Impact of a constant current electrical stimulation (CCES) system and hormonal growth-promoting (HGP) implants on meat quality and palatability of finished steers.

This study evaluated the effects of a constant current electrical stimulation (CCES) system and hormonal growth-promoting (HGP) implants on the quality and palatability of the longissimus thoracis et lumborum (LTL) from yearling-finished steers. The experiment used a total of 46 Angus cross steers, which were either non-implanted (n = 20) or implanted with trenbolone acetate and estradiol benzoate (n = 26). The CCES was applied to one side of each carcass during the slaughter process, whereas the other side remained unstimulated. Regardless of the application of HGP implants, the CCES reduced pH at 3 and 72 h post-mortem and shear force at all ageing times (P < 0.05), improved colour at 72 h post-mortem and during the retail display (P < 0.05), increased initial and overall tenderness (P < 0.01), and decreased the amount of perceived connective tissue and the proportion of trained panelists detecting spongy texture (P < 0.05) compared to meat from unstimulated carcass sides. Although CCES increased meat purge losses and reduced moisture content (P < 0.05), this did not affect meat juiciness (P > 0.10). CCES interacted with HGP to prevent increase in drip loss (P > 0.10), increase frequency of panelists detecting bloody/serumy flavour and typical texture, and reduce the proportion of panelists detecting rubbery texture in meat (P < 0.05). Regardless of stimulation treatment, meat from implanted animals had a more pronounced pH decline at 72 h post-mortem (P < 0.05) and a higher proportion of panelists finding no off-flavours (P < 0.05) or bloody/serumy flavour (P < 0.01) than non-implanted cattle. The CCES system tested in this study improved LTL quality and palatability of heavier beef carcasses.

Effects of in-the-bag dry-ageing on meat quality, palatability and volatile compounds of low-value beef cuts.

This study evaluated the effects of in-the-bag dry-ageing (BDA) (21 and 42 d) on meat quality, palatability, and volatile compounds of clod heart, brisket, and flat iron cuts from steers. In all cuts, BDA increased moisture losses (P < 0.05), but this did not reduce the juiciness of 21 d BDA versus wet-aged (WA) steaks. In clod heart, BDA increased overall tenderness at 21 d compared to 21 d WA (P < 0.01). Regardless of ageing period, BDA of clod heart increased beef flavour and salty taste and decreased sour-dairy and stale/cardboard flavours and concentrations of volatile compounds derived from lipid oxidation compared to WA (P < 0.05). In brisket, BDA increased salty taste and fatty aroma and reduced bloody/serumy flavour, whereas decreased beef and buttery flavours and intensified some unpleasant aromas/flavours (P < 0.05) for both ageing periods. The BDA of flat iron increased several undesirable aromas/flavours and decreased sweet taste and beef and buttery flavours (P < 0.05), regardless of ageing period. Overall, BDA for 42 d decreased meat quality and palatability and increased concentrations of volatile compounds from lipid oxidation, especially in flat iron cuts. Value could be recovered by customizing BDA periods by cut.

Effect of in-the-bag dry-ageing on meat palatability and volatile compounds of cull cows and youthful steers.

This study evaluated the effects of in-the-bag dry-ageing on eating quality and volatile compounds of longissimus lumborum from cows and steers. Compared to wet-ageing, in-the-bag dry-ageing increased purge loss (P < 0.0001), cooking time (P < 0.0001), salty taste (P < 0.05) and sour-dairy flavour (P < 0.01), whereas decreased cooking loss (P < 0.0001), amount of perceptible connective tissue (P < 0.05) and livery flavour (P < 0.05) in both cow and steer meat. This dry-ageing technology also increased juiciness (P < 0.01) and brown-roasted aroma (P < 0.05) in steer meat, whereas decreased the juiciness (P < 0.01) of cow meat. Regardless of the ageing method, cow meat was tougher (P < 0.0001), less juicy (P < 0.001) and sweeter (P < 0.05) and presented higher amount of perceived connective tissue (P < 0.0001) than steer meat, whereas steer meat had higher ratings for beef (P < 0.05) and brown-roasted (P < 0.01) flavours. Volatile compounds were largely affected (P < 0.05) by animal-type, most of them being higher in cow than steer meat. In contrast, in-the-bag dry-ageing affected a few volatile compounds such as alcohols, aldehydes and ketones.

Characterization and classification of the compositional quality of milk from river buffaloes (Bubalus bubalis) and cows (Bos spp.) in Colombia / Caracterización y clasificación de la calidad composicional de la leche de búfalo (Bubalus bubalis) y de vaca (Bos spp.) en Colombia

ABSTRACT The aim of this study was to classify and characterize the compositional quality of milk from river buffaloes (Bubalus bubalis) and cows (Bos spp.) in Colombia based on the fat, protein, and total solid (TS) contents. Using a hierarchical procedure, data on milk from river buffaloes (n = 7,726) and cows (n = 49,330) were filtered and subjected to cluster analysis in order to generate three groups: Normal (N), High quality (HQ) and Poor Quality (PQ). The categorized database was then randomly separated into two sets (training and validation) and a discriminant analysis was applied. In total, 37.3% of river buffalo milk samples were classified as N (6.80% fat, 4.34% protein, and 16.80% TS), 13% as HQ (9.41% fat, 4.93% protein, and 19.50% TS), and 43.7% as PQ (3.95% fat, 3.92% protein, and 13.7% TS). In contrast, 41.8% of cow milk samples were classified as N (3.64% fat, 3.37% protein, 12.42% TS), 41.2% as PQ (2.71% fat, 3.08% protein, and 10.6% TS), and 16.9% as HQ (5.46% fat, 4.01% protein, and 14.82% TS). The discriminant models for both river buffalo and cow milk were able to classify milk in the N and PQ groups with >90% accuracy, and that in the HQ group with >85% accuracy.

RESUMEN El objetivo de este estudio fue caracterizar y clasificar la calidad composicional de la leche de búfala (Bubalus bubalis) y de vaca (Bos spp.) en Colombia con base en los contenidos de grasa, proteína y sólidos totales. Mediante un procedimiento jerárquico los datos de leche de búfalos de agua (n = 7,726) y vacas (n = 49,330) se filtraron y se sometieron a análisis de conglomerados para generar tres grupos: Normal (N), Alta calidad (HQ) y Calidad deficiente (PQ). La base de datos categorizada se separó aleatoriamente en dos conjuntos (entrenamiento y validación) y se aplicó un análisis discriminante. En total, 37,3% de las muestras de leche de búfalo de agua se clasificaron como N (6,80% de grasa, 4,34% de proteína y 16,80% de TS); 13% como HQ (9,41% de grasa, 4,93% de proteína y 19,50% de TS) y 43,7 % como PQ (3,95% de grasa, 3,92% de proteína y 13,7% de TS). En contraste, el 41,8% de las muestras de leche de vaca se clasificaron como N (3,64% grasa, 3,37% proteína, 12,42% TS); 16,9% como HQ (5,46% de grasa, 4,01% de proteína y 14,82% de TS) y 41,2% como PQ (2,71% grasa, 3,08% proteína y 10,6% TS). Los modelos discriminantes para el búfalo de agua y la leche de vaca fueron capaces de clasificar la leche en los grupos N y PQ con una precisión >90% y en el grupo HQ con >85% de precisión.