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)