Browsing by Author "Guedes, Cristina M."
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- Application of bioelectrical impedance analysis in prediction of light kid carcass and muscle chemical compositionPublication . Silva, Severiano; Afonso, João; Monteiro, António; Morais, Reis; Cabo, Ângelo D.; Batista, Ana Cristina Beviláqua; Guedes, Cristina M.; Teixeira, AlfredoCarcass data were collected from 24 kids (average live weight of 12.5±5.5 kg; range 4.5 to 22.4 kg) of Jarmelista Portuguese native breed, to evaluate bioelectrical impedance analysis (BIA) as a technique for prediction of light kid carcass and muscle chemical composition. Resistance (Rs, Ω) and reactance (Xc, Ω), were measured in the cold carcasses with a single frequency bioelectrical impedance analyzer and, together with impedance (Z, Ω), two electrical volume measurements (VolA and VolB, cm2/Ω), carcass cold weight (CCW), carcass compactness and several carcass linear measurements were fitted as independent variables to predict carcass composition by stepwise regression analysis. The amount of variation explained by VolA and VolB only reached a significant level (P<0.01 and P<0.05, respectively) for muscle weight, moisture, protein and fat-free soft tissue content, even so with low accuracy, with VolA providing the best results (0.326⩽R 2⩽0.366). Quite differently, individual BIA parameters (Rs, Xc and Z) explained a very large amount of variation in dissectible carcass fat weight (0.814⩽R 2⩽0.862; P<0.01). These individual BIA parameters also explained a large amount of variation in subcutaneous and intermuscular fat weights (respectively 0.749⩽R 2⩽0.793 and 0.718⩽R 2⩽0.760; P<0.01), and in muscle chemical fat weight (0.663⩽R 2⩽0.684; P<0.01). Still significant but much lower was the variation in muscle, moisture, protein and fat-free soft tissue weights (0.344⩽R 2⩽0.393; P<0.01) explained by BIA parameters. Still, the best models for estimation of muscle, moisture, protein and fat-free soft tissue weights included Rs in addition to CCW, and accounted for 97.1% to 99.8% (P<0.01) of the variation observed, with CCW by itself accounting for 97.0% to 99.6% (P<0.01) of that variation. Resistance was the only independent variable selected for the best model predicting subcutaneous fat weight. It was also selected for the best models predicting carcass fat weight (combined with carcass length, CL; R 2=0.943; P<0.01) and intermuscular fat weight (combined with CCW; R 2=0.945; P<0.01). The best model predicting muscle chemical fat weight combined CCW and Z, explaining 85.6% (P<0.01) of the variation observed. These results indicate BIA as a useful tool for prediction of light kids' carcass composition.
- Estimativa da composição da carcaça e dos depósitos de gordura de cabritos a partir da medida de gravidade específicaPublication . Cabo, Ângelo D.; Monteiro, António; Teixeira, Alfredo; Guedes, Cristina M.; Santos, V.; Mena, Elisabete; Azevedo, Jorge; Outor-Monteiro, Divanildo; Rodrigues, Sandra; Silva, Severiano
- Evaluation of an image analysis approach to predicting primal cuts and lean in light lamb carcassesPublication . Batista, Ana Catharina; Santos, Virgínia; Afonso, João; Guedes, Cristina M.; Azevedo, Jorge; Teixeira, Alfredo; Silva, SeverianoCarcass dissection is a more accurate method for determining the composition of a carcass; however, it is expensive and time-consuming. Techniques like VIA are of great interest once they are objective and able to determine carcass contents accurately. This study aims to evaluate the accuracy of a flexible VIA system to determine the weight and yield of the commercial value of carcass cuts of light lamb. Photos from 55 lamb carcasses are taken and a total of 21 VIA measurements are assessed. The half-carcasses are divided into six primal cuts, grouped according to their commercial value: high-value (HVC), medium-value (MVC), low-value (LVC) and all of the cuts (AllC). K-folds cross-validation stepwise regression analyses are used to estimate the weights of the cuts in the groups and their lean meat yields. The models used to estimate the weight of AllC, HVC, MVC and LVC show similar results and a k-fold coefficient of determination (k-fold-R2) of 0.99 is achieved for the HVC and AllC predictions. The precision of the weight and yield of the three prediction models varies from low to moderate, with k-fold-R2 results between 0.186 and 0.530, p lt 0.001. The prediction models used to estimate the total lean meat weight are similar and low, with k-fold-R2 results between 0.080 and 0.461, p lt 0.001. The results confirm the ability of the VIA system to estimate the weights of parts and their yields. However, more research is needed on estimating lean meat yield.
