K. Insausti

Shelf life of beef from local Spanish cattle breeds stored under modified atmosphere

Beef steaks from six Spanish cattle breeds (Asturiana de los Valles, Morucha, Parda Alpina, Pirenaica, Rubia Gallega and Retinta) were packaged under modified atmosphere (60% O(2), 30% CO(2) and 10% N(2)). Water loss, pH, thiobarbituric acid values (TBA), aerobic plate counts, lactic acid bacteria and Enterobacteriaceae counts, CIE L*a*b* colour values and the sensory properties of odour and colour were recorded before packaging (day 0) and after 5, 10 and 15 days of storage. A significant interaction (P<0.05) between breed and storage time was found for all variables, except water loss. Values of pH were between 5.3 and 5.6; maximum water loss (2.64%) was reached after 10 days of storage; aerobic plate counts, lactic acid bacteria and Enterobacteriacea counts were lower than 10(7) CFU/g, and L* increased with storage time while a* decreased (P<0.05). The maximum shelf life of beef assessed by sensory evaluation (regarding colour and odour degradation) was between days 5 and 10 in meat from Retinta breed and between days 10 and 15 in meat from the other breeds, shelf life was probably limited by lipid oxidation.

Colour stability of beef from different Spanish native cattle breeds stored under vacuum and modified atmosphere

Beef steaks from five Spanish cattle breeds were submitted to three packaging conditions: (a) 15 days under vacuum, (b) 15 days under modified atmosphere (MAP) (60% O(2), 30% CO(2) and 10% N(2)), and (c) 10 days under vacuum plus 5 days more under MAP. CIE L(∗)a(∗)b(∗) coordinates, chroma (C(∗)) and hue (H(∗)), relative concentration of myoglobin, oxymyoglobin and metmyoglobin at the meat surface and sensory evaluation of colour were determined 0, 5, 10 and 15 days after packaging. Beef under MAP showed higher lightness (L(∗)) and hue (H(∗)) and lower redness (a(∗)) and chroma (C(∗)) than beef under vacuum. Colour of beef under MAP was not acceptable after 15 days of storage, due to the high metmyoglobin concentration. Yellowness (b(∗)) was the indicator of differences due to ageing and differences in colour between breeds were related to L(∗), a(∗) and H(∗) values. Packaging conditions had a greater effect on beef colour than breed, but breed differences might change with packaging atmosphere. Both packaging and breed are major factors in packaged beef quality.

The effects of olive oil emulsified alginate on the physico-chemical, sensory, microbial, and fatty acid profiles of low-salt, inulin-enriched sausages

This paper examines variations in the quality of low-salt, inulin enriched Pamplona-style chorizo, in which some of the pork back fat was replaced with olive oil. Four different sausage formulations were prepared in which 50% of the pork back fat was replaced with olive oil emulsified with alginate and 58% of the sodium chloride was replaced with 20% potassium chloride and 38% calcium chloride. Four lots were prepared, three with 3%, 6% and 10% proportions of added inulin were labeled O-I 3%, O-I 6% and O-I 10%, respectively; while one, lot O, was without inulin. These four formulations were compared with a control manufactured according to the traditional formula using pork back fat. The various lots were tested for proximate analysis, pH, processing loss, water activity, lactic acid bacteria, Salmonella and Listeria monocytogenes, physico-chemical composition, instrumental colour (CIE L*a*b*), texture profile and fatty acid composition during mixing and at days 3, 10, 17, 24 and 31 of the drying process. A sensory evaluation was also performed by a seven-member trained panel, to obtain a descriptive analysis of the taste, texture and appearance of the product. The addition of olive oil alginate emulsion and inulin, O-I 6%, resulted in a low-salt, reduced-fat product (20% less fat than traditional sausage), richer in monounsaturated fatty acids (10%), while retaining sensory notes similar to those of the traditional chorizo used as a control and achieved a good acceptability rating.

Effect of weight at slaughter on the volatile compounds of cooked beef from Spanish cattle breeds

The volatile compounds in cooked beef from the local Spanish cattle breeds, Asturiana, Avileña, Parda Alpina, Pirenaica, Retinta, Rubia Gallega, and Morucha, were studied. Bulls were slaughtered at a live weight of 300 and 550kg and the beef was aged for seven days before cooking. Differences in volatile composition among the breeds were considerable and may contribute to the perception of flavour differences in the cooked beef. Peak area values for dimethyl sulfide, which could be related to cauliflower notes, were highest for the meat from the Pirenaica breed. Levels of the detected volatiles, especially sulfur compounds, in the beef from the Asturiana breed were low-intermediate and were potentially related to blood and liver notes and unpleasant flavours. Avileña stood out among the rustic breeds because of its high values for 1-octene, methylcyclohexane, tetradecane and carbon disulfide, while Retinta displayed high 2,3,4-trimethylpentane levels. The effect of weight at slaughter was influenced by breed, because, except for octane, all the volatile compounds behaved differently according to the breed. Ethanol was characteristic of animals with a high percentage intramuscular fat content, and carbon disulfide was characteristic of animals slaughtered at the lower of the two live weights considered.

The relationship of carcass measurements to carcass composition and intramuscular fat in Spanish beef.

Forty beef carcasses were classified for conformation and fatness. Besides, carcass weight, fat thickness (FT), carcass dimension, marbling by computer image analysis and ultrasound readings was recorded to complement grading. For predicting intramuscular fat (IMF) content, FT, number of intramuscular flecks and conformation increased R(2)-value from 0.19 to 0.64 compared to conformation alone. For visual marbling, ultrasound readings and thoracic depth (TD) increased the R(2)-value from 0.24 to 0.57 compared to fatness score (FS). The best variables for predicting weight of fabricated subprimals were carcass weight or compactness which is a function of carcass weight (R(2) between 0.94 and 0.63). Fatness score was poorer than FT for predicting yield of subprimals cuts from round (R(2)=0.16 vs. 0.50) and ultrasound readings for less valuable subprimals (R(2)=0.31 vs. 0.39). These results showed that other variables could be used in combination with carcass fatness or conformation to achieve a more accurate estimation of fat and carcass yield.

