Authors:É. Andrássy, J. Farkas, Zs. Seregély, I. Dalmadi, E. Tuboly, and V. Lebovics
Experiments were performed to study changes caused by irradiation or high hydrostatic pressure pasteurization of liquid egg white by differential scanning calorimetry, spectrofluorimetry, electronic nose measurements and NIR-spectrometry. The non-thermal pasteurization treatments were also assessed in relation to loss of carotenoid content, and lipid- and cholesterol oxidation of liquid egg yolk. Unlike radiation pasteurization, high pressure processing caused protein denaturation in egg white, which manifested in changes of its DSC-thermogram and intrinsic tryptophan fluorescence. Electronic nose testing showed changes of the head-space volatile composition of egg albumen, particularly as a function of radiation treatment. Both treatments caused changes in the NIR-spectrometric “fingerprint” of the liquid egg white. Various chemometric analyses of the results of the latter instrumental methods, particularly statistical techniques developed by the group of one of the co-authors of this article, demonstrated the potential for detection and characterization of the applied non-thermal processing techniques on liquid egg white. Irradiation induced more carotenoid degradation and lipid oxidation in liquid egg yolk than pressure processing.
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:I. Cioffi, L. Santarpia, A. Vaccaro, M. Naccarato, R. Iacone, M. Marra, F. Contaldo, and F. Pasanisi
The interest in gluten-free (GF) diet has greatly increased also in people without celiac disease (CD). This pilot study aimed to investigate the postprandial effect of GF-pasta, made by using the pasta-making process applied to artisan wheat pasta, on palatability, appetite sensation, and glucose metabolism in 8 healthy volunteers. Two iso-caloric lunch-meals consisting of: 1) gluten-free pasta (GFP) and 2) refined wheat pasta (RP) were compared in cross-over design. Both subjective appetite, assessed by visual analogue scale (VAS), and blood sample were taken before meal and at half-hour intervals for 4 hours. Palatability was evaluated immediately after the meal-test by VAS. All participants underwent pre- and postprandial energy expenditure (EE) measured by indirect calorimetry. We found that subjective palatability did not significantly differ between meals. Similarly, repeated measures ANOVA showed that GFP did not affect appetite ratings, postprandial glucose, and insulin responses compared to RP. Then, postprandial EE was affected by time (P=0.006), increasing at 60 min, but not by meals. In conclusion, artisanal GFP was as palatable as RP pasta, without affecting perceived satiety and postprandial glycaemia compared to RP in healthy subjects. Clearly, GFP results are preliminary and need to be investigated in larger studies.
Authors:Emna Ayari, Csaba Németh, Karina Ilona Hidas, Adrienn Tóth, Dávid Láng, and László Friedrich
Starting from mechanical revolution, each day new methods and new equipment have emerged. Today, the Ultra Heat Treatment (UHT) is one of the important technologies that permits to the industry to reduce processing time while maintaining the same quality of the products. Egg and egg products are known as heat-sensitive products, so the UHT enables us to preserve their qualities after a heat treatment.
Our aim is to study the effect of UHT treatment (approximately 67 °C for 190 s) on the Liquid Egg Yolk (LEY). For twenty-one days, the color and the apparent viscosity were measured every seven days, we also studied the damage of protein using DSC (Differential Scanning Calorimetry).
Comparing the two graphs of DSC, the denaturation of protein is distinct. The endothermic peak decreased. This could be seen also on the rheological curves. The apparent viscosity is diminished from 231 mPa.s on the 1st day of storage to 224 mPa.s on 21st day. However, the treated LEY could be stored for longer period than the raw LEY.
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