[Extraction and characterization of soluble protein fractions from Phaseolus lunatus L seeds]. / Extracción y caracterización de las fracciones proteínicas solubles del grano de Phaseolus lunatus L.

Legume proteins as a potential source of valuable nutrients, are the object of several studies in order to obtain the best use. A basic knowledge becomes more important for those proteins from species not wholly utilized, before using them as food ingredients. The objective of this work was to determine several structural and nutritional characteristics of the protein fractions from Phaseolus lunatus, separated in different solvents. The relative amount of extraction for the albumins (ALB), globulins (GLB), prolamines (PRL), and glutelins (GLT) was 62.3, 34.8, 1.4 and 1.5%, respectively. The SDS-PAGE electrophoretic profile of both ALB and GLB, showed seven common bands in intervals from 10 to 95 kDa, and 14 to 99 kDa, respectively; the amino acids profile showed that PRL was the rich fraction in sulfurated amino acids (11.5 g/100 g protein); the content of lysine in the fraction of ALB was smaller than expected but the requirement of the FAO in the fractions of GLB and GLT was covered. In general, the fraction of GLB had the best balance of amino acids and digestibility (80%); however, it had a relationship of calculated protein efficiency ratio (C-PER) of 0.11, smaller than the ratio in ALB (0.97). The calorimetric analysis showed denatured temperatures around 90 degrees C for the ALB, GLB, and GLU fractions. The PRL fraction probably did not present a thermal transition because the proteins were denaturalized by the extraction conditions.

Simultaneous spectrophotometric determination of phenilpropanolamine HCL, caffeine and diazepam in tablets.

A rapid, reliable and specific UV spectrophotometric method was developed to determine Phenilpropanolamine Hydrochloride (I), Caffeine (II) and Diazepam (III) formulated in tablets. This method was validated and compared with a liquid chromatography (LC) procedure used for the simultaneous quantitative analysis of the drugs. The established linearity ranges by both methods for compounds I, II and III were 0.36-0.88, 0.012-0.028 and 0.036-0.084 mg/ml, respectively. The correlation coefficients by HPLC were r(I)(2)=0.997, r(II)(2)=0.999, r(III)(2)=0.999 and by the UV spectrophotometric method were r(I)(2)=0.998, r(II)(2)=0.996, r(III)(2)=0.999. LC and UV methods showed excellent precision and accuracy. As regards precision, LC showed CV values range of 0.2-0.9 and UV 0.15-0.72. On the other hand, accuracy was obtained with CV values range of 0.1-1.8 and 0.32-1.11 for LC and UV, respectively. The recoveries of I, II and III were >98.04% for both methods over the linear range. The UV and HPLC methods have been successfully used to determine the I, II and III content in tablets of different origin.

Analysis of multicomponent formulations containing phenylpropanolamine hydrochloride, caffeine and diazepam by using LC.

A reverse phase high performance liquid chromatography assay was carried out for the simultaneous determination of three active principles present in tablets of different origin and wide commercial use in the Province of Córdoba (Argentina). Prescriptions, commercially available as appetite suppressants, very often include the active principles Phenylpropanolamine Hydrochloride (I), Caffeine (II) and Diazepam (III). Simultaneous determination of these three drugs: anorexic, central nervous stimulant and tranquilizer, respectively, in pharmaceutical dosage forms has not been reported. In this study these active principles are quantified. The only sample preparation necessary for the analysis was their dilution with acetonitrile. The resulting solution was filtered and analyzed on a column packed with Supelcosil LC-18 (5 microm) with acetonitrile:water (30:70 v/v) as initial mobile phase (0.4 ml min(-1)) and the detection was performed at 254 nm. Then a linear gradient up to 100% acetonitrile in 18 min (3.0 ml min(-1)) was applied. The procedure was simple and suitable for quality control. The calibration function was established in the ranges of 0.072-0.168 mg ml(-1) for I, 0.036-0.084 mg ml(-1) for II and 0.06-0.196 mg ml(-1) for III. The detection limits of these compounds were 12.8, 4.1 and 11.0 microg ml(-1), respectively with linear response. No chromatographic interference from the tablet excipients was found. The method described in this paper was validated following the analytical performance parameters required by the USP XXIV, and was successfully applied to the commercial tablets.

Simultaneous multivariate spectrophotometric analysis of paracetamol and minor components (diphenhydramine or phenylpropanolamine) in tablet preparations.

The use of multivariate spectrophotometric calibration is reported for the analysis of two decongestant tablets, where paracetamol is the principal component and diphenhydramine or phenylpropanolamine are the minor components. The resolution of these mixtures has been accomplished without prior separation or derivatisation, by using partial least-squares (PLS-1) regression analysis of electronic absorption spectral data. Although the molar ratios of paracetamol to the minor components were 38:1 and 25:1 respectively, the latter have been determined with high accuracy and precision, and with no interference from tablet excipients. PLS is able to take into account small deviations of paracetamol from linearity in the studied concentration range. The application of classical least-squares (CLS) analysis yields unsatisfactory results, due to the low absorbances of the minor components within the range where all components obey Beer's law.

Chemical, nutritional and technological characteristics of buckwheat and non-prolamine buckwheat flours in comparison of wheat flour.

Chemical, nutritional, and technological characteristics of buckwheat and non-prolamine buckwheat flours in comparison to wheat for celiac patients use have been studied. The results suggested the following conclusions: the 56.5% extraction value for flour obtention is considered good; the buckwheat flour presents methionine and cystine as first limiting amino acids followed by threonine as the second limiting amino acid; the buckwheat flour presents higher content of lysine amino acids than the wheat flour; the buckwheat flour is superior to the wheat flour regarding iron, copper, and magnesium minerals; the buckwheat flour does not present haemagglutinin activity and the tannin content is negligible. Rheological assays indicate that the buckwheat flour does not contain gluten.