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Abstract Physicochemical characteristics of Semimembranosus and Biceps femoris muscles from 24 dry cured Iberian hams were analysed. The hams were salted with different amounts of salt (60 g kg−1, HS, and 30 g kg−1, LS, w/w) and then ripened at different temperatures (traditional processing, T, versus modified processing, M). The processing conditions did not significantly affect the moisture content and the chloride molality of Semimembranosus and Biceps femoris muscles (p>0.05) throughout ripening, although daily weight losses were significantly affected (p<0.01). The effect of the processing conditions on water activity was also rather limited as it was only significant at the drying stage. Colour a* values and chroma were significantly higher in Semimembranosus muscles from T hams than from M ones (p<0.01). Muscles from hams elaborated in a traditional system showed a higher number of tyrosine crystals than muscles from hams processed in a modified one, though only to a significant extent in Semimembranosus muscle (p<0.05). The salt concentration was higher in HS than in LS hams. HS hams showed higher weight losses in the salting and postsalting stages, owing to a more intense osmotic dehydration.

The effects of pig rearing conditions (free-range system based on acorn and pasture versus confinement on a concentrate feed) and muscle location (biceps femorisand semimembranosus)on sensory characteristics of dry-cured Iberian hams were studied. Muscle samples were sensorily evaluated for appearance, texture, aroma and flavor attributes by a trained panel. Muscle location significantly affected texture and appearance traits. Semimembranosusmuscle was harder, dryer and more fibrous than was biceps femorismuscle. Rearing conditions significantly affected sensory attributes related to fatty acid composition and lipid content of meat. Hams from free-range pigs showed higher scores in oiliness, brightness of the lean, marbling, and aroma and flavor traits than did hams from pigs raised in confinement.

The effect of feeding regime—free—range reared on acorn and pasture, or in confinement with and without the incorporation of 100 mg/kg α-tocopheryl acetate to pig mixed feeds—on volatile alde hyde content in Biceps femorismuscle throughout the ripening of Iberian ham was studied. Saturated aldehydes from 4 to 10 carbon chain and two diunsaturated aldehydes, 2,4-nonadienal and 2,4- decadienal, were found in ham samples. Volatile aldehyde evolution was not affected by feeding regime throughout ripening of hams. Volatile aldehyde content and individual aldehydes rose mark edly from Day 0 to Day 210 (p< 0.05), and afterwards decreased to Day 700 (p< 0.05). Both α- tocopheryl acetate supplementation and feeding on acorn and pasture significantly decreased the total and individual aldehydes in Biceps femorissamples at Days 0, 210 and 700 (p< 0.05) in compari son with muscle samples from pigs fed the non-supplemented diet.

The unsaponifiable fraction of subcutaneous fat of dry-cured Iberian hams from pigs fed on different systems during the finishing-fattening period and its feasibility as a method for classifying the hams according to the pigs' feeding background are studied. Unsaponifiable fraction and n-alkane content of subcutaneous fat from ten dry cured hams from Iberian x Duroc pigs raised on two different man agement systems (Montanera,fed extensively on acorns and pasture, and Pienso,fed on a concentrate diet) are analyzed. The proportion of unsaponifiable material and n-alkanes [pentadecane (n-C15), heptadecane (n-C17), octadecane (n-C18), nonadecane (n-C19), eicosane (n-C20) and pentacosane (n-C25)] were higher (P< 0.05) in hams from pigs raised under extensive conditions than in those from pigs receiving concentrate feeds. The unsaponifiable fraction assay of the fat from dry-cured Iberian hams is a promising technique for classifying hams based on the pigs' feeding background.

Sixty female mice were injected neonatally with testosterone propionate. This led to an increase in body weight at 56 days (P<0.01) and a reduction in carcass fat (P<0.005). Food conversion ratio from 28 to 49 days was lower in the treated group than in the controls (P<0.01). The data indicate that treated females can reach values similar to those of males.Histological studies revealed a lack of luteal tissue in treated females at 56 days. This effect might be due to a modification in the nervous control of ovarian activity. Growth hormone secretion was higher in treated females than in controls (P<0-05). These results suggest that androgenization of females to achieve the performance characteristics of intact males could have important implications in meat production.Journal of Endocrinology(1989) 120,281–285