Vladimir S. Filipović

Modelling of factors influencing the effect of osmotic solution on reduction of selected microorganisms

The goal of this research is to model the effects of two osmotic solutions factors on the reduction of selected microorganisms, and to assess the application in osmotic dehydration process of animal raw materials from the aspect of microbiological safety.

Comparison of methods of zeta potential and residual turbidity of pectin solutions using calcium sulphate/aluminium sulphate as a precipitant

The affinity of calcium ion binding from CaO used in the most common process of purification of sugar beet juice is relatively low. Therefore, large amounts of this compound are required. This paper presents the theoretical basis of a novel sugar beet juice purification method based on the application of the binary system CaSO4/Al2(SO4) . In order to monitor the process of coagulation and precipitation of pectin in the presence of CaSO4/Al2(SO4)3, two methods were compared: measurement of the zeta potential and of residual solution turbidity. The zeta potential of pectin solution was determined by electrophoretic method, while the residual turbidity was determined by spectrophotometry. Two model solutions of pectin (0.1 % w/w) were investigated. Studies were performed with 10 different concentrations of the binary solution CaSO4/Al2(SO4)3 (50 500 g dm). The amount of the precipitant CaSO4/Al2(SO4)3 (1:1 w/w) needed to achieve the minimum solution turbidity and charge neutralization of pectin particles (zero zeta potential) were measured and compared. Colloidal destabilization occurred before a complete neutralization of the surface charge of pectin particles (zeta potential ~ 0 mV). Optimal quantities (490 705 mg g pectin) of the applied binary mixture, were obtained using both methods. This is much lower than the amount of CaO that is commonly used in the conventional process of sugar beet juice purification (about 9 g· g pectin). The use of these precipitants could be important from both economic and environmental point of view.

Quality of spelt pasta enriched with eggs and identification of eggs using 13C MAS NMR spectroscopy

This paper deals with the characteristics of spelt pasta enriched with eggs. Eggs were added to spelt farina in the quantity of 0, 124 or 248 g/kg (equivalent to 0, 3 or 6 eggs, respectively). Post-hoc Tukey’s HSD test at 95% confidence limit showed significant differences between various samples. Relatively low coefficients of variation have been obtained for each applied assay (1.25-12.42%), which confirmed the high accuracy measurements and statistically significant results. Standard score analysis is applied for accessing the contribution of eggs content to spelt pasta quality. Maximum scores regarding quality (0.89) and chemical characteristics (0.70), have been obtained for 6 eggs spelt pasta formulation. It is also shown that the presence of eggs in pasta can be clearly confirmed by 13C MAS NMR spectroscopy. Simultaneous increase in area of peak positioned at 29.5 and 176 ppm is directly associated with the increase in the content of added eggs in the corresponding samples. Pertinent data point at positive contribution of eggs to the spelt pasta and also that NMR spectrum can be used in the egg quantity control. [Projekat Ministarstva nauke Republike Srbije, br. TRI 46005 i br. TR 31029]

Re-use of Osmotic Solution OF OSMOTIC SOLUTION

In this paper the re-use of osmotic solution after osmotic treatment has been studied. A large amount of used osmotic solution remaining after the process is one of the major unsolved problems of osmotic treatment process. This problem has both ecological and economic aspects that should be concerned.Pork meat cubes were treated in three different osmotic solutions diluted with distilled water (R1 -sugar beet molasses, R2 – solution of salt and sucrose and R3 - combination of R1 and R2 solutions in a 1:1 mass ratio). Osmotic process has been observed during 5 hours, at temperature of 35oC and atmospheric pressure. Osmotic treatment has been performed simultaneously in concentrated solutions and diluted solutions (dilutions were obtained by mixing the solution and water in the mass ratio of 7:1 and 3:1). Parameters monitored during osmotic treatment were: dry mater content (DMC), water loss (WL), solid gain (SG) and osmotic dehydration efficiency index (DEI).Maximum values of these parameters were obtained in the dehydration with concentrated solutions, while recorded values in diluted solutions were much lower.The results show that the least effect on the osmotic process efficiency, when the osmotic concentration is lowered, has been observed for solution R3. This conclusion indicates that molasses is good osmotic solution with the possibility of re-using in successive processes of osmotic dehydration, with minimal treatment of reconstitution to original values of concentration.

Breadmaking characteristics of dough with extruded corn

Extrusion cooking is a thermal process often practiced in food, chemical and feed industry. Due to extrusion, nutritive value, texture, sensor characteristics and hygiene are improved. The influence of extruded corn grain and bread improver quantity on rheological and sensory characteristics of bread was investigated in this paper. Experiment was planed according to factorial plan 32 with independent variables: Quantity of extruded corn (10-30 % based in wheat flour, variation interval 10) and improver (0-0.4 % based on flour, variation interval 0.2). The influence of extruded corn on Dough handling is illustrated by extensigraph data: In comparison to the dough without corn, area is decreasing 50 to 60 % and resistance to stretching 15 to 20 %. The addition of commercial bread improver, regardless the quantity of extruded corn is beneficial contributing to improved extensigraph data up to 30 %. By substituting wheat flour with 10 to 20 % of extruded corn along with proper quality of bread improver, bread quality is satisfying and stalling is significantly improved. In the production of so-called mixed corn bread (30 % of extruded corn) extrusion is contributing to retard stalling and prolonged shelf-life.