Application of mathematical models in milk coagulation process during lactic acid fermentation. Part I. Relation betwen enzymmatic and acidic milk coagulation

Acidic and enzymatic coagulation of milk are complex processes which proceed in several phases and are dependent upon many different parameters. The formation of coagulum during lactic-acid fermentation is in fact acidic coagulation of milk. It occurs because of an increase in concentration of lactic acid, which causes a decrease in pH. Enzymatic coagulation of milk has been analytically described by means of mathematical models by many authors. Although enzymatic and acidic coagulation of milk do not proceed according to identical physical and chemical rules, it is possible to compare them kinetically. The aim of this paper was to combine the kinetics of enzymatic and acidic coagulation of milk and to mathematically present the changes that develop during lactic-acid fermentation of milk. The models presented in this paper enable a more complex mathematical analysis of the coagulation of the protein content of milk during lactic-acid fermentation. Application of the models enables the analysis and comparison of the kinetics of coagulation in different types of milk and various types of fermented dairy products manufactured with lactic acid bacteria. Mathematical combination of coagulation kinetics of the protein complex in milk with reological characteristics of the obtained fermented dairy products enables easier defining of parameters for lactic acid fermentation

Low thermal conductivity of the superfast rotator (499998) 2011 PT

Context: Asteroids with a diameter of up to a few dozen meters may spin very fast and complete an entire rotation within a few minutes. These small and fast-rotating bodies are thought to be monolithic objects because the gravitational force due to their small size is not strong enough to counteract the strong centripetal force caused by the fast rotation. Additionally, it is not clear whether the fast spin prevents dust and small particles (regolith) from being kept on their surface. Aims: We develop a model for constraining the thermal conductivity of the surface of the small, fast-rotating near-Earth asteroids. This model may suggest whether regolith is likely present on these objects. Methods: Our approach is based on the comparison of the measured Yarkovsky drift and a predicted value using a theoretical model that depends on the orbital, physical and thermal parameters of the object. The necessary parameters are either deduced from statistical distribution derived for near-Earth asteroids population or determined from observations with associated uncertainty. With this information, we performed Monte Carlo simulations and produced a probability density distribution for the thermal conductivity. Results: Applying our model to the superfast rotator asteroid (499998) 2011 PT, we find that the measured Yarkovsky drift can only be achieved when the thermal conductivity $K$ of the surface is low. The resulting probability density function for the conductivity is bimodal, with two most likely values being around 0.0001 and 0.005 W m$^{-1}$ K$^{-1}$. Based on this, we find that the probability that $K$ is lower than 0.1 W m$^{-1}$ K$^{-1}$ is at least 95\%. This low thermal conductivity might indicate that the surface of 2011 PT is covered with a thermal insulating layer, composed of a regolith-like material similar to lunar dust.Comment: Accepted for publication in A&A. 13 pages, 7 figures, 2 table

The feasibility of pulsed light processing in the meat industry

Today, the increasing demand for minimally processed foods that are nutritious, sensorially acceptable, and free from microbial, chemical and physical hazards, challenges research and development to establish alternative methods to reduce the level of bacterial contamination. As one of the newly developing non-thermal methods, pulsed light is a technology for the fast, mild, and residue-free surface decontamination of meat and meat contact materials in the meat processing environment. This review provides specific information on pulsed light technology and the feasibility of its application for unpackaged and packaged meat and meat products as well as meat contact materials. The advantages, limitations and achieved effects of pulsed light on microbial inactivation, lipid peroxidation, sensory quality and color of meat, seafood and meat products are illustrated and discussed in relation to its implementation on the industrial level

Impact of the geographic factors on the transport of lead and cadmium in the air

The aim of this study is to describe the effect of geographical varieties on the transport of lead and cadmium in the air. During period between 1997- 2006, the concentrations of lead in suspended in the air at 5 measuring sites in Serbia were measured. The minimal measured daily concentrations of lead ranged from 0,42 μg/m3 (2002.) in Kraljevo. The maximal measured daily concentrations of lead to 251,8 μg/m3 (2004.) in Belgrade. During the period between 1997-2006., the concentrations of cadmium in suspended in the air at 5 measuring sites in Serbia were measured. The minimal measured daily concentrations of cadmium ranged from 0,1 μg/m3 (1999) in Kraljevo. The maximal measured daily concentrations of lead to 42,0 μg/m3 (2000) in Belgrade. Results from our experiments demonstrated that when rapid infiltration conditions or a rainstorm exist, particle-facilitated transport of contaminants is likely to the dominant metal transport pathway influenced by acid rain.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

An insight into in vitro antioxidant activity of Cantharellus cibarius hot water extract for the potential application in meat products

