Evaluation of different bovine muscles to be applied in freeze-drying for instant meal. Study of physicochemical and senescence parameters.

The aim of the present research was to evaluate bovine muscles to be subjected to freeze-drying for an instant meal. Physicochemical and senescence parameters were evaluated. The experimental part was divided into two steps. In the first step, the Semitendinosus muscle was chosen to establish methodology and experimental conditions. Physicochemical, microstructure and senescence parameters were analysed. In the second step, economic bovine muscles such as Semimembranous and Spinalis dorsi were subjected to the same methodology and conditions as in the first step in order to compare them by analysing the same parameters. L* and a* values were statistically significant (P<0.05) for Semimembranous and Spinalis dorsi muscles, showing differences among condition effects and in muscles. Humidity and water activity showed among the muscles analysed that cooked and rehydrated samples did not exhibit differences. Microstructure of Semitendinosus and Semimembranous were not separated and fragmented as occurred with Spinalis dorsi after freeze-drying. Results allowed us to select among the muscles studied that Semimembranous was suitable and economic to be used in an instant meal.

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 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.

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.

Oxidative stability and its relationship with natural antioxidants during refrigerated retail display of beef produced in Argentina.

The objective of this study was to determine if pasture or grain diets affect oxidative/antioxidative status and the color stability of beef during retail display. Ten crossbreed steers were fed on pasture. Five of them were randomly assigned to remain on this diet, and the other five were finished on feedlot system (grain diet) during 110days until slaughter. Slices of Psoas major steaks were randomly distributed among retail display times (1, 3, 5, 7 and 9days). Lipid and protein oxidation were higher in Psoas major steaks from grain diet than in pasture diet (P<0.05). After 3days of display, lipid oxidation increased in meat from grain diet, whereas in meat from pasture diet the first evidence was after 7days (P<0.05). Protein oxidation was higher in meat from grain diet than in meat from pasture diet at day 9 of display (1.15±0.92 vs. 1.91±0.70µg/g, respectively; P<0.05). Antioxidant vitamins, α-tocopherol and ß-carotene were higher at time=0 in pasture Psoas major steaks (P<0.05) and were differentially reduced throughout storage. While α-tocopherol decreased 41% and 57% for pasture and grain beef respectively (P<0.05), ß-carotene levels remained practically unaffected in grain beef. After 7days of display "a" value was higher for Psoas major steaks from pasture diet (P<0.05). Besides, "L" parameter showed higher values for samples from grain diets but it was no affected by display time. No differences were observed between both treatments for "b" value, but a significant decrease (P<0.05) was observed along storage. Superoxide dismutase and catalase activity was stable throughout storage, while glutathione peroxidase activity decreased significantly (P<0.05). The results in this study demonstrated that the higher initial level and synergistic action (under light and air) of α-tocopherol and ß-carotene found in pasture-finished animals improved the oxidative and color stability of beef, as showed by a better retention of redness at the end of retail display.

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.

Effect of whey protein concentrate and sodium chloride concentrations on the odour profile of sous vide cooked whole-muscle beef from Argentina.

Semitendinosus muscles added with whey protein concentrate (WPC) and sodium chloride (NaCl) were submitted to sous vide cooking. Four enhancement treatments and a control were tested: 0.875% WPC (w/w)+0.625% NaCl, 2.625% WPC+0.625% NaCl, 0.875% WPC+1.875% NaCl, 2.625% WPC+1.875% NaCl, and control (non-injected muscles). Odour analyses were carried out with an electronic nose (EN) system. EN data were evaluated applying Principal Component Analysis, Linear Discriminant Analysis and Partial Least Squares algorithm. EN was able to discriminate the odour profiles of cooked enhanced beef as a function of the amount of WPC added. No significant differences in odour profiles were observed regarding NaCl concentration. These results agreed with those obtained when odour profiles were analysed in WPC dispersions. The reported results support the applicability of EN methodology for analysing the impact of processing parameters on beef odour profiles.

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.

Antioxidant status and odour profile in fresh beef from pasture or grain-fed cattle.

The main goal of the present work was to determine the overall antioxidant status in fresh meat from animals fed different diets and to differentiate them through their odour profiles. Attributes were evaluated in beef from pasture or grain-fed animals with (PE and GE) or without supplementation (P and G) with vitamin E (500UI/head/day). Fresh meat produced on pasture (P and PE) had higher total ferric reducing antioxidant power (FRAP) levels than meat from grain fed-animals (G and GE) (P<0.05). However, no differences were found on their ability to reduce ABTS(+) (2,2'-azino-bis-(3-ethylbenz-thiazoline-6-sulfonic acid)), indicating that total antioxidant activity was preferentially due to the reduction potential than to the quenching capacity of tissue homogenates. Two-fold glutathione (GSH and GSSG are the reduced and oxidised forms, respectively) levels were found in the P+PE group respect to G+GE meat (P<0.001). In addition, meat from pasture-fed animals presented a higher glutathione redox potential compared to grain-fed animals (-156.1±6.1 and -158.1±6.5 vs. -148.1±13 and -149.8±14.6 for P, PE G and GE, respectively), showing that the antioxidant status in fresh meat was affected by diet. Enzymatic activity of catalase and glutathione peroxidase were equivalent for all dietary groups. Only superoxide dismutase activity was slightly higher (P<0.05) in the P+PE group than in G+GE samples. Odour profile analysis was performed in relationship to antioxidant parameters. Significant linear correlation coefficients (P<0.05) were found for a set of sensors and the FRAP values. E-nose methodology successfully discriminated the odour characteristics of samples corresponding to pasture- or grain-based diet. Hence, it was possible to describe an analytical relationship between the odour profile and the antioxidant power of fresh meat.

Warmed-over flavour analysis in low temperature-long time processed meat by an "electronic nose".

The ability of an electronic nose, comprising 32 conducting polymer sensors, to identify and classify warmed-over flavour (WOF) aroma in bovine semitendinosus muscle, processed by vacuum cook-in-bag/tray technology (VCT) and storage under refrigerated conditions, was evaluated. The VCT process employed low temperature-long time (50°C-390 min) thermal treatments. Multivariate analysis showed that VCT processed beef aroma profiles were sorted into two groups, one included samples stored for up to 20 days and the other included samples with 34 to 45 days of storage. WOF odour standard samples were recognised to have similar aroma as samples of the second group. Lipid oxidation results, measured by thiobarbituric acid reactive substances, showed an increment in oxidation level for samples stored for 34 days or more (P<0.05). This study shows that electronic nose technology can be applied to WOF odour identification and classification in VCT beef meat, complementing chemical and sensory techniques used in this field.

Anticorpos monoclonais no estudo da matriz extracelular nas patologias mamárias / Monoclonal antibodies in the study of extracellular matrix in breast pathologies

O estudo da arquitetura ne dos componentes da matriz extracelular das patologias benignas e malignas da mama pode ser a base para o conhecimento dos processos biológicos normais e patológicos. Lesöes proliferativas benignas da mama de 38 mulheres, 10 casos de carcinomas in situ e 20 casos de carcinoma invasivo foram estudados com uma técnica imuno-histoquímica usando anticorpos monoclonais contra componentes da matriz extracelular, colágeno III e IV, laminina e fibronectina. Os resultados mostraram: (a) os componentes da matriz extracelular variam qualitativamente e quantitativamente nas diferentes patologias mamárias; (b) ausência de uma membrana basal contínua no carcinoma invasor; (c) presença de membrana basal no carcinoma pré-invasor