Bojana Ikonić

The fractionation of natural coagulant extracted from common bean by use of ultrafiltration membranes

Abstract In the age of rapid degradation of environment, the use of natural coagulants for water and wastewater treatment represents a promising idea which is in line with the global sustainable initiatives. Since these coagulants are of organic nature and have complex composition, it is important to separate components which show coagulation activity from those which do not show. In this work, ultrafiltration membranes with MW cut off of 10,000 Da and 30,000 Da were used for fractionation of natural coagulant extract obtained from common bean seed. Coagulation efficiency of these fractions was assessed by jar tests in model water. Coagulation conditions (pH and applied dose of coagulant) were optimized for each fraction. The fraction of extract with molecular weight lower than 10,000 Da was showed as the best coagulant with coagulation efficiency more than 40% at pH 10 and applied dose 2.5 ml/l.

Flux Improvement during Cross-flow Microfiltration of Wheat Starch Suspension using Turbulence Promoter

The objective of this study was to investigate the effects of the process variables (transmembrane pressure, flow rate, and concentration) on the permeate flux during the microfiltration of model starch suspensions, and to determine the conditions under which the use of Kenics statics mixer as a turbulence promoter is justified. A response surface methodology was used to examine the influence of the selected operating conditions on starch suspension microfiltration using a single channel ceramic membrane with 200 nm pore size. The experimental results clearly show that the improved performance of starch suspension cross-flow microfiltration can be obtained by using a Kenics static mixer, especially at lower flow rates. Compared to the operation without the turbulence promoter, the average permeate flux improvement during the filtration period ranged from 30% to 230%. As a result of the statistical analysis, the optimal conditions for starch suspension microfiltration were determined and applied to microfiltration of starch industry wastewater.

Effect of Starter Culture Addition and Processing Method on Proteolysis and Texture Profile of Traditional Dry-Fermented Sausage Petrovská klobása

Proteolysis and texture profile of Petrovská klobása, made with addition of starter culture, were investigated during the ripening in different conditions (traditional versus industrial). Due to intensive degradation of myofibrillar proteins, significant increases of non-protein nitrogen and free amino acids nitrogen contents were registered in all samples. Similar proteolytic changes were found in both starter and non-starter sausages, but were more pronounced in samples ripened in industrial room. In relation to ripening conditions hardness and chewiness differed significantly, while starter culture had significant effect only on hardness of sausages processed in industrial room.

MATERIAL AND ENERGY FLOW MANAGEMENT- LIFELONG LEARNING COURSES EXPERIENCES

Material and energy flow management is among the most important factors for the economic growth of a society in harmony with nature and it will play the main role only in the area of sustainable development. The three lifelong learning courses were developed in order to introduce this concept to the industry professionals and administration at the city and regional level. The main goal was to heighten awareness of participants to this topic, as in Serbia it is relatively new approach in corporate and administrative management. The results of the courses confirmed the interest in this kind of lifelong learning courses with suggestion to join it in a single course with emphasise on the specific participant’s problems.

Drying characteristics of traditional fermented sausage Petrovská klobása: The effect of different ripening conditions and use of starter culture

A study was carried out on traditional Serbian dry-fermented sausage Petrovska klobasa in order to investigate the effect of different ripening conditions and use of starter culture (SC) on drying characteristics of this typical meat product. The results related with reduction of diameter, water activity (aw) and moisture content of sausages, obtained during ripening, indicated 30 days faster drying process in controlled industrial ripening room (RR) than in traditional room (TR) (60 vs. 90 days). Along with the ambient (thermo-hygrometric) conditions, this phenomenon was also determined by pH, which was lower in RR sausages (P 0.992) indicate good fit of the experimental data (average moisture content vs. drying time) using third degree polynomial equation, both for RR and TR sausages, whether the samples were produced with or without SC. Additionally, the evolution of moisture content ratio between internal and external fractions of sausages indicated more intense drying in the external ones. This was particularly pronounced in sausages made with SC after 30 days of drying. The use of SC and RR in processing of Petrovska klobasa seems to be a potential technological improvement to shorten the drying period and to prolong the production season of this traditional meat product.

Primena višekanalne keramičke membrane u mikrofiltraciji suspenzija skroba

This work investigates influence of different process parameters such as transmembrane pressure, flow rate and concentration of wheat starch suspension on the average permeate flux and permeate flux decline. Used membrane in all experiments was 19 channels ceramic membrane with 0.2 μm pore size. Experimental results were analyzed using response surface methodology. It is observed that the significant average permeate flux enhancement of 200% was achieved by the increase of the transmembrane pressure, while the increase of flow rate and concentration affected the increase in average permeate flux in the range of 40-100%. Permeate flux decline was almost independent of the transmembrane pressure, but the increase of the flow rate, as well as the decrease of the concentration led to decrease of permeate flux decline in the range of 20-50%.