Journal of Engineering & Processing Management (EPM)
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Osmotic dehydration of pineapple slices pre-treated by electroplasmolysis: Determination of color change kinetics
Full text linkThe pineapple (Ananas comosus (L.) Merrill) is a commercial tropical fruit belonging to the Bromeliaceae family. It is rich in organic acids (citric acid, malic acid), minerals (Fe, Mg, Ca, P, K, and Zn), and vitamins (A, B1, B2, B3, and B6). Osmotic dehydration is a water removal technique by immersing the fruit in a hypertonic solution to obtain minimally processed food with a longer shelf life and high nutritional value. It can also be considered as a pretreatment that reduces the required energy inputs for convective drying and freeze-drying. Electroplasmolysis is an electrical method that is based on the growth of pores in cell membranes. It has an important effect on the dehydration and extraction processes as it increases the cell permeability and mass transfer coefficients of plant tissues. In this study, it was aimed to determine the effect of electroplasmolysis pretreatment on color change kinetics in the osmotic dehydration of pineapple slices. Electroplasmolysis was applied by a drum‐type electroplasmolyzator with 80 V/cm voltage gradient for 60 s. The osmotic dehydration process was carried out with sucrose solutions of 40, 50 and 60 ◦Bx at 20 ◦C. The processing time was 6 h in all osmotic treatments. This time was determined in preliminary experiments. Osmotically dehydrated samples with elelctroplasmolysis pretreatment and the samples without electroplasmolysis application were compared via L, a, and b values during 8 hours. The results of the study showed that fresh pineapple samples had higher L, a, and b values than both electroplasmolysis treated and untreated samples. The color values of all the samples, with and without electroplasmolysis pretreatment, decreased parallel to time increase after the osmotic dehydration process. L, a, and b values of the samples which osmotically dehydrated at 60 ◦Bx solution were higher than the color values of the samples which were dehydrated at 40 and 50 ◦Bx solutions. Lightness and yellowness were found higher in the electroplasmolysis group than the other groups. The zero-order and first-order kinetic models were used to explain the color change kinetics and it was observed that L, a, and b were fitted to a first-order kinetic model
Building a MATLAB applicaton for preliminary design and optimization of shell and tube heat exchangers
Full text linkDesigning shell and tube heat exchangers is a complex and time-consuming procedure. Since they are one of the most common process units in process industry, great effort should be made to improve their design and to facilitate the design procedure. Therefore, in this study, an easy-to-use MATLAB application for shell and tube heat exchanger preliminary design and optimization was developed. The application enables users to select operating parameters manually and test their effect on heat transfer area and pressure drop. Moreover, the application helps users to optimize the preliminary design, in terms of finding the minimal heat transfer area required to meet the process requirements. The validity of the application was tested on the example from the literature, where the heat transfer area was 61.91 m2. During the proposed optimization procedure, different parameter values were tested and an optimal combination of parameters was found within 5 seconds (for all combinations), resulting in the heat transfer area of 53.27 m2. The application has a great feature of displaying the impact of baffle cut value and baffle spacing on most important design parameters: heat transfer area, tube-side pressure drops and shell-side pressure drops. Also, new correlations were developed for the calculation of the Colburn heat transfer factor and friction factor as a function of Reynolds number and baffle cut value. Overall, the application has proven to be useful for the preliminary design of shell and tube heat exchangers, and can represent the foundation for the development of advanced heat exchanger design applications
Nutritive and sensory quality of commercial dry - fermented sausages - ”ČAJNA” type with different salt content
Full text linkThe aim of this study was to evaluate the quality of dry-fermented pork sausages – “čajna” type from the market, with similar composition and different salt content. Physicochemical parameters of selected samples were determined and sensory quality parameters were evaluated. In samples M and D, with significantly higher (P ≤ 0.05) sodium chloride content, higher values of color parameter a* and breaking force and lower values of pH and water activity were found compared to samples T and L. Sample D had the highest protein (25.51%) and sodium chloride content (5.04%), and the lowest fat content (30.04%). Samples M and D had significantly higher sensory quality, especially odor, aroma, taste, consistency and cross-section, compared to other samples. These samples were evaluated as sausages with a pronounced pleasant aroma, taste and odor characteristic for dry-fermented products, with pleasant salinity, appropriate for the product. Although the dry-fermented sausage samples with a lower salt content had more acceptable nutritive values, their sensory quality was lower than expected
