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Thermal characteristics of dried sugar beet pulp, leaves and leaf fractions obtained after extraction: fibrous leaf pulp and fibre rich leaf fraction, were investigated by differential scanning calorimetry and thermogravimetry. The sugar beet samples showed a similar thermal behaviour associated with a similar composition. Two endotherms are found on the differential scanning calorimetry curves. First one in the temperature range 31–153 °C and the second from 150–160 °C. Thermal degradation kinetics was studied by thermogravimetric analysis. Four degradation stages were observed within the temperature range 25–700 °C. The kinetic parameters of the degradation, obtained by Ortega and Friedman non-isothermal isoconversional methods did not significantly differ between models: Ea-activation energy at a conversion degree 0.1–0.9 ranged 50–200 kJ/mol; lnA- the natural logarithm of the pre-exponential factor 8–48; kp1-thermal degradation rate constant at a conversion extent of 0.5 ranged of 0.19–2.55 min−1. Constant rate of degradation is highest for the sugar beet leaves kp1 (2.58–2.55 min−1), and kp2 (70.1–70.4 min−1). The results obtained are valuable for sugar beet leaf industrial processing. A positive environmental impact is achieved by transforming the waste into high-value food additives. [ABSTRACT FROM AUTHOR]

Studies were conducted to evaluate and compare the kinetic parameters related to the oxidation process of blackberry and raspberry seed oils in non-isothermal conditions by DSC. For that purpose, the oil samples were heated at six different heating rates, β (2, 5, 7.5, 10, 15, 20°C/min), starting from 40°C to the beginning of the oxidation process, under an oxygen flow of 50 ml/min. Experiments were performed using TA Instruments DSC Q1000, Differential Scanning Calorimeter (Delaware, USA). Kinetic parameters (activation energy, Ea (J/mol) andpre-exponential factor, A (min-1)) were calculated using isoconversional Ozawa-Flynn- Wall (OFW) method. Using the values of Ea and A the oxidation rate constant was calculated at 25°C and 120°C by Arrhenius equation. The oxidation rate constants of raspberry seed oil was about 2 times higher than that of blackberry seed oil, which indicates that blackberry seed oil is more stable in terms of oxidation.

The kinetic properties and thermal characteristics of fresh pork meat proteins (Longissimus dorsi), as well as osmotically dehydrated meat proteins, were investigated using differential scanning calorimetry. Two isoconversional kinetical methods, namely the differential Friedman and integral Ortega methods, were employed to analyze the data. The obtained kinetic triplet, activation energy, pre-exponential factor, and extent of conversion, has been discussed. The resulting activation energy for proteins of fresh meat ranges between 751 kJ·mol−1 for myosin, 152 kJ·mol−1 for collagen and sarcoplasmic proteins, and 331 kJ·mol−1 for actin at a conversion degree of 0.1 to 0.9. For osmotically dried pork meat proteins, the values range from 307 kJ·mol−1 for myosin 272 kJ·mol−1 for collagen and sarcoplasmic proteins, and 334.83 kJ·mol−1 for actin at a conversion degree from 0.1 to 0.9. The proteins of the dry meat obtained by osmotic dehydration in molasses could be described as partly unfolded as they retain the characteristic protein denaturation transition. Concerning the decrease in enthalpies of proteins denaturation, thermodynamic destabilization of dried meat proteins occurred. On the contrary, dried meat proteins were thermally stabilized with respect to increase in the temperatures of denaturation. Knowledge of the nature of meat protein denaturation of each kind of meat product is one of the necessary tools for developing the technology of meat product processing and to achieve desired quality and nutritional value. The kinetic analysis of meat protein denaturation is appropriate because protein denaturation gives rise to changes in meat texture during processing and directly affects the quality of product. [ABSTRACT FROM AUTHOR]

Studies were conducted on thermal properties of oils extracted from raspberry and blackberry seed as well as flours obtained by grinding of seed. Crystallization and melting points of oils were measured with a Differential Scanning Calorimetry (DSC), using TA Instruments DSC Q1000, under N2 purge flow of 50 ml/min. DSC scans were conducted in temperature range of 40 °C to -90 °C. A programmed cycle was followed in which the sample was cooled from 40 °C to -90 °C and heated back to 40 °C with rate of 2 °C/min. The raspberry and blackberry seeds oils presented a crystallization peak at -66 °C and -61 °C with enthalpy of 25.10 J/g and 29.04 J/g, respectively. Polymorphism was detected in both oils during heating.

This survey was conducted on thermal properties of flours obtained by grinding of blackberry ( Rubus fruticosus L., Čačak Thornless cultivar) and raspberry ( Rubus idaeus L., Willamette cultivar) seeds, as well as oils extracted from berry seeds. Thermal behavior and stability of berry seed flours were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TG). Crystallization and melting points of oils were determined using a conventional and modulated DSC techniques. Oils present in the blackberry and raspberry seeds start melting ( T on ) at −24.02 and −26.44 °C, respectively. Both berry seeds thermo-oxidatively decompose at temperatures above 210 °C. Thermo-oxidative decomposition of these seed flours takes place in two stages, as TG/DTG curves have two thermal decomposition steps. Polymorphism was detected in both seed oils during heating. [ABSTRACT FROM AUTHOR]

Differential scanning calorimetry (DSC) technique is used to study the oxidative stability of blackberry ( R. fruticosus L., Čačak Thornless cultivar) and raspberry ( Rubus idaeus L., Willamette cultivar) seed oils. Oxidative stability of the oil samples was studied in an oxygen atmosphere, isothermally at eight temperatures, T i (110, 115, 120, 125, 130, 135, 140 and 145 °C) and non-isothermally at six heating rates, β i (2, 5, 7.5, 10, 15, 20 °C/min). Fatty acid composition was analyzed by gas chromatography (GC–MS). High content of essential fatty acids (linoleic and linolenic acid) was detected in both oils. Reaction rate constants ( k ) and activation energies ( E a ) of oil oxidation process were calculated for both isothermal and non-isothermal conditions. Blackberry seed oil was shown to have greater oxidative stability than raspberry seed oil because of a smaller quantity of linolenic fatty acid. [ABSTRACT FROM AUTHOR]

Rosemary (Rosmarinus officinalis L.) is a plant worldwide cultivated mainly for essential oils, extracts, and as a spice. Up-to-date results showed diversity in composition of the essential oils, which may influence their quality, biological activity, and thermal properties. Therefore, the aim of this study was to investigate the chemical composition, antimicrobial activity, and thermal properties of the rosemary essential oils originating from Serbia and Russia. Additionally, oils were added to the sunflower oils in order to investigate possible antioxidant activity during the frying. Investigation of the chemical profile marked α-pinene, eucalyptol, and camphor as the most abundant compounds in both oils. However, overall composition influenced in such manner that Russian oil showed significantly higher antimicrobial activity, while Serbian oil proved to be better antioxidant agent in case of frying of sunflower oil. This would significantly influence possible application of the oils, which could be used as an antioxidant agent for extension of the food shelf life, or antimicrobial agent for protection against different microbial strains. [ABSTRACT FROM AUTHOR]