The current research was undertaken to estimate the in vitro antioxidant activity of Cantharellus cibarius mushroom extracted by boiling in water for 30 minutes. Several previous studies have shown that the addition of edible mushrooms in meat products affects the reduction of lipid oxidation and prolongs the shelf-life of the final products. Antioxidant capacity of C. cibarius was measured using the following methods: reducing power ability, lipid peroxidation assay, cupric ion reducing antioxidant capacity (CUPRAC) and DPPH free radical scavenging activity. Reducing power and antioxidant activity assays of C. cibarius hot water extract showed low antioxidant activity. CUPRAC assay demonstrated positive effect only at the concentration of 10 mg/mL, whereas DPPH radical scavenging activity showed moderate antioxidant activity in comparison with culinary-medicinal mushrooms, with the effective concentration (EC50) from 7.41 mg/mL

Integument in Apfelbeckia insculpta (L. Koch, 1867) (Diplopoda, Callipodida) – morphoanatomical and ultrastructural study

The morphoanatomical and ultrastructural features of the integument (cuticle + epidermis) of an endemic Balkan millipede, Apfelbeckia insculpta (L. Koch, 1867), are investigated utilizing light (LM) and transmission electron microscopy (TEM). Cuticle consists of epicuticle (outermost layer), exocuticle, endocuticle and membranous layer that is in contact with the underlying epidermis. Epicuticle is layer of varying thickness, while exocuticle is composed of helicoidally arranged sheets of microfibriles that appear as close-spaced light and dark bands. Endocuticle is the widest part of cuticle with the broad light bands that are oriented in the same direction. TEM micrographs show that these bands are composed of lamellae arranged in arcuate pattern and curved microfibriles. Membranous layer is intersected in some regions by canals that connect epidermis and different levels of the cuticle and/or surface. The epidermis is monostratified layer of cells that are characterized by distinct polarity. Basal part of epidermal cells is rich in rough endoplasmic reticulum and mitochondria, while apical part contains numerous osmiophilic granules. Nuclei of epidermal cells are ovoid and positioned in different regions of cells. Interdigitations are formed among cells in some epidermal regions. Our study corroborates previous findings on integument organization in Diplopoda and shows that species-specific patterns of cuticular ultrastructure can be present in these arthropods

Is WO3 catalyst for hydrogen desorption?

Magnesium hydride, as hydrogen storage material, meets the requirements such as high gravimetric hydrogen capacity (7,6 wt%), low cost and weight, abundance and H2 absorption/desorption cycling possibility. Given that the oxide additives show the good impact on desorption properties, mechanical milling of MgH2 with addition of 5, 10 and 15% wt. WO3 was performed. The microstructure and morphology of composites were analysed by XRD, PSD and SEM and correlated to hydrogen desorption properties which have been investigated by DSC. The results have shown that WO3 has a positive effect on the desorption kinetics as well as on the change of the desorption mechanism

Chirikov Diffusion in the Asteroidal Three-Body Resonance (5,-2,-2)

The theory of diffusion in many-dimensional Hamiltonian system is applied to asteroidal dynamics. The general formulations developed by Chirikov is applied to the Nesvorn\'{y}-Morbidelli analytic model of three-body (three-orbit) mean-motion resonances (Jupiter-Saturn-asteroid system). In particular, we investigate the diffusion \emph{along} and \emph{across} the separatrices of the (5,-2,-2) resonance of the (490) Veritas asteroidal family and their relationship to diffusion in semi-major axis and eccentricity. The estimations of diffusion were obtained using the Melnikov integral, a Hadjidemetriou-type sympletic map and numerical integrations for times up to $10^{8}$ years.Comment: 27 pages, 6 figure

Supplementary data for the article: Dinić, J.; Novaković, M.; Podolski-Renić, A.; Stojković, S.; Mandić, B.; Tešević, V.; Vajs, V.; Isaković, A.; Pešić, M. Antioxidative Activity of Diarylheptanoids from the Bark of Black Alder (Alnus Glutinosa) and Their Interaction with Anticancer Drugs. Planta Medica 2014, 80 (13), 1088–1096. https://doi.org/10.1055/s-0034-1382993

Supplementary material for: [https://doi.org/10.1055/s-0034-1382993]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/1845

Supplementary data for article : Kolarević, S.; Milovanović, D.; Kračun-Kolarević, M.; Kostić, J.; Sunjog, K.; Martinović, R.; Đorđević, J.; Novaković, I.; Sladić, D.; Vuković-Gačić, B. Evaluation of Genotoxic Potential of Avarol, Avarone, and Its Methoxy and Methylamino Derivatives in Prokaryotic and Eukaryotic Test Models. Drug and Chemical Toxicology 2019, 42 (2), 130–139. https://doi.org/10.1080/01480545.2017.1413108

Supplementary material for: [https://doi.org/10.1080/01480545.2017.1413108]Related to published version: [http://cherry.chem.bg.ac.rs/handle/123456789/322