Immobilized yeast cells and secondary metabolites

The use of immobilized cell technology (ICT) is viewed as a promising biotechnological tool to achieve high volumetric productivities of yeast fermentation in bioindustry of alcoholic beverages. During this process a huge number of organic compounds are being formed as yeast secondary metabolites, among which volatile compounds, such as higher alcohols, esters, and vicinal diketones, are the most important flavoring compounds. The objective of this chapter is to summarize the knowledge on the origin of the flavor-active and nonvolatile compounds synthesized by yeast and to describe how the composition of the medium, culture strain, process conditions (temperature, aeration, etc.), bioreactor design, and other critical parameters influence the metabolic activities of yeast cultures. Despite the technological and economic advantages provided by ICT, commercialization of this technology experienced only limited success, mainly due to unpredictable effect of immobilization on yeast physiology. This chapter is an attempt to rationalize and make some conclusions about the impact of cell immobilization on yeast metabolism collected from empirical experiences in production of alcoholic beverages. The knowledge addressing this issue may be of particular benefit to the nascent bioflavor industry

Shungite – a carbon-mineral rock material: Its sinterability and possible applications

© 2019 University of Novi Sad, Faculty of Technology. All rights reserved. The paper presents results of the influence of mechanical activation of shungite, a carbon-mineral rock material rich in silica and carbon, on its sintering behaviour, and obtaining of pure SiC ceramics. The mechanical activation of the starting powder was performed in a high-energy ball mill in time intervals from 30 to 480 min. The phase composition of the starting powders and sintered samples was analysed by the X-ray diffraction method. The first traces of SiC were detected after sintering at 1350 °C for 2 h in an Ar atmosphere, along with traces of unreacted SiO2. The scanning electron microscopy was performed in order to determine changes in the microstructure. Sintering was performed at various temperatures for 2 h, in an Ar atmosphere and a vacuum. Dielectric properties of the sintered samples were measured in the frequency range from 1 to 500 MHz. The obtained results indicate that the sintered powder is a good candidate for applications as an absorber of electromagnetic waves in microwave engineering

Computation offloading for ground robotic systems communicating over WiFi – an empirical exploration on performance and energy trade-offs

Context: Robotic systems are known to perform computation-intensive tasks with limited computational resources and battery life. Such systems might benefit from offloading heavy workloads to the Cloud; however, in some cases, this implies high network traffic that degrades performance and energy consumption. Goal: In this study, we aim at evaluating the impact of different computation offloading strategies on performance and energy consumption in the context of autonomous robots. Method: We conduct two controlled experiments involving a robotic mission based on the Turtlebot3 robot and ROS 1. The mission consists of three tasks that are recurrent in robotics and good candidates for computation offloading in research, namely, SLAM mapping, navigation stack, and object recognition. Each of the tasks is either executed on board or offloaded in a full-factorial experiment design. The obtained measures are then statistically analyzed. Results: The results show that offloading the object recognition task causes a more significant decrease in resource utilization and energy consumption than both SLAM mapping and navigation. However, object recognition affects the volume of network traffic significantly to the extent that it can easily cause network congestion. Conclusions: In the context of our experiments (i.e., those involving small-scale ground ROS-based mobile robots operating under WiFi networks), offloading object recognition is beneficial in terms of performance and energy consumption. Nevertheless, large network bandwidth needs to be available for object recognition offloading. While the image resolution and frame rate have a significant impact on not only the network traffic but also energy consumption and performance, these parameters need to be carefully set so that the results of this task can be always received in time, which is particularly crucial in real-time systems.</p

Melt Dispersion Technique for Encapsulation

Encapsulation involves the coating or entrapment of a pure material or a mixture into another material. The coated or entrapped material, usually a liquid, is known as the “core” or “active” material, while the coating material is known as the “wall” material.1 At the end of any applicable technique for encapsulation, the nal products called particles (micro-or nanoparticle depending on the size) can be dried or not.2 Considering the aforementioned facts, a number of technologies have been used in the preparation of encapsulates, such as spray-drying, uidized-bed coating, spray-cooling, extrusion technologies, emulsication, inclusion encapsulation, coacervation, nanoencapsulation, and liposome entrapment. There are a number of excellent recent reviews summarizing all encapsulation processes.2-8 Although the principle of dispersing of a molten matrix has been frequently employed for production of encapsulates, there are not many, if any, papers overviewing the processes and equipments utilizing this principle. The aim of this chapter is to describe technologies utilizing melt dispersion, melt spraying, melt emulsication, and melt homogenization. It also surveys applications of melt dispersion, describes its advantages and limitations, and emphasizes trends and innovations

