Composition and functional properties of saline-soluble protein concentrates prepared from four common dry beans (Phaseolus vulgaris L.)

Authors: Hojilla-Evangelista, Milagros - Mila; SUTIVISEDSAK, NONGNUCH - Ag Precision Formulators, Llc; Evangelista, Roque; Cheng, Huai; Biswas, Atanu

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/17/2018
Publication Date: 8/15/2018
Citation: Hojilla-Evangelista, M.P., Sutivisedsak, N., Evangelista, R.L., Cheng, H.N., Biswas, A. 2018. Composition and functional properties of saline-soluble protein concentrates prepared from four common dry beans (Phaseolus vulgaris L.). Journal of the American Oil Chemists' Society. 95:1001-1012. doi: 10.1002/aocs.12135.
DOI: https://doi.org/10.1002/aocs.12135

Interpretive Summary: In this research, we produced a high-protein product from common dry beans with nutritional and functional properties that are desirable for food and non-food systems. Developing new uses and markets for dry bean protein will expand the utilization of 2.3 billion lbs of dry beans produced mainly for food in the U.S. and certainly generate additional income for our dry bean growers. In the current work, we extracted proteins from four common beans (black, dark red kidney, great northern, and pinto) by using warm saline solution and produced spray-dried extracts with high purity (~80%) protein concentrates. We found that the bean protein concentrates contained notable amounts of nutritionally essential amino acids, as well as those with reactive groups that can participate in various chemical reactions. We observed that all our bean protein concentrates were highly soluble in very acidic (pH 2), neutral (pH 7) and highly alkaline (pH 10) aqueous solutions. Thus, three protein classes could be used in many food systems and non-food applications (e.g., adhesives, which are very alkaline). We found all our bean protein samples to have excellent foaming capacities and stabilities. We also found that both bean meal proteins and bean protein concentrates had exceptionally high emulsifying capacities and formed the most stable emulsions when they were dispersed in alkaline aqueous solutions. The functional properties of our bean proteins indicate that they may find practical uses in health foods, nutritional supplements, acidic beverages, pressurized foamed or whipped products, and emulsions, such as salad dressings or paints. Our research provided fundamental data for most viable applications for the bean protein concentrate and will be of interest to R & D scientists, food technologists and polymer chemists.

Technical Abstract: Chemical and functional properties of proteins from four common beans (Phaseolus vulgaris L.; black [BL}, dark red kidney [DRK], Great Northern [GN], and pinto [PT]) were determined to identify possible value-added uses. Proteins were extracted with 0.5 M NaCl at 45°C and analyzed for proximate and amino-acid compositions, molecular weights, and functional properties (solubility, foaming, emulsification, and water-holding capacity (WHC)). The lowest protein recovery was for BL bean (65%) and the highest for PT beans (77%). Protein extracts had 79-82% (dry basis [db]) crude protein. Ground beans (meals) and protein products had near- identical SDS-PAGE patterns of 10-12 polypeptide bands (MW = 6.5-107 kDa). Amino-acid profiles were also similar, with notable amounts of nutritionally essential amino acids. All bean-protein samples were least soluble (10–28% soluble proteins) at pH near 4.5 and highly soluble (50–94% soluble proteins) at pH 2, 7, and 10. Bean proteins exhibited excellent foaming capacities (> 110 mL) and stabilities (> 90% remaining foam after 15 min) regardless of pH. All bean-protein products had the highest emulsifying activity and stability indices at pH 10 (> 350 m2/g-1 protein and 44-142 min, respectively). WHC of proteins in bean meals were about two times higher than their protein extracts (2.3-3.4 and 0.9-2.0 g water per gram protein, respectively). GN, BL, PT, and DRK bean proteins have desirable properties that may find practical uses in health foods, acidic beverages, pressurized foamed products, and emulsions.