Effect of welded joint imperfection on the load-carrying capacity of pipe elbows subjected to in – plane bending moment
Full text linkThe defects in pipe elbows can, depending on their size and position, affect the integrity and safe service, as well as deformation ability of the piping systems in exploitation. Incompletely filled groove, which is the type of defect examined here, was observed by ultrasonic measurement on the pipeline in the regulation system of the hydro power plant Djerdap. Three-dimensional finite element analysis is performed using Simulia Abaqus software package. First, the models with dimensions of the defects observed by non-destructive examination are formed. Stress and strain fields for different loading types are shown and commented. The influence of the defect dimensions on the pipe elbow load-carrying capacity is determined through plastic collapse loads, which are obtained from bending moment - rotation angle diagrams. Twice elastic slope (TES) technique is applied. Additionally, some more severe defects are considered, in the form of sharp pre-cracks at the bottom of the defect; plastic collapse loads are also determined for these geometries. Both opening and closing bending moments are taken into consideration and the results are discussed and compared to two closed-form solutions from the literature. The influence of the boundary conditions applied for examination of the pipe elbows iscommented
Sweet bakery products for diabetic’s diet and analysis of risk associated with selected ingredients
Full text linkDiabetes is a complex, chronic illness that demands a healthy diet. The overall quality of consumed food is important for diabetics, but benefits are expected from whole grains and lower-energy food. Choice of appropriate sweet bakery product may present the problem for diabetics in meal planning. The aim of this research is to provide an overview of some opportunities for new food product development for persons with diabetes and to analyze the risks associated with selected food ingredients, which can be used. It includes identification of special requirements for controlled nutrition. Quality parameters and food product composition are determined on a formulation for muffins modified to contain ingredients recommended and safe for diabetics’ diet with lower energy value, but keeping prescribed and acceptable product quality. The research focuses on assessment of the risks analysis associated with selected ingredients on an example of muffin-like cake formulation modelling and use of wheat flour, sugars, fats, salt and some additional ingredients, milk, eggs and cocoa powder, based on experience, insight into recommendations for diabetics’ nutrition and scientifically identified indicators aimed at health protection. Methodology for the selection of the ingredients for energy-reduced muffin-like cakes with whole-grain wheat flour and cocoa, suitable for diabetics’ diet presented in the paper, can be used as a model for developing other products aimed to improve nutrition of persons with healthy food preferences or diseases. In addition, it presents an opportunity for the food industry contribution to healthy lifestyle by developing products adapted to modern dietary recommendations and target consumers group
Theoretical support of modern issues related to laser techniques, applications of coherent radiation and modern technologies
Full text linkModern problems of the Earth’s population are increasing in the areas related to the basic concepts of survival of living beings, but also with opposite views, if parallels are made between energy and ecology. Many new technologies are searching for their way towards development and must be viewed from several points of view. Inthis paper, the issue is addressed through modern laser techniques in terms of obtaining energy for various purposes concerning selected roles in medicine, as well as the impact on flora, fauna and as a support to other technologies both classical and modern. Contemporary attributes of lasers and other quantum generators in termsof coherence, power and intensity densities have significantly increased, although some predictions from the time of the first quantum generator masers, like gammarasers (and X raser) are still relatively far from commercial concepts. Some of the possible contemporary implementations of quantum generators in measurements control and processing schemes, along with other possible applications of various laser types, have been estimated. The paper focuses on the characterization of today’s problems with Covid-19 virus, only from the engineering point of view. The lexical side of the issue is also included, as well as the social management needswith the application of modern technologies, including help from natural sciences
Pharmacological potential of Thymus serpyllum L. (wild thyme) extracts and essential oil: A review