- In vivo ultrasound prediction of the fillet volume in senegalese sole (Solea senegalensis)Publication . Afonso, João; Guedes, Cristina M.; Teixeira, Alfredo; Rema, Paulo; Silva, SeverianoSenegalese sole (Solea senegalensis) has been considered a promising new flatfish species for Mediterranean marine fish farming. Accurate prediction of fillet traits in live animals may allow for more efficient control of muscle deposition in fish. In this sense, this study was undertaken to develop a non-invasive method to predict in vivo fish fillet volume and yield using real-time ultrasonography (RTU). The trial was conducted with 44 market weight Senegalese sole (298.54 ± 87.30 g). Fish were scanned with an Aloka SSD 500V with a 7.5 MHz probe. Ten RTU cross-sectional images were taken from the operculum to the caudal fin at regular intervals. These images were analyzed using Fiji software. These data were then used to estimate the partial volumes of the fillet. Actual fillet volume was determined using Archimedes’ principle. Simple and stepwise multiple regression analyses were then used to develop prediction models of fillet volume and yield. The most cranial RTU sections of the fish fillet were the best single predictors of both fillet volume and fillet yield and were the ones included in the best stepwise models. The best RTU slice area explained 82% of the variation observed in fillet volume, but the other RTU slice areas used as predictors of fillet volume showed poor to moderate accuracy (0.035 ≤ R2 ≤ 0.615). Single RTU partial volumes showed poor to very high accuracy (0.395 ≤ R2 ≤ 0.970) as predictors of fillet volume. The best stepwise model based on the RTU slice areas included three independent variables and explained 88.3% of the observed variation. The best stepwise models based on RTU partial volumes (single volumes and/or combinations of single volumes) explained about 97% of the variation observed in fillet volume. Two RTU volume traits, V1–5 + V6–9, and V1+()+9, showed to be practically direct predictors of the actual fillet volume, explaining, respectively, 97% and 96% of the variation observed in the actual fillet volume. The fillet yields show lower correlations with slice areas (r between 0.044 and 0.601) than with volumes (r between 0.288 and 0.637). While further studies are clearly necessary to better understand the potential of RTU for the estimation of fillet yield in fish in general and Senegalese sole in particular, the present results showed that RTU traits can be very good predictors of Senegalese sole’s fillet volume, either used in regression models or as direct predictors.
- Non-destructive imaging and spectroscopic techniques for assessment of carcass and meat quality in sheep and goats: a reviewPublication . Silva, Severiano; Guedes, Cristina M.; Rodrigues, Sandra; Teixeira, AlfredoIn the last decade, there has been a significant development in rapid, non-destructive and non-invasive techniques to evaluate carcass composition and meat quality of meat species. This article aims to review the recent technological advances of non-destructive and non-invasive techniques to provide objective data to evaluate carcass composition and quality traits of sheep and goat meat. We highlight imaging and spectroscopy techniques and practical aspects, such as accuracy, reliability, cost, portability, speed and ease of use. For the imaging techniques, recent improvements in the use of dual-energy X-ray absorptiometry, computed tomography and magnetic resonance imaging to assess sheep and goat carcass and meat quality will be addressed. Optical technologies are gaining importance for monitoring and evaluating the quality and safety of carcasses and meat and, among them, those that deserve more attention are visible and infrared reflectance spectroscopy, hyperspectral imagery and Raman spectroscopy. In this work, advances in research involving these techniques in their application to sheep and goats are presented and discussed. In recent years, there has been substantial investment and research in fast, non-destructive and easy-to-use technology to raise the standards of quality and food safety in all stages of sheep and goat meat production. © 2020 by the authors.
- Prediction of apparent digestibility of hays from natural pastures of the Northeast region of PortugalPublication . Galvão, Lurdes; Guedes, Cristina M.; Rodrigues, M.A.M.; Silva, S.R.; Valentim, Ramiro; Moreira, Olga; Ribeiro, José Ramalho; Sequeira, C.A.In the Northeast region of Portugal hays from natural pastures are traditionally used as the main feed during the period of drought and the evaluation of its nutritive value is essential. The aim of this study was to predict the apparent organic matter digestibility (OMD) of 21 hays from natural pastures based on chemical composition, pepsin-cellulase solubility of organic matter (OMS) and in vitro organic matter digestibility. Chemical composition of hays showed a wide range of values and acid detergent lignin (ADL) was the component that presented the highest variation (CV = 18.4%). The OMD varied between 516 and 658 g/kg OM. The best single OMD predictor was OMS (RSD = 2.8%, R2 = 0.52, P<0.001). Using multiple regression to predict OMD, the variables included in the model were OMS and ADL (OMD = 21.51 + 0.94 OMS – 0.83 ADL; RSD = 2.75%; R2 = 0.54; P<0.0001). According to principal component analysis (PCA) hays were divided in 3 groups and the multiple regression established for the larger group of hays (n=10) was: OMD = 4.13 + 0.85 OMS – 1.03 ADL; RSD = 2.13%, R2 = 0.77, P<0.0001. The OMS method was superior to chemical composition and to the in vitro rumen fluid method in predicting OMD of hays from natural pastures. Results from PCA suggested that it may be useful to group these hays according to its chemical composition to accurately predict OMD.
