RESUMO
One hundred and five samples of pig backfat were assessed for appearance (colour and translucency) and hardness. The fatty acid profile of a selected subset of 50 samples was determined. Increased yellow colour was associated with increased linoleic and α-linolenic acid percentages. Increased translucency and fat softness were associated with decreased percentages of palmitic and stearic and oleic acid and a concurrent increase in the proportions of linoleic and α-linolenic acid. Oleic acid was found to be the single highest component (33.0-45.4%) and linoleic to show the greatest variation in range (9.8-28.4%).
RESUMO
The evolution of NOx from grass and maize silages was measured using chemiluminescence in samples kept in airtight containers, in the silos and in a 750 kg mass removed to a mixer waggon. Measurements were made on the grass and maize silos in two consecutive years. The results show that there is continuous evolution of NOx after silos have been opened and that high concentrations persist in the mass which are rapidly released on agitation at the feed-out. The maximum recorded concentrations of NO and NO2 were 1985 and 152 ppbv respectively. These values are orders of magnitude greater than for rural background levels and exceed the maximum hourly exposure of 50 ppbv for NO2 recommended by the UK expert panel for quality standards.