Authors:Á. Vajda, I. Zeke, R. Juhász, J. Barta, and Cs. Balla
The aim of the present study was to examine the infuence of hydrolyzed, nanofltered concentrate of the ultrafltered permeate (HNF concentrate) of acid whey on the quality characteristics of milk-based ice cream. Thermophysical properties were determined by differential scanning calorimeter, consistency was measured by oscillatory rheometer, and sensorial quality was evaluated by scoring method. It was concluded that the acid whey did not increase the melting of the product, and reduced the freezing point. Cryoscopic temperature, onset point, and glass transition temperature (Tg) gradually decreased as the quantity and proportion of acid whey increased in the ice-cream. Rheological results indicated that using HNF, acid whey produced more creamy and smooth ice-cream. However, because of its characteristic taste, maximum 20% of milk could be replaced by HNF acid whey in milk-based ice-creams.
Authors:A. Soós, Cs. Pecznyik, L. Somogyi, and I. Zeke
Palm fat is one of the most commonly used fats in food industry. The main role of palm fat is to develop the desired texture of food products. Fat blends were developed to find the most appropriate mixture fitting the technological needs. In our work palm mid fraction (PMF) was mixed with anhydrous milk fat (AMF), goose fat (G), and lard (L) in a 1:1 ratio. Anhydrous milk fat represents fat consisting of a wide range of fatty acids. Goose fat is a soft, easily melting fat, and lard is characterized as animal fat with wide melting temperature interval. The measurements aimed to establish the miscibility of the fats and the effect of animal fats on the melting-solidification profile of palm mid fraction. SFC vs temperature curves, Differential Scanning Calorimetry (DSC) melting thermograms describe the melting profile of the samples. Isotherm crystallization by SFC vs time curves and DSC cooling thermograms were measured to characterize the solidification of pure fats and the blends. Since the SFC curves did not show crosspoints we concluded that fats blended in a 1:1 ratio were miscible. Anhydrous milk fat strongly modified the properties of palm mid fraction, the blend became similar to anhydrous milk fat. Goose fat had no strong modification effect on palm mid fraction and could be considered as a softening agent. The effect of lard was complex: melting and solidification behaviour of the blend differed from the characteristics of both parent fats.
Authors:D. Nagy, M. Krassóy, I. Zeke, K. Pásztor-Huszár, and Cs. Balla
The aim of the study was to select the most suitable freezing and thawing method for preserving the quality of pasta flata type Parenica cheese comparing different methods: slow, shock (circulated air) and cryogenic freezing and thawing at room temperature and in a refrigerator, respectively. To observe the effects of these methods on some cheese properties weight, pH, and dry-matter content were measured, stringiness was examined, and compression test were performed for texture analysis. Thermophysical properties were determined by DSC: unfreezable water content, onset point of melting, and latent heat. Sensory analyses were also carried out by profle analysis. Results of objective and subjective measurements showed similar trends: characteristics of cheese samples frozen in circulated air and thawed in refrigerator resembled the most to the control sample.
Authors:B. Csehi, E. Szerdahelyi, K. Pásztor-Huszár, B. Salamon, A. Tóth, I. Zeke, G. Jónás, and L. Friedrich
In the experiments pork loin and beef sirloin were treated by pressures of 100 to 600 MPa by 100 MPa steps for 5 min. Colour changes of samples and the changes of proteins were investigated. The latter were examined with isoelectric focusing and SDS polyacrylamide gel electrophoresis. We found that myoglobin behaved completely differently in case of the two different species. Myoglobin has mostly lost its native state at 300 MPa pressure in case of pork, but the beef myoglobin could remain native even up to 500 MPa. The treatment at 300 MPa or higher pressure values caused almost complete aggregation and denaturation in case of pork and beef proteins. The results of SDS-PAGE and the colour measurement confirmed this finding.