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Albumin from wheat bran was subjected to proteolysis. Molecular weight profile and particle size distribution were analyzed in the hydrolysates, which were later assayed in both crude extracts and surfaces of apple mesocarp in order to test their effect on polyphenol oxidase activity and enzymatic browning; the latter measured as L*, hue° and chroma*. Both the electrophoretic pattern and the size distribution showed, upon the hydrolysis, the appearance of aggregates with higher molecular weight than albumin. Polyphenol oxidase in crude extracts of apple was inhibited up to 40% by hydrolysates in a mixed way. The application of hydrolysates to mesocarp resulted in the impartment of a slight brownish color to the tissue and there were significant differences on L*, hue° and chroma* with respect to treatments but not with respect to time (P < 0.05). PRACTICAL APPLICATIONS The hydrolysates produced from wheat bran albumin give their color to apple tissue when applied on its surface and also inhibit apple polyphenol oxidase, so the color is maintained with time. This property could be advantageous in situations where both color imparting and control of the enzymatic browning are desirable. Important aspects to consider are: the imparted color was nice by sight and wheat bran is an inexpensive source of proteins.

Chemical fungicides that are related with resistant strains develop negative effects on human health and environment. Propolis is a resinous substance collected by bees with positive effects on human health and inhibitory activity against Alternaria alternata. Caffeic acid phenethyl ester (CAPE) is a component of the propolis. The objective of this experiment was to test the effect of CAPE on fungi infecting tomato fruit using as a model the pathosystem A. alternata-tomato. CAPE was chemically synthesized in our laboratory and analysed with nuclear magnetic resonance spectroscopy. Different concentrations (0, 16, 32, 48, 64, 80, 90 and 100 lm) of CAPE were tested on A.

BIOTECNOLOGÍA Y CIENCIAS AGROPECUARIAS RESUMENEl salvado de trigo se destina principalmente al consumo animal, por lo que algunos de sus componentes son subutilizados, representando oportunidades de valor agregado. Constituye las capas externas del grano y contiene hasta 18 % en peso de proteínas con mejor calidad que las de la harina. Estas proteínas no son aprovechadas debido a que la mayoría están protegidas por una matriz de polisacáridos, indigerible para el sistema gastrointestinal humano, por lo que es necesaria su extracción. Tradicionalmente, las proteínas de salvado han sido recuperadas mediante extracción alcalina y se han propuesto como ingredientes para la elaboración de productos alimenticios. Sin embargo, su uso es casi inexistente, debido a que los procesos de extracción son agresivos y no redituables. El objetivo del presente trabajo fue describir las propiedades de las proteínas del salvado de trigo, así como sus usos potenciales. Entre sus propiedades destacan la digestibilidad, el perfil de aminoácidos y la capacidad de absorción de grasa. La fracción soluble en agua de estas proteínas, por su fácil extracción, podría tener valor agregado al utilizarse en tecnologías emergentes: como fuente de pépti-dos bioactivos, en la producción de nanopartí-culas con aplicaciones industriales o como matrices para procesos de biomineralización artificial.PALABRAS CLAVE: proteínas de cereales, subproductos agroindustriales, tecnologías emergentes. ABSTRACTWheat bran is mainly intended for animal consumption and some of its components are underutilized, representing value-added opportunities. It forms the outer layers of the grain and contains up to 18 % by weight of proteins of better quality than those of flour. These proteins are not exploited because most are protected by a matrix of polysaccharides, which is indigestible by the human gastrointestinal system, so their extraction is necessary. Traditionally, wheat bran proteins have been recovered by alkaline extraction and have been proposed as ingredients for the manufacture of foodstuffs. However, their use is almost non-existent because the extraction processes are aggressive and not profitable. The aim of the present review is to present the properties of wheat bran proteins, as well as, their potential uses. Among their properties, the digestibility, lipid absorption capacity and aminoacid pattern are highlighted. The water soluble fraction of these proteins, because of their easy extraction, could have an added value from the perspetive of emerging technologies, for example, as a source of bioactive peptides, in the production of nanoparticles with industrial applications or as matrices for artificial biomineralization processes.

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The inhibitory capacity of the globulin fraction of wheat bran against the diphenolase activity of mushroom tyrosinase, using L-tyrosine as substrate, was evaluated. Enzyme kinetics was monitored in the presence of globulin solutions by measuring the absorbance at 475 nm. LineweaverBurk plots were drawn in order to determine V max , K m , and type of inhibition. Results showed that globulins from wheat bran competitively inhibited, the activity of mushroom tyrosinase with a K I of 0.79%(w/v). The degree of inhibition was 24% at 2 mM of the substrate L-tyrosine.