Lupin protein: Isolation and techno-functional properties, a review

Plant proteins are rapidly becoming more of a prime interest to food manufactures as consumers are shifting away from meat-based diets. Therefore, food manufactures need to incorporate functional plant proteins as ingredients into their products. Lupin has a high protein (~40%) and fibre (~40%) content, is low in starch and gluten free hence, it can have an important role. Despite its nutritional and proven health benefits, lupin is underutilised and still does not play a major role in the human diet. Concentrating its protein and producing lupin protein isolate with suitable properties would make it attractive as a high protein and functional ingredient for food manufacturing. Over the recent years the industry has shown interest in large scale production of lupin protein isolate and improving its techno-functional properties. This paper reviews the literature on different lupin protein isolation techniques and conditions. The impact of protein isolation technique on chemical composition, yield and physiochemical properties including solubility, water holding capacity, molecular weight and particle size distribution, of the resultant protein isolates, are compared and contrasted. Moreover, major functional properties such as viscosity, gelling, emulsification, and thermal properties of the isolated proteins are reviewed. Varied extraction yields and largely different properties and functionalities are achieved for different lupin protein extraction techniques. In the light of the unique composition and nutritional properties of lupin seed and its protein component, future research for improving the protein isolation process for lupin and improving its physical functionalities using innovative technologies are discussed.