Sample Preparation Applied to Analysis of Proteins in Cowpea Seeds (Vigna unguiculata (L.) Walp.)

Thábata Nascimento, Tiago Coelho, Cícero Lopes Júnior, Samuel Sousa, Herbert Barbosa
2018 Journal of the Brazilian Chemical Society  
In this study, 20 different protocols for protein extraction of cowpea seeds in natura were evaluated taking into account four parameters: cell disruption method, time, temperature and solvent. Factorial design experiments were executed to determine the effects on the total protein content of extracts. The total protein content was determined and the results were in the range of 8.75 ± 1.3 and 86.6 ± 6.9 mg g -1 . The richest protein extracts were obtained using Tris-HCl buffer at 50 °C for 20
more » ... in for each assessed cell disruption method. However, the results using water were similar to buffer according to t-test at the 95% confidence level. Six protocols demonstrated higher extraction efficiency. Comparative proteomic study using size exclusion chromatography coupled to diode array detector (SEC-DAD) revealed that the one protocol extracted simultaneously high and low molecular mass biomolecules. In fact, the effect of microwave radiation promoted an increased solubility of biomolecules in water. The analysis of chromatographic profiles for principal component analysis (PCA) highlights the greater efficiency of extraction with the application of this protocol. Therefore, our study showed that the optimum condition for extraction of cowpea seed protein consists of water assisted by microwave radiation at 50 °C for 20 min. P2 deionized water, 25 °C, 20 min, manual maceration P3 deionized water, 50 °C, 10 min, manual maceration P4 deionized water, 50 °C, 20 min, manual maceration P5 buffer, 25 °C, 10 min, manual maceration P6 buffer, 25 °C, 20 min, manual maceration P7 buffer, 50 °C, 10 min, manual maceration P8 buffer, 50 °C, 20 min, manual maceration P9 deionized water, 25 °C, 10 min, sonication P10 deionized water, 25 °C, 20 min, sonication P11 deionized water, 50 °C, 10 min, sonication P12 deionized water, 50 °C, 20 min, sonication P13 buffer, 25 °C, 10 min, sonication P14 buffer, 25 °C, 20 min, sonication P15 buffer, 50 °C, 10 min, sonication P16 buffer, 50 °C, 20 min, sonication P17 deionized water, 50 °C, 10 min, microwave radiation P18 deionized water, 50 °C, 20 min, microwave radiation P19 buffer, 50 °C, 10 min, microwave radiation P20 buffer, 50 °C, 20 min, microwave radiation Sample Preparation Applied to Analysis of Proteins in Cowpea Seeds (Vigna unguiculata (L.) Walp.) J. Braz. Chem. Soc. 142
doi:10.21577/0103-5053.20180163 fatcat:ekvadjw3dbafraox3kmdyx4fey