- Sheep and goat meat processed products quality: a reviewPublication . Teixeira, Alfredo; Silva, Severiano; Guedes, Cristina M.; Rodrigues, SandraEven though sheep and goat processed meat products are not as popular as pork, beef or poultry and are generally considered not as important, they have a very important role in meat consumption around the world. A concise review of the origin and type of the most important sheep and goat processed meat products produced in different countries and world regions is made. The manuscript also summarizes the most recent studies on sheep and goat processed meats on the physicochemical characterizations, sensory quality, microbiological quality and safety. Some conclusions and future trends in production, processing and commercial potentiality for sheep and goat processed meat products are discussed. Several possibilities exist to make them more diversified and appealing to the market. Processing meat from culled animals is an interesting way to value animals with low market acceptability. Some as fermented sausages, cured legs and pâtés have great commercial potential as highly acceptable consumer commodities. An interesting field of food research is the rediscovery of a new generation of goat and sheep meat products as functional foods that will respond to the constant innovation required by the meat industry. Everything related to food safety must be considered in the future.
- Sheep and goat meat processing and qualityPublication . Silva, Severiano; Teixeira, Alfredo; Guedes, Cristina M.Sheep and goat meat production includes the increased demand for grass-fed and organic meat and value-added products such as sausages, meatballs, and burgers. There has also been a growing worldwide interest in ethnic cuisine that uses sheep and goat meat. For example, Mediterranean and Middle Eastern dishes such as lamb kebabs and goat curries can be considered under this scope. There has also been greater interest in diversifying protein sources, including sheep and goat meat, as consumers seek better animal welfare and eco-friendly food choices. Several factors underpin these trends. The reasons for such trends are linked to the physicochemical, sensory, and nutritional properties and long tradition of consuming sheep and goat meat and meat products, such as consuming light carcasses of lambs and goat kids across EU Mediterranean countries, which are commercialized as quality meat brands with protected designation of origin or geographical indication provided. To evaluate and authenticate the origin and quality of sheep and goat meat and its products, non-invasive and non-destructive methods and techniques have gained relevance. These are topics that will be addressed in this Special Issue.
- Sheep whole body composition predicted by in vivo real time ultrasound measurementsPublication . Silva, Severiano; Gomes, Maria José Marques; Teixeira, Alfredo; Guedes, Cristina M.; Santos, V.A.; Azevedo, J.M.T.; Dias-da-Silva, A.Accurate measurement of changes in body composition and in the energy content of live animals is crucial to understand the responses to the intake of nutrients. Despite the accuracy of the serial slaughter technique in determining body composition, it is very expensive and comparisons within an animal became impossible thus the need for an accurate method to predict body composition in the live animal is obvious for the biological efficiency studies. This work aimed to establish equations to estimate in vivo whole empty body chemical composition of sheep using real time ultrasound CRTU) measurements.
- Utilization of bioelectrical impedance to predict intramuscular fat and physicochemical traits of the beef longissimus thoracis et lumborum musclePublication . Afonso, João; Guedes, Cristina M.; Santos, Virgínia; Morais, Raul; Silva, Josa; Teixeira, Alfredo; Silva, SeverianoThe bioelectrical impedance analysis (BIA) is a non-destructive technique that has been successfully used to assess the body and carcass composition of farm species. This study aimed to predict intramuscular fat (IMF) and physicochemical traits in the longissimus thoracis et lumborum muscle (LM) of beef, using BIA. These traits were evaluated in LM samples of 52 crossbred heifer carcasses. The BIA was performed in LM, using a 50 Hz frequency high precision impedance converter system. A correlation analysis of the studied variables was performed. Then a stepwise with a k-folds cross validation procedure was used to modelling the prediction of IMF and physicochemical traits from BIA parameters (24.5%CV47.3%). Wide variation was found for IMF and BIA parameters. In general, correlations of BIA parameters with IMF and physicochemical traits were moderate to high and were similar for all BIA parameters (ô0.50r0.50 only for total pigments, a∗ and pH48). It was possible to predict IMF and physicochemical traits from BIA. The best fit explained 79.3% of the variation in IMF, while for physicochemical traits the best fits were for sarcomere length and shear force (64.4% and 60.5%, respectively). The results confirmed the potential of BIA for objective measurement of meat quality.