zsakdk

Influencia del perfil de ácidos grasos de la leche de
oveja sobre la calidad del yogur firme, evaluado a lo
largo de la vida útil



diferencias detectadas en las propiedades físicas son debidas a la modificación del
perfil lipídico de la grasa de la leche. El análisis microbiológico mostró que no existen
diferencias significativas en el recuento de Streptococcus thermophilus entre L0 yL1,
pero sí se vieron diferencias en el recuento de Lactobacillus bulgaricus siendo los
recuentos en L1 menores a los de L0 a lo largo del tiempo. Finalmente el análisis
sensorial descriptivo mostró diferencias significativas únicamente en la intensidad del
olor y el aroma a nata, siendo calificado L1 con mayor intensidad de olor a día 14 y 28,
pero con menor aroma a nata que L0.
Palabrasclave: Yogur, Oveja, Vida útil, Ácidos grasos, Calidad

4

Influencia del perfil de ácidos grasos de la leche de oveja sobre la calidad del yogur firme,
evaluado a lo largo de la vida útil

2014

Abstract
The objective of this work was to study the significant differences, as for characteristics
and the quality parameters of firm yogurt using as sheep milk raw material with
modified fatacid profile (L1), which highest proportion of monounsaturated fatty acids
(MUFA) and lower saturated fatty acid (SFA), with regard to the normal composition of
sheep milk (L0). These differences were evaluated as for along shelf-life time (days 1,
14 and 28). With the analysis of the data obtained it has been noted that variables
representing the color (L*, a*) at L1 decreased significantlywhile b* value increased.
Regarding the apparent viscosity is observed that L1 increased along the shelf-life time
and was significantly lower than L0 throughout the storage time. The analysis of texture
showed that the firmness was no significant difference between L0 and L1, but they
were differences as for consistency and cohesiveness, was being L1 less consistency
at day 1 and lowercohesiveness at day 1, 14 and 28 than L0. The physicochemical
analysis showed significant differences in pH with respect to shelf-life at day 28, being
L1 less acidic than L0; which is related to the higher percentage of lactose in L1 at day
28; as for composition (ash, fat, drymatter and protein) did not showed significantly
differences at day 1 of the manufacturing between L0 and L1, this showsthat the
differences detected in the physical properties are due to lipid profile modified of fat
milk. The microbiological analysis showed no significant differences in the count
Streptococcus thermophilus between L0 and L1, but they were differences in the count
of Lactobacillus bulgaricus being L1 lower than L0 during the storage time. Finally the
descriptive sensory analysis showedsignificant differences only in Intensity of the smell
and the aroma of cream, being more qualified L1 with more Intensity of the smell at day
14 and 28, but less aroma of cream than L0.
Keywords: Yogurt, sheep, shelf-Life, fatty acids, quality.

5

Influencia del perfil de ácidos grasos de la leche de oveja sobre la calidad del yogur firme,
evaluado a lo largo de la vida útil

2014

1Introducción
La leche de oveja tiene un contenido de materia grasa y proteína mayor que el
de la leche de cabra y de vaca. El elevado contenido de proteínas y el contenido sólido
general de la leche de oveja hace que sea particularmente adecuada para la
producción de quesos y yogur. La producción de leche de oveja es importante en la
región del Mediterráneo, empleándose en su mayor parte para laelaboración de queso
(FAO, 2014), principalmente en países como Francia, Italia, España y Grecia (Park &
Haenlein, 2006). En España, Castilla y León es una zona geográfica importante en la
producción de leche, siendo actualmente la principal productora de leche de oveja, ya
que produce un 66% del total nacional y, al mismo tiempo, es la segunda productora
de leche de vaca tras Galicia...