Genetic and management factors affecting beef quality in grazing Hereford steers.

Attributes contributing to differences in beef quality of 206 Hereford steers finished on pasture were assessed. Beef quality traits evaluated were: Warner-Bratzler meat tenderness and muscle and fat color at one and seven days after slaughter and trained sensory panel traits (tenderness, juiciness, flavor, and marbling) at seven days. Molecular markers were CAPN1 316 and an SNP in exon 2 on the leptin gene (E2FB). Average daily live weight gain, ultrasound monthly backfat thickness gain and rib-eye area gain were estimated. Molecular markers effects on meat quality traits were analyzed by mixed models. Association of meat quality with post weaning growth traits was analyzed by canonical correlations. Muscle color and marbling were affected by CAPN1 316 and E2FB and Warner-Bratzler meat tenderness by the former. The results confirm that marker assisted selection for tenderness is advisable only when beef aging is a common practice. The most important sources of variation in tenderness and color of meat remained unaccounted for.

Effect of feeding treatment during the backgrounding phase of beef production from pasture on: I. Animal performance, carcass and meat quality.

This research evaluated effects of feedlot backgrounding on 40, 70 or 100% alfalfa hay diets (40 hay, 70 hay; 100 hay, respectively) or pasture grazing (Pasture) before pasture finishing, on performance and beef characteristics of Angus heifers. Ninety six female calves were allocated to the four feeding strategies. Backgrounding took place during 114 days and subsequent pasture finishing over 132 days. Heifers of each strategy were slaughtered after 114 days (end of the feedlot period) and at end of the study when all remaining animals were finished on pasture. Effects of backgrounding were associated with rate of gain. Backgrounding strategies 40 hay and Pasture resulted in the best performance. Beef attributes were similar. At the end of the feedlot period, 100 hay was smaller and leaner, less tender and less juicy. At the end of the study, Pasture and 40 hay heifers had on average the largest back fat thickness and intramuscular fat measurements. No treatment effects were detected for Warner-Bratzler shear force, muscle pH, muscle color and sensory panel attributes.

Effect of the addition of conventional additives and whey proteins concentrates on technological parameters, physicochemical properties, microstructure and sensory attributes of sous vide cooked beef muscles.

Beef muscles submitted to four enhancement treatments (1.88% whey protein concentrate (WPC)+1.25% sodium chloride (NaCl); 1.88% modified whey protein concentrate (MWPC)+1.25%NaCl; 0.25% sodium tripolyphosphate (STPP)+1.25%NaCl; 1.25%NaCl) and a control treatment (non-injected muscles) were sous vide cooked. Muscles with STPP+NaCl presented a significantly higher total yield (106.5%) in comparison to those with WPC/MWPC+NaCl (94.7% and 92.9%, respectively), NaCl alone (84.8%) or controls (72.1%). Muscles with STPP+NaCl presented significantly lower shear force values than control ones; also, WPC/MWPC+NaCl added muscles presented similar values than those from the other treatments. After cooking, muscles with STPP+NaCl or WPC/MWPC+NaCl depicted compacted and uniform microstructures. Muscles with STPP+NaCl showed a pink colour, meanwhile other treatment muscles presented colours between pinkish-grey and grey-brown. STPP+NaCl added samples presented the highest values of global tenderness and juiciness. The addition of STPP+NaCl had a better performance than WPC/MWPC+NaCl. However, the addition of WPC/MWPC+NaCl improved total yield in comparison to NaCl added or control ones.

Protective action of Lactobacillus curvatus CRL705 on vacuum-packaged raw beef. Effect on sensory and structural characteristics.

Lactobacillus curvatus CRL705 was examined for its effectiveness as protective culture in the biopreservation of vacuum-packaged fresh beef stored during 60 days at 2 degrees C. For this purpose, L. curvatus CRL705, producer of lactocin 705 and lactocin AL705, was inoculated on the meat surface (10(6)cfu g(-1)). This microorganism became the dominating population throughout the storage period controlling the growth of Brochothrix thermosphacta and spoilage lactic acid bacteria naturally present on the meat. When the microstructural characteristics of the meat were evaluated using light microscopy, beef samples inoculated with the bioprotective culture showed a 10days delay for the appearance of tissue degradation signs. Sensory analysis demonstrated that beef samples treated with L. curvatus CRL705 only developed an "acid" off-flavor after 60 days of refrigerated storage, and no undesirable off-odors were found. Therefore, inoculation with this bacteriocinogenic strain would provide an additional hurdle to improve storage life of refrigerated vacuum-packaged beef without affecting its sensory and structural characteristics.

Meat quality traits of commercial hybrid pigs in Argentina.

This report describes the meat quality of two INTA hybrids (hybrid females) sired by Duroc (D) or Yorkshire (Y) boars and a third one from PIC (S), a cross of females C22 to 412 boars. Starting at 30kg live weight, 18 barrows and 18 gilts of each genotype were kept in identical conditions until slaughtered at 110kg. Longissimus dorsi muscles were analyzed. Means differed significantly (P<0.05) for drip loss (higher in S); tenderness (more tender in D), water holding capacity (higher in Y); cooking loss (higher in Y); colour parameter L(∗) (lower in D) and b(∗) (higher in S) and intramuscular fat content (higher in D). As a result of sensory analysis, it was found that D was the most tender and juicy. There were few sex effects and no genotype-sex interactions. Distinct differences in meat quality between hybrids do exist, with D superior, S the worst, and Y intermediate.

