Multivariate study of different beef quality traits from local Spanish cattle breeds.

Different raw beef quality traits from four local Spanish cattle breeds were studied using correlation, factorial, discriminant and multiple regression analysis. The following variables were studied after 0, 5, 10 and 15 days of storage under 60% O2, 30% CO2 and 10% N2 modified atmosphere packaging (MAP): colour physical variables, meat pigments, sensory degradation of odour and colour, microbial counts, thiobarbituric acid (TBA), pH, drip loss, lipid composition and volatile compounds. The degradation of raw beef quality was related to the increase in 2,3,3-trimethylpentane, 2,2,5-trimethylhexane, 3-methyl-2-heptene, 2-octene, 3-octene, 2-propanone, Enterobacteriaceae and aerobial plate counts (APC), metmyoglobin (MMb), lightness (L*), yellowness (b*), drip loss and TBA. Among these variables, TBA, b* and MMb may be useful in evaluating raw beef quality. No variables related to fat, except for TBA, including pH were limiting factors of the colour and odour shelf-life of raw beef under MAP. Each breed had some characteristics that were unique and these differences may influence the stability of meat to oxidation depending on myoglobin concentration and the polyunsaturated fatty acid (PUFA)/saturated fatty acid (SFA) ratio.

Characteristics of Lacha and Rasa Aragonesa lambs slaughtered at three live weights.

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.

Technological suitability of mutton for meat cured products.

A comparative study on the technological suitability of mutton and pork for meat cured products was carried out. One type of cured dry sausages was made of mutton and the other of pork, using the same formulation and technological conditions. Thus, the evolution of physico-chemical and microbiological parameters, as well as colour and texture were measured at three different stages of the process: after mincing, after fermentation and after drying. The sensory parameters were assessed in the final product. Both mutton and pork had a similar technological aptitude during processing of cured dry sausages, with a similar evolution of the pH value, a(w) and Lactobacilli counts. The main differences between both types of sausage were observed in texture, colour and in the organoleptic characteristics, having mutton sausages greater cohesivity and more stable and redder colour than pork sausages. Besides, mutton sausages showed an aroma, flavour and texture that were not desirable for the panellists.

Cured colour development during sausage processing.

A study of colour evolution in dry cured sausage manufactured using industrial technology was made. Parameters which define changes related to nitrosation during curing were determined. The main changes in the colour characteristics of Spanish sausage took place during the fermentation stage. pH, nitrate and nitrite concentration, pigment nitrosation index, pigment discoloration index, a(∗), b(∗), C(∗) and H(∗) values decreased during this stage. However, the nitrosation of the myoglobin pigment continued during the whole curing process. The percent conversion of total pigments to the cured nitric oxide heme pigment form was about 70% in the minced mix, and it increased gradually to about 90% in the final product. During fermentation nitrites reacted with myoglobin (Mb) to form nitrosomyoglobin (NOMb) and metmyoglobin (MetMb), which reduced to NOMb during the drying process.