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Projecte llegit

Títol: Crioconcentración al vacío de tres tipos de suero de leche de vaca

Estudiant que ha llegit aquest projecte:

Tutor/a o Cotutor/a: HERNANDEZ YAÑEZ, EDUARD

Departament: DEAB

Títol: Crioconcentración al vacío de tres tipos de suero de leche de vaca

Data inici oferta: 03-02-2020      Data finalització oferta: 03-10-2020

Estudis d'assignació del projecte:
    GR ENG ALIMENT 2016

Lloc de realització:
EEABB

Paraules clau:
Crioconcentración asistida por vacío; concentración; lactosuero; lactosa; optimización.

Descripció del contingut i pla d'activitats:
Trabajo experimental para estudiar la criconcentración
asistida por vacío de tres sueros lácteos procedentes de la
fabricación de queso con leche de vaca.
El trabajo incluye una revisión bibliográfica inicial, la
caracterización de la materia prima (suero) procedente de la
elaboración de tres tipos diferentes de queso elaborado con
leche de vaca. En los ensayos previos se determinan los
límites de trabajo de las variables (presion y tiempo de
vacío) y se lleva a cabo la optimización mediante RSM. Una vez
definidas las condicions óptimas se extienden estas
condiciones a todos los tipos de suero.
Con los resultados se analiza la influencia de las variables
sobre los parámetros seleccionados y se estudian si hay
diferencias entre los diferentes tipos de suero.

Overview (resum en anglès): Cryoconcentration is considered an emerging technology in which a food fluid can be concentrated by freezing water. For this project, the vacuum-assisted block cryoconcentration of three types of cow’s milk was carried out, to assess optimal process conditions to maximize recovered soluble solids (SSR) and concentration index (IC).

An experimental design of 9 trials was planned with three replicates each, employing a combination of times of 20, 35 and 50 min and pressures of 10, 40 and 50 kPa vacuum.
After finishing the experimental phase, a Factor Analysis was performed using the statistical tool for Design of Experiments (DOE) provided by Minitab 19, to make an evaluation of the influences of the factors on the response variables IC and SSR, using two levels for the two factors: vacuum time at 20 and 50 min and pressure at 10 and 50 Kpa. Subsequently, the optimization of the system was carried out, adding central points and axial points to the Factorial Analysis, combined with the intermediate levels: vacuum time of 35 min and pressure of 40 kPa, creating a Central Composite Design, using the Response Surface methodology (RSM). In total, the Central Composite Design consisted of 4 trials of the Factorial Design, 1 central point and 4 axial points.

By means of Factor Analysis, the individual factors of time and vacuum pressure had a significant effect on IC and SSR and the interaction of pressure and time was significant for SSR, although it was a weak interaction. The quadratic terms were not significant except for the quadratic interaction (time•time) that was for SSR.

Through the Response Surface Analysis it was defined that to maximize CI, the ideal conditions were a time of 20 min and a vacuum pressure of 70 kPa, reached 6 times the initial concentration. To maximize SSR the optimal working conditions were a time of 50 min and a pressure of 10 kPa, achieving percentages higher than 60% of solids recovered.

Optimum conditions were applied during the cryoconcentration of different whey in order to determine the influence of this technique on the lactose content, concluding that lactose tends to spread more towards the concentrated fraction.

Keywords: Vacuum-assisted cryopreservation, concentration, whey, lactose, optimization.


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