Enzyme Encapsulation Technologies and their Applications in Food Processing

The application of immobilized enzyme is strictly related to economic benefits of immobilization. Regardless of numerous patents and published articles, application of immobilized enzymes in food industry is relatively limited to several processes. Immobilization of enzyme onto inorganic carriers is a well-established technique, especially in the field of industrial applications. Zeolites are another group of inorganic materials that have been applied in enzyme immobilization. Cysteine was also found to be suitable as a binding agent for enzyme immobilization on to the glass surface. The covalent immobilization of enzymes onto epoxy-activated carriers has drawn considerable interest. A new process for synthesis of carriers, such as electrochemical synthesis of polyaniline, was found to be a promising procedure for production of stable enzyme support. Natural and synthetic polymer hydrogels have been frequently used for encapsulation of cells, enzymes and food compounds

DOI:10.2298/ABS1001075T EFFECTS OF CISPLATIN ON LIPID PEROXIDATION AND THE GLUTATHIONE REDOX STATUS IN THE LIVER OF MALE RATS: THE PROTECTIVE ROLE OF SELENIUM

Abstract –The role of oxidative stress in cisplatin (CP) toxicity and its prevention by pretreatment with selenium (Se) was investigated. Male Wistar albino rats were injected with a single dose of cisplatin (7.5 mg CP/kg b.m., i.p.) and selenium (6 mg Se/kg b.m, as Na2SeO3, i.p.) alone or in combination. The results suggest that CP intoxication induces oxidative stress and alters the glutathione redox status: reduced glutathione (GSH), oxidized glutathione (GSSG) and the GSH/GSSG ratio (GSH RI), resulting in increased lipid peroxidation (LPO) in rat liver. The pretreatment with selenium prior to CP treatment showed a protective effect against the toxic influence of CP on peroxidation of the membrane lipids and an altering of the glutathione redox status in the liver of rats. From our results we conclude that selenium functions as a potent antioxidant and suggest that it can control CP-induced hepatotoxicity in rats

The effects of a meldonium pre-treatment on the course of the faecal-induced sepsis in rats

Sepsis is a life-threatening condition caused by the dysregulated and overwhelming response to infection, accompanied by an exaggerated pro-inflammatory state and lipid metabolism disturbance leading to sequential organ failure. Meldonium is an anti-ischemic and anti-inflammatory agent which negatively interferes with lipid metabolism by shifting energy production from fatty acid oxidation to glycolysis, as a less oxygen-demanding pathway. Thus, we investigated the effects of a four-week meldonium pre-treatment on faecal-induced sepsis in Sprague-Dawley male rats. Surprisingly, under septic conditions, meldonium increased animal mortality rate compared with the meldonium non-treated group. However, analysis of the tissue oxidative status did not provide support for the detrimental effects of meldonium, nor did the analysis of the tissue inflammatory status showing anti-inflammatory, anti-apoptotic, and anti-necrotic effects of meldonium. After performing tissue lipidomic analysis, we concluded that the potential cause of the meldonium harmful effect is to be found in the overall decreased lipid metabolism. The present study underlines the importance of uninterrupted energy production in sepsis, closely drawing attention to the possible harmful effects of lipid-mobilization impairment caused by certain therapeutics. This could lead to the much-needed revision of the existing guidelines in the clinical treatment of sepsis while paving the way for discovering new therapeutic approaches

Characterization of commercially available products of aronia according to their metal content

Introduction. Among different fruit species, aronia have attracted a great attention because of its wide range of protective effects with potential benefits for human health. Furthermore, the consumption of products of aronia (juice, tea, berries) is becoming a part of a healthy lifestyle. Materials and Methods. The multi-element characterization of products of aronia has been carried out using inductively coupled plasma atomic emission spectrometry (ICP-AES). Results and Discussion. Among the major elements, the most abundant are K, Ca and P, followed by the Mg and Na. Fe, Zn, Mn, Cu, Bi and Si are the most abundant among the microelements. In terms of heavy metals (As, Cd, Pb), it can be concluded that the concentrations of them are below permissible levels (PLs) prescribed by national legislation in all samples. The chemometric techniques of principal component analysis (PCA) and cluster analysis (CA) were used to differentiation of products aronia according to their metal content. The application of PCA and CA was resulted in two clusters with similarities in the mineral composition. The first cluster includes tea bag samples (T1-T6). The second cluster includes berries (B1, B2), juices (J1-J4) and leaves (L). Conclusion. Data obtained in this study showed that analyzed products are potentially a rich source of some dietary metals such are K, Ca, P, Mg, Na, Fe and Zn. Obtained results could be also used as selection criteria for further use of products of aronia as a part of conventional diet