Free range rearing of pigs with access to pasture grazing - effect on fatty acid composition and lipid oxidation products.

The influence of free-range rearing, RN genotype and sex on different pig meat quality traits, including intramuscular fatty acid composition and levels of lipid oxidation products, were studied. A total of 60 Hampshire crossbred pigs were reared outdoors for two months with access to green feed, while 60 others were kept indoors, in a 120-m(2)-large pen, throughout the rearing period. From these 120 animals a subsample of 44 animals was chosen for meat quality analysis. Of the three factors studied, the RN genotype had the largest influence on basic technological meat quality traits, whereas the rearing conditions and sex had limited effects. However, outdoor rearing resulted in higher levels of polyunsaturated fatty acids in the intramuscular fat (P=0.026) and in an increased level of vitamin E (P=0.030) compared with the pigs that had been reared indoors. The sex and RN genotype of the animals also had an effect on the fatty acid profile: females had higher levels of unsaturated fatty acids (P=0.003) as well as lower levels of saturated fatty acids (P=0.011) than castrated males. Carriers of the RN(-) allele expressed a higher sum of omega-3 fatty acids (P=0.047) and C22:5 (P=0.012) than did the non-carriers. In a storage study where meat from free-range and indoor reared pigs was stored for 3 months at-20°C, it was shown that the lipid oxidation product malondialdehyde was formed at increased levels in animals that had a higher lean meat percentage than others, i.e. females that were carriers of the RN(-) gene and that were reared outdoors.

Soluble and insoluble oxalate content of mushrooms.

Six different cultivars of edible fungi were bought from a local supermarket in Uppsala, Sweden and three different cultivars of wild growing fungi were harvested from the forest adjoining the city. The edible portions of the raw fungi were then analysed for total and soluble oxalate content. A portion of each fungi was then cooked by first boiling in a small amount of water followed by frying in a small amount of butter. The total oxalate content of the raw, commercially grown mushrooms ranged from 58.9 to 104.1 mg/100 g DM while the values for the total oxalate content of the cooked mushrooms ranged from 48.9 to 124.6 mg/100 g DM. Apart from cultivars ostronskivling and piopino the cultivated mushrooms contained mostly insoluble oxalates. Mushrooms harvested from the forest contained only soluble oxalate with the levels ranging from 29.3 to 40.2 mg/100 g DM in the raw tissue. Cooking marginally lowered the soluble oxalate content of these mushrooms. The levels of soluble and insoluble oxalates of all the mushrooms analysed were low compared to other common oxalate-containing vegetables.