Predicting Longissimus dorsi myoglobin oxidation in aged beef based on early post-mortem colour measurements on the carcass as a colour stability index

Sixty young bulls of the Pirenaica breed, representative of the beef production and marketing system in northern Spain, were used. The carcass grading and weight, pH at 24h post-mortem, and objective colour measurements (CIE L(∗)a(∗)b(∗)) were recorded on the Latissimus dorsi, Rectus abdominis and Longissimus dorsi in order to find indicators and predictors of beef colour stability (Longissimus dorsi metmyoglobin percentage on ageing for 3, 7 and 14days) by means of early post-mortem measurements on the carcass. Neither the conformation nor the degree of fattening, under the current EU beef carcass classification system, displayed any statistically significant relationship with colour stability of beef aged 3, 7 and 14days. However, there was a relationship between the instrumental colour measured on the carcass and the colour stability of the beef. This relationship allowed prediction of colour stability (Longissimus dorsi MMb percentage) after 3, 7 and 14days of ageing and 48h blooming using colour coordinates measured on the carcass.

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.

Predicting longissimus dorsi texture characteristics in beef based on early post-mortem colour measurements.

Sixty young bulls of Pirenaica breed that were representative of the beef production and marketing systems in Northern Spain were studied. The following parameters were determined with the aim of predicting beef texture characteristics of the longissimus dorsi based on the objective measurements taken on the carcass at the early post-mortem period: colour measurement (CIE L(∗)a(∗)b(∗)) readings were taken on the latissimus dorsi (LTD), rectus abdominis (RA), and longissimus dorsi (LD) muscles. In this study, it was observed that more information on beef tenderness is obtained with colour measurements taken on the carcass LTD and RA, and LD at 24h post-mortem. However, the regression analysis showed that beef TI from Pireanica young bulls can be predicted quite accurately by C(∗) measured on the RA muscle just 45min after slaughter.

Effect of whole linseed and rumen-protected conjugated linoleic acid enriched diets on feedlot performance, carcass characteristics, and adipose tissue development in young Holstein bulls

Forty-eight young Holstein bulls (slaughtered at 458.6±9.79 kg body weight) were used to evaluate the effect of whole linseed and conjugated linoleic acid (CLA) supplementation on animal performance, adipose tissue development, and carcass characteristics. The animals were fed with one of four isoenergetic and isoproteic diets: control (0% linseed, 0% CLA), linseed (10% linseed, 0% CLA), CLA (0% linseed, 2% CLA), and linseed plus CLA (10% linseed, 2% CLA). Animal performance and carcass characteristics were unaffected by diet composition. Adding linseed or CLA to the concentrate diet did not result in significant differences in adipocyte size and number or lipogenic enzyme activity. However, while the frequency distribution of subcutaneous adipocyte diameters followed a normal distribution, the frequency distribution of intramuscular adipocyte diameters was not normal in any dietary group (skewness coefficients: 0.8, 1.2, 0.9, 0.8 for control, linseed, CLA, and linseed plus CLA, respectively; P<0.05), indicative of adipocyte proliferation in the intramuscular adipose tissue.

Effects of Addition of Linseed and Marine Algae to the Diet on Adipose Tissue Development, Fatty Acid Profile, Lipogenic Gene Expression, and Meat Quality in Lambs

This study examined the effect of linseed and algae on growth and carcass parameters, adipocyte cellularity, fatty acid profile and meat quality and gene expression in subcutaneous and intramuscular adipose tissues (AT) in lambs. After weaning, 33 lambs were fed three diets up to 26.7 ± 0.3 kg: Control diet (barley and soybean); L diet (barley, soybean and 10% linseed) and L-A diet (barley, soybean, 5% linseed and 3.89% algae). Lambs fed L-A diet showed lower average daily gain and greater slaughter age compared to Control and L (P < 0.001). Carcass traits were not affected by L and L-A diets, but a trend towards greater adipocyte diameter was observed in L and L-A in the subcutaneous AT (P = 0.057). Adding either linseed or linseed and algae increased α-linolenic acid and eicosapentaenoic acid contents in both AT (P < 0.001); however, docosahexaenoic acid was increased by L-A (P < 0.001). The n-6/n-3 ratio decreased in L and L-A (P < 0.001). Algae had adverse effects on meat quality, with greater lipid oxidation and reduced ratings for odor and flavor. The expression of lipogenic genes was downregulated in the subcutaneous AT (P < 0.05): acetyl-CoA carboxylase 1 (ACACA) in L and L-A and lipoprotein lipase (LPL) and stearoyl-CoA desaturase (SCD) in L-A. Fatty acid desaturase 1 (FADS1), fatty acid desaturase 2 (FADS2) and fatty acid elongase 5 (ELOVL5) were unaffected. In the subcutaneous AT, supplementing either L or L-A increased peroxisome proliferator-activated receptor gamma (PPARG) and CAAT-enhancer binding protein alpha (CEBPA) (P < 0.05), although it had no effect on sterol regulatory element-binding factor 1 (SREBF1). In the intramuscular AT, expression of ACACA, SCD, FADS1 and FADS2 decreased in L and L-A (P < 0.001) and LPL in L (P < 0.01), but PPARG, CEBPA and SREBF1 were unaffected.