ESR and optical absorption studies of gamma- and electron-irradiated sugar crystals

Electron spin resonance (ESR) studies of the free radicals induced in gamma- or electron-irradiated sugar crystals were performed. The number of radicals increases linearly, pointing out that this material can be used as a dosimeter. The optical absorption studies show the presence of several distinctive bands in the infrared and UV region, whose intensity changes with the irradiation dose. An interpretation of these results in terms of the formation of free radicals and possible crosslinking along the sugar molecular chains is presented.

[Effect of the infestation by Prostephanus truncatus Horn, Sitophilus zeamais Mots, or Sitotroga cerealella Oliver, on the concentration of amino acids in corn proteins]. / Efecto de la infestación por Prostephanus truncatus, Horn, Sitophilus zeamais, Mots, o Sitotroga cerealella, Oliver, en la concentración de amino ácidos en la proteína del maíz.

The amino acid concentration in the protein of batches of corn kernel subjected to infestation by P. truncatus, S. zeamais or S. cerealella was measured. For each insect species three development stages were studied, larvae, at the emergence of the first generation, and longer. Differences between the control and each of the nine infested batches were observed for most of the amino acids. The only pattern of differences consistent in magnitude, significance and sign, was a fall in leucine and isoleucine and a raise in tryptophan concentration. The chemical scores of all samples were similar to the control, except in the case of infestation by larvae of S. cerealella in which it decreased 15%.

Efecto de la infestacion por Prostephanus truncatus, Horn, Sitophilus zeamais, Mots, o Sitotroga cerealella, Oliver, en la concentracion de aminoacidos en la proteina del maiz. / Effect of the infestation by Prostephanus truncatus, Horn, Sitophilus zeamais, Mots, or Sitotroga cerealella, Oliver in the concentration of amino acids in corn proteins

Se analizo la concentracion de aminoacidos en la proteina del maiz de diferentes lotes infestados, en condiciones de laboratorio, con P. truncatus, S. zeamais o S.cerealella en las etapas de larva, al emerger la primera generacion y en periodos mayores. Se observaron diferencias en la concentracion de la mayoria de los aminoacidos entre el lote testigo y los nueve lotes experimentales, pero el unico patron consistente en cuanto a magnitud, significancia y signo de las diferencias, fue una disminucion en leucina e isoleucina, y un aumento en triptofano. La calificacion quimica mostro cambios minimos, excepto en el caso de la infestacion con larvas de S.cerealella, en el que disminuyo en un l5% con respecto al lote testigo

[Changes in the concentration of components of corn grain infested with Prostephanus truncatus Horn, Sitophilus zeamais Mots, or Sitotroga cerealella Oliver]. / Cambios en la concentración de algunos componentes del grano de maiz infest ado por Prostephanus truncatus, Horn, Sitophilus zeamais, Mots, o Sitotroga cerealella, Oliver.

Quantitative changes in the chemical composition of stored corn infested with the grain insects Prostephanus truncatus, Sitophilus zeamais or Sitotroga cerealella were studied in the laboratory under the following conditions for each species: after infestation of samples by larvae, at the emergence of the first generation and after more than one generation. Changes occurred in the composition of all samples, the effect being more marked with larvae. Although no consistent pattern was evident, the nitrogen concentration of infested samples generally increased and the ether extract decreased. The total amounts of each constituent decreased in all samples, with up to 19% loss of energy content. Some of these changes may be attributed to selective feeding by each species, on specific regions of the maize kernel; this phenomenon was more apparent in the case of samples infested with larvae.