Evaluation of Functional Properties and the Lipase Inhibitory Activity of Proteins from Amaranthus cruentus Seeds

Obesity is characterized by excessive body fat and is a chronic and complex disease. The medications used to date for the treatment of obesity have exhibited various side effects. Thus, new substances must be sought from alternative sources as antiobesity drugs. Recently, there has been increased interest in the study of bioactive peptides generated from plant proteins for functional food development. Plant proteins have exhibited pancreatic lipase inhibitory activity and can be potentially studied as sources of anti-obesity drugs for long-term use. Amaranthus cruentus seeds are very nutritious, with high protein content and medicinal properties. Hence, this study focuses on pancreatic lipase inhibitory activity and functional properties of Amaranthus cruentus seed protein isolates.

Proteins were isolated using conventional and thermal isoelectric precipitation methods. The protein's ability to inhibit lipases was assessed using both synthetic and natural substrates. The functional properties, such as nitrogen solubility, foaming test, emulsification test, and water and oil holding abilities, were evaluated. The protein isolates were characterized by SDS-PAGE and DSC. Cell line studies were performed on 3T3-L1 cell lines to determine the cytotoxicity and anti-adipogenic activity of protein isolates.

Proteins 1, 2, 3, and 4 were found to have high protein yield and protein content. SDS-PAGE characterization showed protein bands at different molecular weights (kDa). Protein isolates demonstrated good fun ctional properties and antilipase activity as compared to flour. In the cell line experiments, protein 1 exhibited a dose-dependent reduction in the lipid content.

A. cruentus seed protein could pave the way for the development of nutraceutical formulation in the treatment of obesity.