The aim of this study was to evaluate production performance, carcass characteristics and nutritive value of meat of rabbits reared under the 2 prevailing feeding strategies in Uruguay. One week after weaning, 96 purebred V line rabbits were randomly distributed between 2 treatments: (T1) commercial pelleted food ad libitum and (T2) commercial pelleted food ad libitum plus fresh alfalfa ad libitum. Each treatment included 12 cages containing 4 individuals each (2 males and 2 females). Growth performance characteristics (live weight evolution, commercial food consumption and food/gain ratio) were evaluated. The consumption of alfalfa was not measured. Rabbits were slaughtered at a live weight of 2500 g and carcass characteristics were evaluated. Samples of meat and dissectible fat were analysed to determine intramuscular fat content at muscle L. dorsi, dissectible fat and intramuscular fat composition, minerals (Zn, Fe, Mg and Na), vitamin E and purines. Sensory evaluations were conducted to assess the effect of treatments on the consumer's perception of differences and the existence of attributes determining preferences. Differences between treatments were significant for total commercial food intake (23 356 vs. 20 930 g/cage; P<0.001) and feed conversion ratio (3.82 vs. 3.41; P<0.01) for T1 and T2 respectively. No significant differences were found in average daily gain, age at slaughter and carcass characteristics. There were no significant differences in the intramuscular fat content. The fatty acid composition of dissectible and intramuscular fat was affected by the inclusion of alfalfa in the diet increasing the linolenic acid content (1.82 vs. 3.28% and 2.29 vs. 5.15% for T1 and T2 at intramuscular and dissectible fat, respectively; P<0.001), and improving the n-6/n-3 relationship (8.60 vs. 5.82 and 11.58 vs. 5.64 for T1 and T2 at intramuscular and dissectible fat, respectively; P<0.001). There were no significant differences in vitamin E, Fe or Zn content between treatments, but differences were significant in Mg (22.5 vs. 24.4 mg/100 g for T1 and T2; P<0.05) and Na (44.1 vs. 48.2 mg/100 g; P<0.05). In the sensory evaluation, panellists significantly perceived differences between treatments with 95% confidence.

High-pressure homogenization (HPH) of milk was studied as an alternative processing operation in the manufacturing of queso fresco cheese. Raw and pasteurized (65°C for 30 min) milks were subjected to HPH at 0, 100, 200, and 300 MPa and then used to manufacture queso fresco. The cheeses were evaluated for yield, moisture content, titratable acidity, nitrogen content, whey protein content, yield force, yield strain, and tactile texture by instrumental or trained panel analyses. The combination of HPH and thermal processing of milk resulted in cheeses with increased yield and moisture content. The net amount of protein transferred to the cheese per kilogram of milk remained constant for all treatments except raw milk processed at 300 MPa. The highest cheese yield, moisture content, and crumbliness were obtained for thermally processed milk subjected to HPH at 300 MPa. The principal component analysis of all measured variables showed that the variables yield, moisture content, and crumbliness were strongly correlated to each other and negatively correlated to the variables yield strain, protein content (wet basis), and sensory cohesiveness. It is suggested that the combination of thermal processing and HPH promotes thermally induced denaturation of whey protein, together with homogenization-induced dissociation of casein micelles. The combined effect results in queso fresco containing a thin casein-whey matrix that is able to better retain sweet whey. These results indicate that HPH has a strong potential for the manufacture of queso fresco with excellent yield and textural properties.

No abstract

El queso Colonia es un queso típico uruguayo, elaborado según los criterios de calidad y tradición quesera de inmigrantes suizos radicados en el departamento de Colonia. Su investigación y publicación aportan conocimiento para la difusión de un proceso que aún no presenta denominación de origen protegida. El objetivo del estudio fue investigar si la tecnología de salado por impregnación en vacío afecta el proceso de maduración del queso Colonia en comparación con el proceso de salado tradicional. Para el seguimiento de los cambios se realizaron determinaciones del índice de maduración, concentración del cloruro de sodio en agua del queso, el pH y la evolución de las bacterias Lactococcus lactis, Lactococcus lactis subsp. diacetylactis, Leuconostoc subsp. mesenteroides y Propionibacterium. Al ¿ nalizar la maduración, se evaluaron sensorialmente los atributos de textura, sabor y aroma, apariencia externa y apariencia interna. Las condiciones operativas elegidas del salado por impregnación en vacío lograron el mismo ingreso de sal que las del proceso tradicional y en la mitad del tiempo. No se observaron diferencias en ninguno de los parámetros químicos y microbiológicos estudiados. En lo sensorial tampoco se apreciaron diferencias en el À avor, textura y apariencia externa. Se hallaron ciertas diferencias en el tamaño y distribución de los ojos. Palabras clave: Tiempo de salado, bacterias lácticas, bacterias propiónicas, queso uruguayo.Abstract "Colonia" type cheese is a typical Uruguayan cheese, elaborated following the quality standards and cheese making tradition brought by Swiss immigrants settled down at the Uruguayan department of Colonia. Its study and outreach provide knowledge to the diffusion of a process wich does not present a protected designation of origin. The aim of the study was to analize if the vacuum impregnation technology affects Colonia cheese ripening process compared with the traditional salting methods. Chemical, microbiological and sensory changes during ripening after both, SIV and traditional salting methods, were analized in this study. Chemical changes refer to moisture, sodium chloride concentration and rate of ripening. The microbiological changes were focused onto bacteria growing and identi¿ cation of Lactococcus lactis, Lactococcus lactis subsp diacetylactis, Leuconostoc subsp mesenteroides and Propionic bacteria. Sensory attributes linked to texture, taste and À avor, as much as external and internal appearances were evaluated. The selected operating conditions of the vacuum impregnation process allowed the income ingress of salt to the cheese in half traditional process time. Under these conditions, no differences in chemical and microbiological parameters studied were appreciated. There were no sensory differences in À avor, texture and the outward appearance but certain differences in the size and distribution of the eyes were found.

La dieta animal es uno de los factores que más incide sobre la calidad de los productos porcinos. En este trabajo se evaluó el efecto de la utilización de semilla de girasol de alto oleico (SGAO) y pasturas sobre la calidad química y sensorial del jamón curado. Se analizaron jamones provenientes de 60 cerdos faenados a los 145 kg. Éstos fueron sometidos a cuatro tratamientos, consistentes en el suministro de dietas con diferente aporte lipídico en cantidad y composición química, con y sin acceso a pasturas: i) ración estándar, sin pasturas; ii) ración estándar, con pasturas; iii) ración con SGAO, sin pasturas, y iv) ración con SGAO, con pasturas. Se evaluaron parámetros físico-químicos y sensoriales de jamones obtenidos luego de un curado tradicional de nueve meses. La ración con SGAO dio lugar a jamones con una mayor proporción de C18:1(Ȧ9) y menor de ácidos grasos saturados en relación a la estándar. Las pasturas incidieron sobre el color y determinaron una mayor proporción de C18:3(Ȧ3) y C22:6(Ȧ3). Se concluye que con una dieta compuesta por SGAO y pasturas se obtienen jamones con mayor proporción de ácidos grasos oleico y Ȧ3 y relaciones Ȧ6/Ȧ3 más favorables para la salud humana, sin que se vean afectados atributos sensoriales.