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Publications (5)5.84 Total impact

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    ABSTRACT: The water-soluble protein profile of the seeds of green, red, and yellow Theobroma cacao L. fruits has been determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-ToF-MS). The seeds were powdered under liquid nitrogen and defatted. The residues were dialyzed and lyophilized. The obtained samples were suspended in the matrix solution of sinapinic acid. The obtained MALDI mass spectra showed the presence of a wide number of proteins with molecular weight ranging from 8000 to 13,000 Da and a cluster of peaks centered at 21,000 Da that were attributed to albumin. The abundance of this peak was found to depend on the different portion of the seed (husk, apical and cortical parts); however, the MALDI mass spectra obtained from the different varieties of cocoa were practically superimposable. Changes in the protein profiles were also observed after the cocoa seeds were treated by fermentation and roasting, which are processes usually employed for the commercial production of cocoa.
    Rapid Communications in Mass Spectrometry 07/2011; 25(14):2035-42. · 2.51 Impact Factor
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    ABSTRACT: a b s t r a c t The contents of protein and non-protein (free and protein-bound) tryptophan and of proteins in cocoa beans of various origin were determined. Protein concentrations varied from 11.8 g/100 g in beans from the Dominican Republic to 15.7 g/100 g in roasted beans from the Ivory Coast. The highest protein tryp-tophan content was found in cocoa beans from Ecuador. Madagascar beans had the highest value of free tryptophan and Echeandia the lowest (17.26 and 6.39 mg/100 g, respectively). Tryptophan was bound to water-soluble proteins as well as to proteins soluble in buffer solution (pH 8.9) and in 70% ethanol. In particular, Dominican Republic cocoa contained the highest amount of tryptophan bound to water-solu-ble proteins. Very little tryptophan was linked to proteins soluble in alkaline or ethanol solutions, and values ranged from 0.96 to 3.04 and from 0.24 to 1.21 mg/100 g of dry defatted cocoa sample, respectively.
    Food Chemistry 01/2011; 124(1). · 3.33 Impact Factor
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    ABSTRACT: Cereals and legumes are the major source of protein in the human diet. There is little information on the presence of non-protein tryptophan, one of the essential amino acids less represented in the vegetable proteins. Our results show that tryptophan is present not only in the free-form but also is linked either to water soluble proteins or to proteins extracted at pH 8.9 both in cereal and legume flours. As regards the cereals, wheat and spelt contain the highest content of protein tryptophan and maize the lowest. Spelt, followed by barley and pearl millet flours, contains the highest amounts of free tryptophan and the rice the lowest. In addition, spelt flour shows the highest levels of tryptophan linked to both water soluble and buffered protein fractions, whereas rice contains the lowest amounts of protein-bound tryptophan. Among the legume flours, soybeans show the highest value in protein tryptophan and peas the lowest. Chick peas contain the highest concentrations of both free and protein-bound tryptophan water soluble fraction. This last fraction appears absent in broad bean, lentil and soybean flours. In addition, beans are shown to contain the highest levels of tryptophan linked to proteins extracted at pH 8.9, and peanuts the lowest values both as free and protein-bound forms.Considering that tryptophan is one of the limiting amino acids of the biological value of vegetable proteins, the determination of non-protein tryptophan in food is very useful in calculating the score.
    International Congress Series 11/2007; 1304:227-232.
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    ABSTRACT: The content of proteic and nonproteic (free and protein-bound) tryptophan and of proteins in quinoa, wheat, rice, maize, barley, oat, rye, spelt, sorghum and millet flours was determined. Protein content and proteic tryptophan of quinoa were similar to that of wheat and spelt, but higher than in other cereals. Free tryptophan in quinoa flour showed values similar to those of wheat, oat and sorghum Kalblank, lower than those of barley, spelt and pearl millet, but higher than in rice, maize, rye, sorghum DK 34 – Alabama hybrid. In addition, nonproteic tryptophan appears bound both to water soluble proteins and to proteins soluble at pH 8.9. The results are discussed regarding the importance of the nonprotein tryptophan fraction, the only one able to enter the brain, that is more easily absorbed, so guarantees a greater amount available for uptake by the central nervous system.
    Food Chemistry. 01/2007;
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    ABSTRACT: The contents of protein and non-protein (free and protein-bound) tryptophan and of proteins in the flours of nine legume seeds were determined. Lupins and soybeans showed the highest protein concentrations, followed by groundnuts, beans, broad beans, lentils, vetches, chick-peas, and peas. Protein tryptophan content is higher in soybeans and lower in peas (502 and 192 mg/100 g of dry flour, respectively) than in the other legumes, which also contain non-protein tryptophan. Chick-peas show the highest value of free tryptophan and groundnuts the lowest (58.2 and 2.24 mg/100 g of dry flour, respectively). Tryptophan appears to be bound to water-soluble proteins and to proteins soluble at pH 8.9. In particular, chick-peas contain a high amount of tryptophan bound to water-soluble proteins, followed by beans. The results are evaluated, considering the importance, not only of protein, but also non-protein tryptophan, for assessing the nutritive value of a protein in foods.
    Food Chemistry. 01/2007;