has been an increase in consumer demand for healthy food products made from natural ingredients. This demand has been partly addressed by the substitution of natural alternatives to synthetic ingredients. One such example in this endeavour, is the study of the application of natural biopolymers as food emulsion stabilisers. When biopolymers such as proteins and polysaccharides or their complexes are applied as emulsion stabilisers, they exhibit different modes of action. These include acting as emulsifiers (polypeptides), increasing the viscosity of the medium (polysaccharides), reducing coalescence by coating individual droplets as well as acting as weighting agents (polysaccharides and polypeptides). Biopolymers can be covalently complexed using chemical, enzymatic or thermal treatments. These treatments generally increase the robustness and solubility of the final complexes. Biopolymer complexes have been reported to show higher stability to varying temperatures, pH and ionic strength. When two incompatible biopolymers are mixed, either associative or segregative phase separation occurs. The former involves separation of oppositely charged polymers due to electrostatic repulsion and the latter involves separation of similarly charged or neutral biopolymers. In this chapter, the stabilising effect, complexation, mode of action, phase behaviour and future application of biopolymers in emulsions are discussed.
Part of the book: Science and Technology Behind Nanoemulsions