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 ºC for 20 min 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 ºC for 20 min.

The improvements on aluminosilicates dissolution through microwave-assisted acid decomposition procedures for Na and Al quantification by inductively coupled plasma optical emission spectrometry (ICP OES) are reported here. Complete dissolution of the samples is achieved employing 4 mL of HNO3 and 3-4 mL of HF thus reducing the total amount of these reactants in comparison with procedures found in the literature. Additionally, the type of crucibles used in the calcination for sample preparation step is also evaluated. Na and Al concentrations are in agreement with the expected values on the samples. Estimated silicon amount is achieved by difference of sodium and aluminum, and then Si/Al molar ratios were calculated for samples calcined in both porcelain (Si/Al is in the range 22-42) and platinum (Si/Al is in the range 27-40) crucibles, showing no difference between these procedures.

A composição de ácidos graxos de seis amostras de Orbignya phalerata de diferentes cidades do estado do Maranhão foi estudada. Os óleos foram extraídos utilizando extrator Soxhlet por duas metodologias e a composição de ácidos graxos foi avaliada por cromatografia gasosa-espectrometria de massas (CG-EM). O teor da fração de lipídios revelou que o solvente usado influencia na extração, sendo a maior porcentagem obtida com hexano. O teor de lipídios variou de 62,46-67,45%, com predominância de ácidos graxos saturados (80,32-87,80%), principalmente ácido láurico (C12:0) com percentual de 44,86-52,15%. A análise multivariada mostrou a distribuição das amostras de O. phalerata em três regiões distintas e sugere que a composição química dos óleos pode estar associada com a sua localização geográfica. Estes dados mostram o conhecimento da biodiversidade de ácidos graxos de O. phalerata entre as diferentes regiões do estado do Maranhão.

The fatty acid composition of six Orbignya phalerata samples of different cities from Maranhão State (Brazil) was studied. The oils were extracted by two methods using Soxhlet extractor and the fatty acid composition was evaluated by gas chromatography-mass spectrometry (GC-MS) analysis. The lipid fraction content showed that the solvent used influences lipid extraction, the highest percent was obtained with hexane. Lipid content ranged from 62.46-67.45%, with predominance of saturated fatty acids (80.32-87.80%), mainly lauric acid (C12:0) with 44.86 to 52.15%. Multivariate analysis showed the distribution of O. phalerata samples into three distinct regions and suggests that the oil chemical composition may be associated with their geographic location. These data show knowledge of the biodiversity of O. phalerata fatty acids among the different regions of the Maranhão State (Brazil).