Atomska apsorpcijska spektrofotometrija i njena primjena u određivanju mineralnog sastava mlijeka

Instrumentalne metode kvalitativnih i kvantitativnih analiza kemijskih supstanci danas su vrlo brojne i raznovrsne, te zauzimaju značajno mjesto u analitičkim istraživanjima. Instrumentalnim analizama mjeri se neka od fizičkih osobina supstance i na osnovu toga određuje njen kemijski sastav. U posljednje vrijeme one se sve više primjenjuju jer skoro svaka fizička osobina nekog spoja može biti polazna osnova za razvoj neke instrumentalne tehnike

Determination of air consumption in biological process of sanitary wastewater treatment in sequencing batch reactors (SBR) on the example of a plant with a capacity of 1000 ES

Prečišćavanje otpadnih voda primenom biološke obrade za slučajeve manjih kapaciteta najčešće se odvija u sekvencijalnim šaržnim reaktorima (SBR – Sequencing Batch Reactor). U radu se razmatra način definisanja potrošnje vazduha u SBR postrojenjima za tretman sanitarnih otpadnih voda u fazi biološke obrade. Specifičnost rada SBR postrojenja je odvijanje procesa u ciklusima koji se sastoje od više faza pri čemu se u pojedinim fazama vrši aeracija uvođenjem vazduha pomoću distributera – aeratora. Karakteristike otpadnih voda (kvalitativne i kvantitativne), potreban stepen prečišćavanja i vrsta postupka biološke obrade predstavljaju polazne podatke za definisanje potrošnje vazduha. Određivanje potrošnje vazduha, sa aspekta utroška energije koji čini najveći udeo u troškovima rada ovih postrojenja, kao i efikasnosti procesa aeracije od koje zavisi i efikasnost celokupnog tretmana, predstavlja bitan faktor pri projektovanju jednog SBR reaktora.Wastewater treatment using biological process for cases of smaller capacities usually takes place in sequential batch reactors (SBR - Sequencing Batch Reactor). The paper discusses the method of defining air consumption in SBR plants for sanitary wastewater treatment in the biological process phase. The specificity of the SBR plant operation is the development of processes in cycles consisting of several phases, whereby in some phases aeration is performed by introducing air using a distributor - aerator. The characteristics of wastewater (qualitative and quantitative), the required degree of purification and the type of biological treatment process are the starting data for defining air consumption. Determination of air consumption, from the aspect of energy consumption that makes a larger share in the costs of plant operation, as well as the efficiency of the aeration process on which the efficiency of the overall treatment depends, is an important factor in designing an SBR reactor

State and ways further development in cheesemaking

Izvršena je sažeta analiza stanja industrijskog sirarstva u našoj zemlji i predviđanja daljih pravaca razvoja. Utvrđeno je da je naše sirarstvo postiglo relativno visok stepen razvoja i pored toga što u našoj zemlji nisu rešeni neki osnovni uvjeti, kao što su: količina i kvaliteta mlijeka, proizvodnja proteolitičkih fermenata za koagulaciju mlijeka, neke čiste kulture mikroorganizama i dr. Najbolji rezultati postižu se u specijaliziranim sirarskim pogonima. U daljem razvoju veću pažnju treba posvetiti istraživanju mogućnosti za industrijsku proizvodnju renomiranih domaćih vrsta sireva i povećanju rentabilnosti sirarske proizvodnje kroz veće iskorištavanje sastojaka mlijeka posredstvom ultrafiltracije i obrazovanja koagregata. Analizirane su prednosti i nedostaci ovih postupaka i postignuti rezultati u našoj zemlji.A concise analysis was made, concerning the state of industrial cheese making production in our country as well as the concept of further ways oj development. It has been stated that cheesemaking in our country has achieved a relatively high degree of development, in spite of basic problems in this^ industry that have not been solved, for example: the quantity and the quality of milk, the production of proteolitic enzimes for milk coagulation, microbiological culture problems and some other problems. The best results have been obtained in the specialized cheese making factories. In further development of cheesemaking more attention should be paid to searching the possibilities for industrial production of some renowned autochthonic cheese varieties, as well as to the improvement of cheese manufacture economics. The latter can be achieved by greater incorporation of milk components into cheese using the ultrafiltration process or the formation of protein coagregates, with subsequent coagulation. Advantages and disadvantages of these procedures, as well as the attained results in resolving the encountered problems in Yugoslavia, have been analyzed

The influence of heat treatment on the efficiency of milk nitrogen compounds recovery

Cilj ovih istraživanja bio je da se ustanovi utjecaj različitih režima termičke obrade na iskorištenje dušičnih tvari mlijeka. Rezultati istraživanja pokazali su da termička obrada na 95-97 °C omogućava znatno veće iskorištavanje dušičnih tvari mlijeka i da se ono kreću u prosijeku 94,7 %, što predstavlja povećanje od 10,82 %. Povećano iskorištenje dušičnih tvari posljedica je nastajanja koagregata bjelančevina mlijeka (kemijskog kompleksa između kazeina i nekih proteina mliječnog seruma) koji nastaju kao posljedica djelovanja korištene temperature od 95-97 °C u trajanju od 20 minuta.The aim of these investigations was to determine the influence of different thermal treatments of the efficiency of recovery (separation) of nitrogen compounds of milk in some, milk processing. This is done having in mind a lack of investigations in our country as well as the possibility of application in dairy technology. Skimmed milk was subjected to thermal treatment at 85 °C for 20 seconds and at 95-97 °C in the course of 20 minutes. The results obtained show clearly that the more severe heat treatment led to a much higher separation of nitrogen compounds at pH 4,6 and averaged 97,7 %. Compared with the recovery of nitrogen compounds from pasteurized milk under the same conditions, it was 10,82 % higher. The differences appear as the result of protein coagregates formation under the influence of the heat treatment at 95-97 °C for 20 minutes

