Abstract: Dynamic viscosity of wort was observed during lager beer base processing. The wort samples were separated in 11 different stages of brewing base preparation. Viscosity was measured by means of rotary viscometer with concentric cylinders geometry. Viscosity gradually increased from 1.75 to 2.1 mPas. Experimental data were mathematically modelled, using Gaussian, exponential, linear, and power law fit. Curve fitting application (MATLAB) was used. The highest correlation (R2=0.9975) was achieved for Gaussian equation. Obtained dependencies and descriptions represent a powerful tool for predicting wort behavior and designing of brewery technological processes.
Abstract: A tojásfehérje mikrobiológiailag erősen szennyezett lehet, ugyanakkor fehérjéi
hőre érzékenyek. Ezért hőkezelési hőmérsékletének és idejének
megválasztásánál egy optimumkeresésre van szükség, melyben a minél nagyobb
arányú mikrobapusztulás mellett a fehérjék natív állapotának megtartása a cél.
Munkánk során differenciális pásztázó kalorimetria (differential scanning
calorimetry = DSC) módszerrel azt vizsgáltuk, hogy a különböző tojásfehérje
hőkezelési eljárások hogyan változtatják meg a minták kalorimetrikus
tulajdonságait.
Méréseink során a natív, a pasztőrözött és az 53 °C-on 24 órán át hőntartott
tojásfehérje-lé termékek denaturációs hőmérsékleteiben nem tapasztaltunk
szignifikáns eltérés. Ugyanakkor a rehidratált tojásfehérjepor fehérjéinek
szerkezete jelentősen eltérő volt (az ovoalbumint tartalmazó csúcs 3-4 °C
eltolódását tapasztaltuk).
Egg white might be highly microbiologically contaminated but its proteins are
sensitive to heat. Therefore in choosing the temperature and duration of heat
treatment an optimum searching is required with the purpose of maintaining
native condition of proteins with the highest possible rate of microbial
destruction.
In our work we tested the way the various egg white heat treatment methods
affect the calorimetric properties of the samples by using differential scanning
calorimetry (DSC).
Our tests have shown no significant differences in the denaturation temperature
of the native, the pasteurized and the maintained at 53°C for 24 hours liquid egg
white. However, the protein structure of the reconstituted egg powder was
markedly different (3-4°C shift in ovoalbumin-containing peak was observed).
Abstract: Quantification and evaluation of peach (Red Heaven) stone shape variability was performed. Peach stones' shapes were described by several methods: measuring of main axes dimensions with consequent calculation of variation coefficients and expression of shape index; surface description by means of 3D scanning; and shape variation evaluation based on elliptic Fourier descriptors. The last approach enabled definition of influence of height to width ratio, position of the center of gravity, curvature, and degree of roundness. The scores of the resulting components were used in subsequent analysis as stone shape characteristic. The variation in shape accounted for by each component was visualized using inverse Fourier transformation. The first four principal components provide a good summary of the data, accounting for almost 100 % of the total variance. Dominant importance and relevance of length to width ratio (with contribution of 44.24 % to the total variance) as a determining parameter of stone shape was quantitatively confirmed.