Diet and genotype effects on the quality index of beef produced in the Argentine Pampeana region.

Steers of varying genotypes (Aberdeen Angus, Charolais x AA and Argentine Holstein) in four feeding systems were evaluated. Feeding systems were: S1=a diet based on pastures only; S2=a similar forage base as S1 plus a daily supplementation with cracked corn, at 0.7% of l.w./head/day; S3=a similar forage base as S1 plus a daily supplementation with cracked corn, at 1.0% of l.w./head/day; and S4=a regular feedlot diet. Tenderness and marbling were not affected by the feeding system. Feedlot meat showed an n-6/n-3 ratio significantly higher than meat produced with the diets based on pastures (S1=2.1; S2=3.1; S3=4.5; S4=14.2) (P<0.05), whereas CLA content had an inverse behavior, showing S1 (0.67%) and S2 (0.64%) higher concentrations than S3 (0.55%) and S4 (0.28%) (P<0.05). Diet based on pastures plus a low level of supplementation produced meat with better nutritional characteristics than other productive alternatives, without significant effects of the biotypes.

Optimization of whey protein concentrate and sodium chloride concentrations and cooking temperature of sous vide cooked whole-muscle beef from Argentina.

Response surface methodology was used to optimize the effect of cooking temperature (CT: 65-75°C) and the incorporation of whey protein concentrate (WPC: 0-3.5%) and sodium chloride (NaCl: 0-2.5%) on technological, physical and sensory characteristics of cooked whole-muscle beef. Post-injection weight loss diminished when NaCl concentration increased. Moreover, the increment of both additives produced a reduction of cooking loss. An opposite effect was observed with the increment of CT. As it was expected, a total yield improvement was achieved by increasing both ingredients and diminishing CT. Equivalent yields are achieved complementing both ingredients, meaning that if one ingredient concentration is reduced the other has to be increased. Shear force values were not affected by the studied factors. Instead, lightness was reduced by their increment. At 65°C, injected muscles had lower flavour and odour scores than control. At all CT analyzed, the incorporated brines improved juiciness and tenderness-related attributes. Present results recommend the use of a CT of 70°C and maxima WPC and NaCl concentrations of 2.6% and 1.9%, respectively.

Antioxidant consumption and development of oxidation during ageing of buffalo meat produced in Argentina.

Buffalo meat production is increasing in Argentina. Information on meat quality and nutritional value will be useful in marketing. This work describes the oxidative stability of the Longissimus dorsi (LD) in relation to consumption of antioxidant vitamins, fatty acid composition and color deterioration during ageing. Vitamins levels found in fresh beef were 4.22±0.93; 0.24±0.05 and 0.25±0.06µg/g for α- and γ-tocopherol, and ß-carotene, respectively. Vitamin loss was almost 90% throughout an ageing period of 25 days at 2°C. Concomitantly, TBARS levels increased from 0.076±0.018 to 0.14 6±0.032mg MDA/kg beef. Hexanal and pentanal levels were low and no correlations with oxidation were detected (P>0.05). The predominant color changes in aged beef were reduced redness and yellowness with an increase in lightness (P<0.05). Vitamin levels and TBARS were used to develop a prediction equation for post-mortem aging.

Effect of whey protein concentrate and sodium chloride addition plus tumbling procedures on technological parameters, physical properties and visual appearance of sous vide cooked beef.

Beef muscles cooked by the sous vide system were evaluated for the effects of pre-injection tumbling, brine addition and post-injection tumbling on technological parameters, physical properties, visual appearance and tissue microstructure. The muscles were injected at 120% (over original weight) with a brine formulated to give a concentration of 3.5% whey protein concentrate and 0.7% sodium chloride on an injected raw product basis. Pre-injection tumbling did not affect most of the evaluated parameters. Brine addition reduced significantly the cooking and total weight losses. Total weight loss was 7.2% for injected muscles, and significantly higher (28.2%) for non-injected ones. Brine incorporation increased pH and reduced shear force values of cooked muscles. Extended post-injection tumbling (5rpm-10h) improved brine distribution and visual appearance, and also diminished the shear force values of cooked muscles. However, this treatment increased the weight losses of post-injection tumbling and cooking-pasteurization stages.

Effect of calcium chloride marination on bovine Cutaneus trunci muscle.

The aim of this investigation was to determine the possibility of using calcium chloride solution in tough muscles (Cutaneus trunci) to reduce the aging period required to increase tenderness, without introducing undesirable flavors. Muscles were marinated in 0.25 M CaCl(2) solution for 2 h and after that aged for 0, 1, 2, 3, 4, 5 and 7 days. Tenderness was evaluated by the myofibrillar fragmentation index (MFI), Warner Bratzler shear force (WBS) and sensory panel evaluation. MFI values showed significant differences between treated and control samples aged for 1, 2 and 3 days (P<0.05). MFI values of treated samples aged 3 days were similar to those obtained for the control samples but aged seven days. WBS values were not significantly different between samples. Consumer panelists preferred treated samples aged 3 days to the control ones aged 7 days. It was concluded that calcium chloride treatment can be used in Cutaneus trunci muscle to reduce the aging time required to increase tenderness.