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The effects of the mycotoxin patulin on the thermodynamics and kinetics of the transition of bovine serum albumin (BSA) in aqueous solution were studied by Differential Scanning Calorimetry and Photoluminescence methods. Results show that in the presence of patulin, the free enthalpy change during the transition of BSA was decreased by an average of ∼ 46 kJ/mol, the free energy change was decreased by ∼ 4 kJ/mol, and the activation energy fell from ∼ 1546 to ∼ 840 kJ/mol. These results indicate that the bioactivity of patulin is based on the kinetic rather than on the thermodynamic properties of the transition. This is the first evidence of the direct interaction of patulin with the free thiol-containing BSA, a process which could contribute to the adverse cyto- and genotoxic effects induced by patulin.
stability ( Arias et al., 2000 ; Arima et al., 2001 ; Amiri and Rahimi, 2014 , 2015 ). This was also evidently verified by differential scanning calorimetry thermo-gram for imidacloprid that exhibits a sharp endothermic peak nearby 133 °C (melting
with beech wood at about 27 °C. The smoking was followed by ageing for 35 days (12 °C, 75% RH). During the experiment, the NaCl content, color, water activity, denaturation temperature and enthalpy (differential scanning calorimetry) were measured on
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
rheological properties becoming pseudoplastic during frozen storage. During their studies, they noticed an increase in the viscosity due to frozen storage. Differential Scanning Calorimetry (DSC) is a thermo-analytical method, which is used to examine
- zs Malvern (U.K.) at 25 °C ( F an et al., 2007 ). 1.5 Differential scanning calorimetry (DSC) This method estimates the antioxidant ability of encapsulated extracts. This test was done at 0, 45, and 90 days after encapsulating the extracts by means
Effect of 60Co irradiation on wheat and white pepper grains were investigated in this study using Rapid Visco Analyser (RVA), near infrared reflectance spectroscopy and differential scanning calorimetry. Functional properties of wheat and white pepper were affected by irradiation indicated by a decrease in viscosity values. It was caused by changes of starch structure confirmed by the NIR spectra changes between wavelength 1560–1620 nm, which is the vibration of intermolecular hydrogen bonded OH groups in polysaccharides. The radiation used did not cause significant changes in the thermal properties. RVA proved to be useful for screening radiation induced changes in dry commodities of considerable large starch content on the basis of their rheological behaviour.
The role of fats in food technology is mainly to develop the desired consistency. The simplest way to reach this goal is the blending of different fats. The aim of our work was to study the solidification and melting properties of blends of coconut oil and anhydrous milk fat. Pure fats and their 25–75%, 50–50%, and 75–25% blends were investigated. Melting profile and isotherm crystallization were measured by pNMR. Non-isotherm melting and solidification were detected by differential scanning calorimetry (DSC). Possible applications of the blends were established. Results show that AMF and coconut oil has limited miscibility, which is dependent on the temperature. Below 22 °C AMF is the softening component, above 22 °C the effect is inverse. Coconut oil accelerates solidification of AMF, however, basic crystal forms of AMF remained.
Analysis of the binding interaction of (−)-epigallocatechin-3-gallate (EGCG) and pepsin is important for understanding the inhibition of digestive enzymes by tea polyphenols. We studied the binding of EGCG to pepsin using fluorescence spectroscopy, Fourier transform infrared spectroscopy, isothermal titration calorimetry, and protein-ligand docking. We found that EGCG could inhibit pepsin activity. According to thermodynamic parameters, a negative ΔG indicated that the interaction between EGCG and pepsin was spontaneous, and the electrostatic force accompanied by hydrophobic binding forces may play major role in the binding. Data from multi-spectroscopy and docking studies suggest that EGCG could bind pepsin with a change in the native conformation of pepsin. Our results provide further understanding of the nature of the binding interactions between catechins and digestive enzymes.
A recombinant Bacillus subtilis strain containing a plasmid encoding a luxAB fusion, which gave bioluminescence upon addition of an exogenous long-chain aldehyde as substrate for the endogenous luciferase enzyme, was used as test organism. Its populations were treated with 300 MPa for 20 min, or 600 MPa for 20 min at around room temperature, and this treatment is foreseen as a quality-friendly, non-thermal pasteurisation of foods. Besides the estimation of viable cell counts, the extent of pressure-induced germination and post-process development were investigated by phase-contrast microscopy, turbidimetry and luminometry. Increased heat sensitivity of pressurized spore populations was observed both by viable cell counting during a linearly programmed elevation of temperature and a simultaneous differential scanning calorimetry. This was related to pressure-induced germination of spores, although a small fraction remained ungerminated. The luciferase pool built into the spores during their formation seemed to have withstood pressurization. Spore germination was accompanied by the emergence of bioluminescence which also indicated sensitively the characteristic changes of metabolic activity running parallel with the development of untreated cell populations and that of the survivors of the hydrostatic pressure treatments when the cells were incubated in a nutrient broth.
