Lentil protein: a review of functional properties and food application. An overview of lentil protein functionality

There is an increased interest, driven by environmental sustainability and food security points of view, in seeking new protein sources as alternatives to replace animal proteins (Day, Trends in Food Science and Technology, 32, 2016, 25). Pulse proteins, including lentil proteins (LP), are promising good substitutes as the wide variety of functional properties shown by them (Alsohaimy etal., World Journal of Agricultural Sciences, 3, 2007, 123; Boye etal., Food Research International, 43, 2010a, 537). Interest in LP has grown due to its high nutritional value, good Leu/Ile and Leu/Lys ratios (1.24-1.98 and 1.08-2.03, respectively) (Urbano etal., Lentil: An Ancient Crop for Modern Times, 2007, 47, Berlin: Springer), high digestibility (similar to 83%) (Barbana & Boye, Food & Function, 4, 2013, 310), and its potential use in food product applications (Farooq & Boye, Novel Food and Industrial Applications of Pulse Flours and Fractions. Pulse Foods, 1st edn, 2011, Amsterdam: Elsevier Ltd; Aider etal., Journal of Food Research, 1, 2012, 160; De la Hera etal., LWT - Food Science and Technology, 49, 2012, 48; Turfani etal., LWT - Food Science and Technology, 78, 2017, 361). On the other hand, great progress has been made lately to reveal the good functionality of LP such as solubility and emulsifying, foaming and gelation capacities (Avramenko etal., Food Research International, 81, 2016, 17; Jarpa-Parra etal., Food Hydrocolloids, 61, 2016, 903; Primozic etal., Food Chemistry, 237, 2017, 65). However, the relatively unknown relationship between its molecular structure and functionalities and the lack of knowledge of the impact of the extraction and environmental conditions on those properties has hindered the exploitation of their full potential. This review describes the current knowledge of the LP structure, physical chemistry and functional properties, and its potential role as an ingredient for the development of food grade products. The gap between the current knowledge and what remains to be known is emphasised.