Machine learning approach in inferring main population-level COVID-19 risk factors

Machine-learning methods have become indispensable in scientific research as the amount of available data has grown exponentially in recent years. It is, thus, necessary to employ various unsupervised and supervised machine learning methods to uncover the main determinants of COVID-19 transmissibility and severity in the population. Upon introducing appropriate disease transmissibility and severity measures and gathering relevant socio-demographic, environmental, and health-related data for the countries with obtained said measures, we implement several machine-learning-based approaches to select the most prominent drivers of disease transmissibility and severity. These approaches include regularization-based linear regression models and more advanced Random Forest and Gradient Boost methods, which are not limited to the linear relationships between the features and the response. Principal component analysis was used for preselection to avoid overfitting, where numerous features were considered for a relatively small number of observations (i.e., countries/states). As a result, a broad range of potential COVID-19 risk factors was reduced to several prominent features, selected robustly by different methods - we further untangle how they, directly or indirectly, contribute to the transmissibility and severity of the disease. Our results underscore the evolving nature of COVID-19, from the severity experienced during the first wave to the emergence of new, highly transmissible variants like Omicron. These insights can guide public health interventions, vaccine strategies, and policies aimed at reducing the burden of COVID-19 and effectively managing future waves and emerging variants.Book of abstract: 4th Belgrade Bioinformatics Conference, June 19-23, 202

Sweet creams and whey based spreads

Jedan od najhitnijih problema sadašnjeg čovječanstva jeste problem nedostatka hrane. Problem se postavlja zbog velikog porasta stanovništva i nedovoljne proizvodnje hrane u zemljama u kojima je baš i najveći porast stanovništva. U tom pogledu pored povećanja proizvodnje postavlja se i pitanje racionalnijeg iskorištavanja sastojaka hrane koja je već jednom proizvedena za potrebe čovjeka.The authors describe the production of sweet creams and whey based spreads with addition of ingredients (chocolate, lemon, fruits, or tomato concentrates, garlic and vinegar). Chemical composition of produced creams and spreads was checked, and their organoleptic quantities. Both, chemical composition and taste were found satisfactory

Improvement of the method for TS determination of yoghurt

Izvršena su istraživanja s ciljem da poboljšaju gravimetrijske metode određivanja suhe tvari u jogurtu, s obzirom na ranije utvrđene razlike između SM jogurta i SM mlijeka.These investigations were carried out starting from previously established facts that in the course of incubation and 24h storing of yoghurt appears a decrease of 0.14 per cent TS, as compared to the raw material, due to the differences in the SNF

Proizvodnja kiselo-mliječnih proizvoda sa maslačnom kulturom

Proizvodnja kiselo-mliječnih proizvoda je u stalnom porastu u svijetu i u nas. U našoj zemlji od kiselo-mliječnih proizvoda najviše se proizvode jogurt i kiselo mlijeko koji su zbog duge tradicije u ishrani i stvorenih navika masovno prihvaćeni. U njihovoj proizvodnji kao čiste kulture koriste se termofilne mliječno-kiselinske bakterije S. thermophilus i L. bulgaricus. Kiselo-mliječni proizvodi, kao kefir, acidofilno mlijeko i drugi su neznatno zastupljeni u našoj zemlji

Elektroforetsko razdvajanje himozina i pepsina iz različitih preparata sirila

U svijetu je uobičajeno da se preparati sirila deklariraju prvenstveno prema njihovoj aktivnosti u pogledu zgrušavanja mlijeka. U praksi se često podrazumijeva pod jačinom sirila aktivnost himozina, a gubi iz vida pepsin, koji je također prisutan u svim preparatima sirila

Attitudes of Primary School Teachers Toward Inclusive Education

Background: The aims of our study are related to examining the relevance of teachers' attitudes toward the implementation of inclusive education. In addition, its subject is related to the implications on inclusive education policies, limitations of the existing study along with the recommendations for our future research endeavors. Methods: The research is a cross-sectional study type. The sample included 64 primary school teachers in the lower grades of primary school (grades 1–4), selected by using simple random sampling, in three primary schools on the territory of Belgrade, Serbia in 2021 (26, 17, and 21 primary school teachers). The Questionnaire for Teachers, which was used as a research instrument, was taken from the Master's Thesis Studen Rajke, which was part of the project “Education for the Knowledge Society” at the Institute for Educational Research in Belgrade. Dependent variables measured in the study referred to the attitudes of primary school teachers toward inclusive education. Categorical variables are represented as frequencies and the Chi-square test was used to determine if a distribution of observed frequencies differed from the expected frequencies. Results: One in three teachers (32.8%) thought that inclusion was useful for children with disabilities (29.7%), of them thought that schools did not have the conditions for inclusive education, whereas one in four teachers (25.0%) believed that inclusion was not good. No statistically significant differences were found in the attitudes of professors, when observed in terms of their gender, age and length of service. Conclusion: Investing more resources and time in developing and implementing special education policies can promote successful inclusive education