Performance of aluminium trays for sterilized products

Autor: Léa Mariza de Oliveira, José Ricardo Goncalves, Valéria D Anjos, Rosa Maria Vercelino Alves, Sylvio Alves Ortiz
Rok vydání: 1995
Předmět:
Zdroj: Packaging Technology and Science. 8:55-72
ISSN: 1099-1522
0894-3214
Popis: The performance of a retortable semi-rigid aluminium container, of square shape, net capacity 330 ml and with a heat sealable lid, produced in Germany by Alcan, was studied relative to parameters of filling, thermal processing and heat sealing. Tests were applied to packages containing water (275 and 295g) and a solution of carboxymethyl cellulose (CMC) at 1.25% (295 and 306g). The thermal processing was applied under stationary and rotary (at 8, 10 and 12r.p.m.) conditions. Heat sealing was evaluated by visual aspect, integrity, burst resistance, tensile strength and thickness reduction. The influence of contamination (presence of water, water vapour, CMC and vegetable fat) on the heat sealing area was also examined. Rotary thermal processing has been proved more advantageous in comparison with a stationary process, mainly for a high viscosity model medium (CMC solution at 10000 cP at 25°C), as it reduces the sterilization time to about 50%. The headspace volume measured by the destructive method indicated small variations, significant at the level of 5%, when pre- and post-thermal processing values were compared. This is due to the presence of entrapped air in the test product, which is released during thermal processing. The seal resistance measured by the increase in internal pressure (burst) resistance showed average values of 26-29 p.s.i. obtained for packages containing water or CMC examined pre- and post-stationary and rotary (8r.p.m.) thermal processing. Such average values guarantee the container good performance. At the 5% level, there was no significant difference in burst resistance for the container processed with or without rotation, containing either water or CMC, at any of the filling levels analysed. Contamination of the heat sealing area, evaluated through the burst resistance, indicated the non-existence of any significant difference at the level of 5% and the minimum value of 25 p.s.i. can be said to be satisfactory for all the treatments studied. For the two test products, at the filling levels studied, the compression resistance measured before heat-treatment showed average maximum load values ranging from 84.5 to 87.8 kgf (deflection varying from 4.7 to 5.0mm). After both stationary and rotary (8r.p.m.) thermal processing, the minimum crushing yield load value was around 83.5 kgf. Such values are acceptable for this kind of package.
Databáze: OpenAIRE
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