*4.1.1 Solubility*

Solubility of legume protein is important in formulation of products such as plant based dairy alternative products and beverages among many other similar products. Protein possess minimum solubility at pH corresponding to their p1. This is because of a zero net charge at their pI which results in aggregation of proteins. In general, legume proteins have minimum solubility in the range pH 4–4.5, and solubility maxima at above pH 8 and below pH 2.5. There solubility is high at low and conditions, and high alkaline conditions. Solubility is lowest at the isoelectric points of proteins. This is taken advantage of during protein extraction when purifying proteins. Solubility of proteins is affected during processing depending on level of heat treatment. Protein of high solubility is achieved by mild processing conditions mainly in terms of heat treatment. Solubility of legume proteins generally vary with heat treatment and pH [43].
