(P03-056-23) Effect of the Extraction Method on the Yield and Electrophoretic Profile of Proteins From Underutilized Mexican Legumes

Objectives: The aim of this study was to evaluate the effect of the extraction protocol on the yield and electrophoretic profile of proteins from the underutilized Mexican legumes guaje (Leucaena leucocephala), guamúchil (Pithecellobium dulce), and jinicuil (Inga jinicuil).

Methods: Seeds from guaje, guamúchil and jinicuil were analyzed for proximal content according to AOAC methods. Legume seeds were dried and ground to generate a flour. Legume flour was defatted with hexane, and three protein extraction methods were used: a) alkaline extraction individually, and alkaline extraction assisted by either b) ultrasound or c) microwave. Soluble proteins were quantified by the Bradford method. SDS polyacrilamide gel electrophoresis was used to determine the molecular weight of the extracted proteins.

Results: According to proximal analysis, protein content (in percentage) in the seeds were 23.6 for jinicuil, 26.8 for guamúchil, and 35.1 for guaje, being all results statistically different (p < 0.05). Regarding protein extraction yield, the best (p < 0.05) extraction method was that assisted by ultrasound, reaching a maximum of extraction percentage of 33.2 for jinicuil, 37.0 for guaje, and 40.7 for guamúchil. The lowest (p < 0.05) values for protein extraction yield in percentage was alkaline extraction individually (8.3 for jinicuil, 21.8 for guaje, and 26.8 for guamúchil). No changes (p > 0.05) in molecular weight or number of bands detected were found in the electrophoretic profile of the legume proteins extracted with different methods. However, ultrasound and microwave decreased the intensity of a 35 kDa, and a 41 kDa protein in guamúchil, as well as a 25 kDa protein in jinicuil.

Conclusions: From the legumes analyzed, guaje had the highest protein content. Ultrasound resulted the best method in order to obtain the highest protein extraction yield for the legumes used in this study, however, it was observed that it decreases the intensity of some protein bands, suggesting possible hydrolysis. Future studies will evaluate the impact of the extraction method on the physicochemical properties of proteins from underutilized Mexican legumes to generate ingredients with value added.

Funding Sources: This project is funded by a seed grant of The Institute for Obesity Research of the Tecnologico de Monterrey, Mexico.