An automated high-throughput approach for determining protein solubility of commercial plant protein concentrates and isolates

Understanding the solubility of plant-based proteins is essential for advancing their research and food applications. This study introduces an innovative high-throughput method designed to determine protein solubility in a variety of commercial plant protein ingredients. The sample preparation and analysis steps were miniaturized in multi-well plates and automated with a liquid handler. This method greatly increased the efficiency for solubility determination as it allows 96 samples to be prepared and analyzed simultaneously. This platform was then leveraged to assess the accuracy of estimating protein solubility in commercial plant protein ingredients, including those derived from milk (as a reference), soy, pea, faba bean, and canola. As a shortlisted method for the high-throughput setup, bicinchoninic acid (BCA) assay was evaluated for its accuracy of estimating protein concentration in commercial plant protein ingredients. The proposed method showed good agreement with the reference Kjeldahl method, with R 2 = 0.90 and consistent results across a range of commercial plant protein samples. The precision of the proposed method was satisfactory with a coefficient of variation of less than 15%. The proposed miniaturized high-throughput workflow would be a valuable tool to screen protein solubility for plant protein research and food applications in a rapid and reliable way.