Propiedades emulsificantes y espumantes de las proteínas de harina de cacahuate (Arachis hypogaea Lineau)

The functional properties of proteins present in peanut (Arachis hypogaea Lineau) flour were studied. The influence of the pH and protein solubility on emulsifying and foaming properties of peanut flour was evaluated. The isoelectric point (Ip) of these proteins was found at the pH of 4,0; and the isoelectric region between pH 3,0 and 5,0. The evaluated surface properties decreased in the isolectric region. The emulsifying activity and time stability (30 and 120 minutes) significantly decreased at the pI; the emulsifying stability at the temperature of 80°C decreased in all the isoelectric region until the pH of 6,0. The foaming activity had the best values at the pH of 2,0. The correlation between protein solubility and surface properties were more significant for emulsifying properties than for foaming properties.Se estudiaron las propiedades funcionales de las proteínas presentes en la harina de cacahuate (Arachis hypogaea Lineau). Fue evaluada la influencia que tienen el pH y la solubilidad proteica sobre las propiedades emulsificantes y espumantes de las proteínas de harina de cacahuate. El punto isoeléctrico (pI) de estas proteínas se encuentra a pH 4,0; mientras que la región isoeléctrica está entre los valores de pH de 3,0 y 5,0. Las propiedades de superficie evaluadas disminuyeron en la región isoeléctrica, siendo que la actividad emulsificante y la estabilidad emulsificante en los tiempos de 30 y 120 minutos disminuyeron fuertemente en el pI; las estabilidades emulsificantes en relación a la temperatura (80 ºC) diminuyeron en toda la región isoeléctrica extendiéndose hasta el pH 6,0. La actividad espumante mostró sus mejores valores a pH 2,0. Las correlaciones entre la solubilidad protéica y las propiedades de superficie fueron más importantes para las propiedades emulsificantes que para las espumantes

Effects of drying and pretreatment on the nutritional and functional quality of raisins

The close relationship between the consumption of fruits and health status stems from the nutritional and non-nutritional compounds found in fruits which play a key role in the prevention of different diseases. However, fruit processing and storage greatly affect fruit compounds. The aim of the present work was to study the influence of processing on the stability of macro and micronutrients present in grapes, with a view to recommending products that provide the highest nutritional quality and the best health conditions. The study focused on fruit dehydration treatments. Conventional and microwave-assisted air-drying processes were used to obtain raisins. Dehydration caused a decrease of all grape compounds studied excluding total phenols. Moreover, compared to conventional processing, microwave-assisted drying produced greater losses of ascorbic acid in the grape and increased pectin solubilization with a consequent change in texture. However the microwave-dehydrated samples showed higher antioxidant activity. © 2011 The Institution of Chemical Engineers.The translation of this paper was funded by the Universidad Politecnica de Valencia.Carranza Concha, J.; Benlloch Tinoco, M.; Camacho Vidal, MM.; Martínez Navarrete, N. (2012). Effects of drying and pretreatment on the nutritional and functional quality of raisins. Food and Bioproducts Processing. 90(2):243-248. https://doi.org/10.1016/j.fbp.2011.04.002S24324890

Antioxidant compounds recovery from Juçara residue by thermal assisted extraction

This study aimed to recover bioactive compounds by solid-liquid extraction from the agro-industrial residue obtained during juçara fruits processing into pulp. A preliminary study using different solvents (methanol, ethanol and water) indicated ethanol in aqueous solution as the best solvent for antioxidants recovery. Then, a Box-Behnken design was applied considering as independent variables the solvent composition (3070% ethanol in water), temperature (3070 °C) and time (3060 min), in order to evaluate the effects of these factors on antioxidant activity in juçara extract. Results showed that the extracts with higher antioxidant activity were obtained using 30% ethanol at 70 °C for 60 min; measurements included ABTS and DPPH assays, determination of total phenolic content and total monomeric anthocyanins. Furthermore, the effect of pH in antioxidants recovery was evaluated. For this purpose, the 30% ethanol solution was acidified to pH 1 and 2 with HCl. Principal component analysis showed the formation of three distinct groups: one characterized by high bioactive compounds content (pH 1.0), another with superior antioxidant activity (pH 5.75, non-acidified), and finally the group at pH 2 presenting the worst concentrations in the evaluated responses. HPLC analysis showed the presence of cyanidin-3-O-rutinoside and cyanidin-3-O-glucoside in the extracts. Therefore, the conventional solid-liquid extraction using renewable solvent can be successfully applied to recover bioactive compounds from juçara residue, which can be used by different food industries.The authors gratefully acknowledge the institutions: Coordenação de Aperfeiçoamento Pessoal deEnsinoSuperior (CAPES), Universidade Federal do Rio de Janeiro, Embrapa Agroindústria de Alimentos and University of Minho by the financial support of the research work and Juçaí Alimentos for the juçara residue. Ricardo N. Pereira gratefully acknowledge to Portuguese Foundation for Science and Technology (FCT) the financial grant with reference SFRH/BPD/ 81887/2011.info:eu-repo/semantics/publishedVersio

Mudanças nos compostos bioativos e atividade antioxidante de pimentas da região amazônica.

A Embrapa Amazônia Oriental possui um Banco Ativo de Pimenteira com diferentes genótipos do gênero Capsicum, os quais ainda não foram analisados, quanto às suas características funcionais e capacidade antioxidante. Este estudo objetivou determinar os teores de ácido ascórbico, compostos fenólicos, carotenoides totais e a atividade antioxidante total, em frutos imaturos e maduros de genótipos de pimentas Capsicum spp. As concentrações de vitamina C (100,76-361,65 mg 100 g-1 nos frutos imaturos e 36,70-157,76 mg 100 g-1 nos maduros) decresceram com a maturação dos frutos. Carotenoides totais não foram detectados nos frutos imaturos, porém, nos frutos maduros, observaram-se valores de 73,80-1349,97 mg g-1, em função do genótipo. Os teores de compostos fenólicos aumentaram nos frutos maduros (147,40-718,64 mg GAE 100 g-1), para oito dos nove genótipos avaliados. Os frutos de pimenteira apresentaram significativa atividade antioxidante (55,02-92,03 mM trolox g-1 nos frutos imaturos e 39,60-113,08 mM trolox g- 1 nos maduros). Concluiu-se que o grau de maturação dos frutos influenciou nos teores de compostos bioativos dos genótipos estudados. Destacaram-se, como genótipos promissores com potencial para serem utilizados em programas de melhoramento genético, IAN-186301 e IAN-186324, pelos altos teores de carotenoides totais; IAN-186301, IAN-186311, IAN-186312 e IAN-186313, com relação às altas concentrações de ácido ascórbico; IAN-186304 e IAN-186311, pelos altos teores de compostos fenólicos; e IAN-186311, para atividade antioxidante