Search Results
period up to 21 days was necessary for the sponge cakes investigated by differential scanning calorimetry (DSC), because no retrogradation transition was registered up to the sixth day. The humidity and the temperature were kept constant in desiccator
from the reading ( α ), constant of the measuring system ( z = 195.5 ) and the velocity gradient ( D = 57.20 s −1 ). Shear stress: τ = α ∗ z [ mPa ] Dynamic viscosity: η = τ D [ mPa ] 2.5 Thermodynamic measurement (DSC) A Micro DSC III
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.
This study aimed to evaluate the survivability of lactobacilli cells encapsulated in calcium alginate beads coated with methacrylic acid copolymers (MAc) in high acidic foods (orange juice and mayonnaise). Lactobacilli survived well at low temperature (4 °C) for 6 wk in orange juice, 4 wk in heat-treated orange juice, 12 wk in mayonnaise, and 8 wk in heat-treated mayonnaise (P<0.05), without affecting the acidity of orange juice and mayonnaise during storage. FTIR spectra showed that the characteristic peaks of calcium alginate and MAc were not altered, designating no high affinity interaction between calcium alginate and MAc. DSC of MAc-coated alginate beads indicated an increased in melting temperature, demonstrating improvement in molecular orientation in the MAc-coated alginate beads compared to the control. Sensory evaluation revealed that panellists could detect the presence of MAc-coated alginate beads, leading to a lower acceptance score.
evaluated and completed by DSC and TG analyses. 1 Materials and methods 1.1 Materials Grated red cabbage purchased from a local farmer (Sibiu, Romania) was subjected to ovendrying at 40 °C for 12 h (Memmert 100-800) and freeze-drying at –50 °C for 24 h
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.
2224 2229 Aktas, N., Tülek, Y. & Gőkalp, H.Y. (1997): Determination of freezable water content of semimembranous muscle DSC study. J. Thermal Anal., 48, 259
Influence of gamma irradiation ( 60 Co-rays) with doses in the range up to 30 kGy was studied on gelatinisation of wheat starch, wheat flour and potato starch. Differential scanning calorimetry was then applied at several heating and cooling cycles for studies of the effect of irradiation with a 30 kGy dose on interaction of wheat starch with their native lipids and potato starch with admixed 1-mono-lauroyl glycerol.Amylose-lipid complex transition occurs after irradiation at decreased temperature and is accompanied by decreased enthalpy in respect to that recorded in the case of non-irradiated wheat starch, wheat flour as well as potato starch and admixed lipid. Differences between the initial and irradiated starch were easier to detect on the foregoing heating or cooling cycles than during the preceding ones and after the gels’ retrogradation. The complex was less influenced by the less advanced retrogradation taking place in the irradiated than in the non-irradiated wheat flour. Radiation-induced modification of structural properties of the complex results due to degradation of starch granules confirmed at present by essential reduction in pasting properties and by the increased amount of short molecular products leached during gelatinisation and their higher branching.
Elderberry pomace, by-product of juice pressing procedure, is still rich in biologically active compounds, especially antioxidants and phenolic compounds. The aim of the present study was to investigate whether elderberry pomace could be utilized as a source of natural colourings and preservatives. By a simple solvent extraction a proper food colouring could be produced from elderberry pomace characterized by similar colour values as pressed elderberry juice. A solvent ratio of 1:20 with 50% ethanol proved to be the optimal solvent extraction method to produce an extract rich in antioxidants showing inhibitory effect against Lysteria monocytogenes and Enterococcus faecalis. In elderberry pomace extract three main phenolic compounds: chlorogenic acid, rutin and coumaric acid have been identifed by HPLC analysis. Based on our results, elderberry pomace, a by-product of fruit processing technologies, seems to be suitable for developing natural food additives after appropriate clarifcation processes.
2010 62 1 16 Giancola, C., De Sena, C., Fessas, D., Graziano, G., Barone, G. (1997) DSC studies on bovine serum albumin
