No abstract

No abstract

Volatile compounds, odor, and flavor produced by beef from bulls and heifers of the Pirenaica and Friesian breeds were studied during 7 d of aging. The Friesian breed beef had stronger fatty flavor and aftertaste than the Pirenaica, as well as differences in the content of several volatile compounds. Bull beef had stronger liver-like odor and flavor, and bloody flavor that were related to a higher 2-propanone content, while beef from heifers had stronger characteristic flavor. Aging of meat increased characteristic flavor and aftertaste. Ethanal showed a positive correlation with livery flavor and a negative correlation with the characteristic odor. The hexane seems to contribute to fatty flavor, 2-propanone was related to livery and bloody notes, and 2,2,4,6,6-pentamethylheptane to characteristic flavor.

A study was made of differences in the quality of meat from Lacha (L) and Rasa Aragonesa (RA) lambs slaughtered at 12, 24, or 36 kg live weight. Lambs from both breeds were weaned at 25 to 57 d, approximately 11.5 to 18.5 kg live weight, and fed concentrate and barley straw until slaughter at 24 and 36 kg live weight. Hot carcass weight, cold carcass weight, conformation, color, firmness, and thickness of backfat and color of rectus abdominis muscle were recorded on the carcass. Final pH (pHu), instrumental color (L*, a*, b*), myoglobin concentration, chemical composition, and water-holding capacity (WHC) of the longissimus muscle, shear force of the biceps femoris muscle, and iodine values and fatty acid composition of the i.m. and s.c. fat depots were determined. The percentage of fat in the longissimus muscle increased with live weight, and values for RA lambs were higher than those for L lambs. The WHC of meat from RA lambs was lower at 24 kg than at 12 or 36 kg slaughter weight. Live weight and breed had no effect on the shear force of the biceps femoris muscle. There was an increase in myoglobin concentration in the longissimus muscle with increased live weight in both breeds. The fatty acid content of s.c. and i.m. fat, which was not affected by breed, declined with the increase in slaughter weight. The polyunsaturated fatty acid content of the s.c. fat depot increased, whereas that of the i.m. fat depot decreased, with the increase in slaughter weight in both breeds. Subcutaneous fat had a higher content of heptadecanoic acid (17:0) than i.m. fat, and this increased with the increase in slaughter weight. In both depots, there was an increase in oleic acid (18:1) at 12 kg in RA lambs and at 24 kg in L lambs. In the s.c. fat depot, there was a progressive increase in linoleic acid (18:2) content with the increase in live weight in both breeds. There was a higher degree of unsaturation in the s.c. fat of RA lambs than in that of L lambs, which was reflected in the iodine value.

No abstract

No abstract

Volatile compounds of raw beef from Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, and Retinta cattle breeds were studied. Steaks were packaged under 60% O 2 , 30% CO 2 , and 10% N 2 , and 53 volatile compounds were tentatively identified by purge-and-trap extraction and gas chromatography with mass spectrometry after 0, 5, 10, and 15 d of chill storage. The degradation of beef quality with increasing storage time was evidenced by the increase in 2,3,3-trimethylpentane, 2,2,5-trimethylhexane, 3-octene, 3-methyl-2-heptene, 2-octene, and 2-propanone and by the decrease in dimethyl sulfide. Consequently, some of the volatile compounds, which are believed to be formed by thermal degradation of meat, might be formed during chill storage, and the rate of formation of some was dependent on the specific compound. Materials and Methods I N THIS STUDY, 30 INTACT YOUNG BULLS FROM 5 DIFFERENT LOCALSpanish cattle breeds (6 animals per breed) were used: Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, and Retinta. These are all beef cattle for meat production, except for Parda Alpina, which can be considered a dual-purpose breed (dairy and beef ). The Parda Alpina breed comes from Switzerland, but it was introduced in Spain at the end of the century (MAPA 1986). Morucha and Retinta cattle are reared in extensive livestock systems from the West and South of Spain, whereas Rubia Gallega, Pirenaica, and Asturiana de los Valles are reared in semi-extensive livestock systems from the Northern Spain. After weaning, animals were allotted into groups to fatten (6 animals per breed and group) at the Agricultural Research Service, DGA (Zaragoza, Spain). Young bulls were handled on identical farming conditions in order to eliminate the effect of livestock system. Fattening period started when young bulls were 6 to 8 mo old and weighed 220 to 260 kg. During this period, animals were finished on commercial concentrate and barley straw, both ad libitum.Animals were slaughtered at the abattoir in Zaragoza, Spain (Mercazaragoza), according to the current sanitary legislation (BOE 1993), at approximately 470 kg live weight (group average)

No abstract