Full text linkIn traditional medicine Thymus serpyllum L. (wild thyme) herb represents a part of a large number of herbal medicinal formulations such as syrups, tinctures, infusions, teas, and decoctions. In recent years, there is a growing interest in testing the biological properties of wild thyme, because the plant is a high quality raw material, rich in essential oil and pharmacologically active polyphenolic compounds, which can be included in various formulations in the pharmaceutical, cosmetic, food, and chemical industries. Wild thyme extracts and essential oil have shown significant nitric oxide, ABTS and DPPH radicals scavenging potential, ferrous ion chelating property, reducing activity and ability to inhibit peroxidation of deoxyribonucleic acid (DNA), proteins and lipids. Wild thyme extracts exerted antibacterial activity against Bacillus cereus, Enterococcus faecalis, Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella enterica, Yersinia enterocolitica, as well as Lactic acid bacteria. Wild thyme essential oil has shown antibacterial potential against E. coli, L. monocytogenes, P. aeruginosa, S. enteritidis, S. aureus, Streptococcus salivariu, S. mutans S. sanguinis, S. pyogenes, E. feacalis, B. cereus, B. subtilis, B. pumilis, Lactobacillus acidophilus, Proteus mirabilis, Klebsiella pneumoniae, Salmonella choleraesuis, and Salmonella poona. T. serpyllum extract possesses antifungal activity against Fusarium solani, F. moniliforme, Aspergillus flavus, Microsporum canis, Alternaria species, Candida albicans, and C. glabarata. The essential oil efficiently inhibited the growth of C. albicans, C. glabrata and Aspergillus fungi. Wild thyme extract significantly and concentration-dependent relaxed spontaneous contractions, acetylcholine-, potassium chloride-, barium chloride- and calcium chloride-induced contractions of isolated rat ileum. The extract significantly reduced the expression of the inducible enzyme cyclooxygenase-2 and inhibited acetylcholinesterase, myeloperoxidase and α-glucosidase activity. T. serpyllum extract has shown cytotoxic activity on human breast cancer cell lines, while essential oil has shown the antitumor potential in human cell lung cancer, colon, cervical, hepatocellular, prostate, and breast adeno-carcinoma
Determination of the microplastic particle release by tea bags during brewing
Full text linkThe presence of microscopic particles of plastic (MP) in food is currently an urgent problem in the modern food industry and one of the main issues of food safety. However, there are no clear methods for the determination of such particles, nor methods for cleaning food products from them. In the present work, for the first time, the method of Dynamic Laser Light Scattering (DLS) was used to determine the plastic nanoparticles from tea bags when they were boiled in boiling water. It has been established that some of the studied samples of sachets release a huge amount of such nanoparticles into water. Moreover, hundreds of millions of nanoparticlesare released per one microscopic particle
Effects of drilling parameters on TI-6Al-4V alloy using different coolants
Full text linkThe formulation or application of coolants plays a critical role in machining to bring out the best finished products. In this scientific article, the study focused on the effects of coolants and machining parameters of Ti-6Al-4V are investigated with consideration of their performances by using drilling operation. The design of experiments (DOE) was considered and the performance of machining was measured with respect to cutting temperatures and surface responses. The final results put forward that the excellent surface finish and minimal cutting temperatures are obtained by application of power metcut s plus when compared with pure water. The factors that impact the surface roughness of Ti-6Al-4V are coolant and feed rate. The coolant also helps in the machining process by reducing temperature at the cutting zone
Neural network modeling methods for predicting the air parameters in the city of Tuzla
Full text linkAccording to the report of the World Health Organization, the city of Tuzla is the second in the world, and the first in Europe in terms of the number of diseases caused by air pollution. Tuzla Canton since 2003 has continuous air monitoring. Concentrations of individual pollutants exceed hourly, daily and annual limit values. In this paper, based on the existing results of air monitoring and meteorological data, using statistical methods and neural network modeling methods, unique and reliable models for predicting the concentration of NO2 in the air for the City of Tuzla have been developed. The results obtained using these models can be used in strategic decision-making processes and activities related to air quality control and management. This paper, on the example of the City of Tuzla, showed that using existing air monitoring data, concentrations of pollutants can be predicted for a longer period of time, using artificial intelligence methods. Reliable models with a high correlation coefficient can be obtained. In the case of a short or long interruption of the measurement of pollutant concentrations for the City of Tuzla with the help of models, which are the result of this work, it is possible to predict the concentrations of pollutants and plan to take measures based on them