Desempenho de embalagens metalicas para bebidas carbonatadas : avaliação de latas fabricadas por soldagem eletrica frente as latas convencionais

AUTOR(ES)
DATA DE PUBLICAÇÃO

1987

RESUMO

The performance of four kinds of cans, two of them produced by Soudronic and Conoweld welding technologies, and the other two by the conventional process (soldered), was evaluated. With the exception of the can produced by the Conoweld process that was manufactured from tin free steel, the packaging material was tinplate. All of the cans were lacquered internally. The product studied was a lemon soft drink. The shelf-life of the product in the several packagings was determined by storage test within a period of six months at two temperature conditions, 23ºC and 35ºC. The main parameters considered were the internal visual evaluation of the packaging, the concentration of iron and the sensorial evaluation of the product. It was verified that although the tinplate cans presented some small differences among them selves, all of the types of tinplate cans (welded and soldered) presented a good performance during the six months of storage, while the welded tin free steel can suffered a process of accentuated corrosion and the product packaged in it reached concentrations of iron above the permissible tolerance (2ppm at six months of storage) between 90 and 120 days in storage at 23ºC and between 75 and 90 days in storage at 35ºC. For the storage at 23°C, that was the period established for the shelf-life of the product in this packaging, while for the storage at 35°C the shelf-life was between 62 and 75 days in function of the metallic flavor detected in the sensorial evaluation. The sensorial evaluation of the lemon soft drink allowed us to detect the product flavor deterioration during the storage at the two temperature conditions that occured in the product packaged in several types of metalic packaging and also in glass used as reference. In function of that, the limitating factor of the shelf--life of the lemon soft drink in tinplate packagings was the sensorial alteration. The product was considered unacceptable at 150 days of storage at 23ºC and at 105 days of storage at 35ºC. The caracterization of the packagings as to lacquer porosity and protection of the region of welding proved to be directly related to the differences in performance verified among the packagings. The evaluation of samples of the region of welding at time zero and at 180 days of storage at 23°C in Scanning Electron Microscope and X-Ray Diffraction enabled the visualization and confirmation of points of corrosion formation and the existence of defects in the system of packaging lacquering.

ASSUNTO(S)

latas embalagens - industria bebidas - industria

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