Physical, mechanical and hydration kinetics of particleboards manufactured with woody biomass (Cupressus lusitanica, Gmelina arborea, Tectona grandis), agricultural resources, and Tetra Pak packages

Lignocellulosic wastes resulting from agricultural activities as well as Tetra Pak residues from urban centres can cause significant levels of pollution. A possible action to minimize this problem is to use them in the production of particleboards. The purpose of this study was to evaluate the physical, mechanical, and hydration properties of particleboards manufactured with the mixture of woody biomass (Cupressus lusitanica, Gmelina arborea, and Tectona grandis) and either agricultural wastes [pineapple leaves (Ananas comosus) and palm residues (Elaeis guineensis)] or Tetra Pak residues (TP). The results show that the particleboards prepared with TP and woody biomass can reduce the swelling and water absorption in up to 40% and 50% compared with particleboards without TP. Also, these particleboards had increased flexure resistance and shear stress (up to 100%) compared with those without TP. On the contrary, particleboards prepared with pineapple leaves in combination with woody biomass showed the lowest mechanical properties, particularly for tensile strength, hardness, glue-line shear, and nail and screw evaluation.Los desechos lignocelulósicos resultantes de las actividades agrícolas, así como los residuos de Tetra Pak de los centros urbanos pueden causar niveles significativos de contaminación. Una posible acción para minimizar este problema es usarlos en la producción de tableros de partículas. El propósito de este estudio fue evaluar las propiedades físicas, mecánicas y de hidratación de tableros de partículas fabricados con la mezcla de biomasa leñosa (Cupressus lusitanica, Gmelina arborea y Tectona grandis) y residuos agrícolas [hojas de piña (Ananas comosus) y residuos de palma (Elaeis guineensis)] o residuos de Tetra Pak (TP). Los resultados muestran que los tableros de partículas preparados con TP y biomasa leñosa pueden reducir la hinchazón y la absorción de agua hasta en un 40% y 50% en comparación con los tableros de partículas sin TP. Además, estos tableros de partículas tenían una mayor resistencia a la flexión y al esfuerzo cortante (hasta 100%) en comparación con aquellos sin TP. Por el contrario, los tableros de partículas preparados con hojas de piña en combinación con biomasa leñosa mostraron las propiedades mecánicas más bajas, particularmente para la resistencia a la tracción, la dureza, el corte de la línea de pegamento y la evaluación de clavos y tornillos.Universidad Nacional, Costa RicaEscuela de Químic

Effect of cold chain temperature abuses on the quality of frozen watercress (Nasturtium officinale R. Br.)

The objective of this work was to study the effect of temperature abuses on the colour and vitamin C content of a new frozen vegetable, watercress (Nasturtium officinale R. Br.). The vitamin C content, expressed as ascorbic (AA) and dehydroascorbic (DHAA) acids, and colour, expressed in the Hunter Lab parameters, were evaluated along a plan of temperature abuses, based on a real situation for a four month frozen storage period. A comparison between the hue angle and AA experimental data and prediction models, using kinetic parameters determined under isothermal conditions, was also run. The colour showed some variation, namely on the parameters L, a, TCD (Total Colour Difference) and hue angle. Although, during the temperature abuses, some fluctuation was observed, no vitamin C degradation or major colour changes occurred. A zero-order and a first-order prediction models fitted well the experimental data for the hue angle and AA behaviour with temperature abuses, respectively. In general, the frozen watercress colour and vitamin C content were not impaired by the imposed temperature abuses. This work will help to predict and understand the sensory and nutritional quality changes of frozen watercress that might occur during frozen storage and distribution in the cold chain under the used conditions