Petar Dokic

University of Novi Sad · Faculty of Technology

BACKGROUND Knowledge about specific functional characteristics, such as viscosimetric, conductometric, tensiometric and structural properties of polysaccharide aqueous solutions is highly important in the successful and adequate application in food emulsion formulation. For the first time detailed characterization of sugar beet fibers aqueous solut...

Biopolymer-based stabilizers are becoming particularly favourable natural solutions for application in complex systems, such as O/W emulsions. Individual and combined impact of three polysaccharide-based stabilizers (sugar beet fibers, sugar beet pectin and OSA modified maltodextrin) on the formation and stability of corn oil-in-water emulsions was...

The objective of this study was to investigate the effect of oil phase concentration, at different emulsification conditions concerning homogenization time and emulsifier content, on droplet size distribution and stability of corn oil-in-water emulsions. Emulsions were prepared with 3, 5, 10, and 20% w/w triethanolamine oleate (calculated on oil am...

The demand for gluten-free products is ascending steadily, paralleling the increase in prevalence and incidence of celiac disease and other allergic reactions or intolerances to gluten consumption. The replacement of gluten presents a major technological challenge, as its visco-elastic properties largely determine the breadmaking performance of whe...

The pasting properties of alkali-isolated corn starches obtained from corn grits, as well as the rheological behaviour of their 8% gels were investigated. The alkali isolation was performed using different conditions concerning alkali concentration (0.15% and 0.30%), steeping time (30 min and 90 min) and temperature (25 °C and 50 °C).Alkali-isolate...

The influence of added xanthan gum on rheological and dispersion characteristics and stability of concentrated (50% w/w) corn oil-in-water emulsions, stabilized with 5% (percentage on oil amount) polyoxyethylene (20) sorbitan monooleate (Tween 80), have been investigated. Emulsion with no xanthan indicated coalescence and poor creaming stability. A...

The objective of this paper was to characterize commercially available octenyl-succinate starches (OSA starches), Purity Gum 2000 and Hi-cap 100, by determining their viscous behaviour and characteristics and molecular mass, as well as to examine their emulsifying properties in corn oil-in-water emulsion system. Huggins equation and extrapolation...

Abstract The objective of this paper was to characterize commercially available octenyl-succinate starches (OSA starches), Purity Gum 2000 and Hi-cap 100, by determining their viscous behaviour and characteristics and molecular mass, as well as to examine their emulsifying properties in corn oil-in-water emulsion system. Huggins equation and extra...

Measurement of yield stress is important in ensuring the quality of various food products, as well as in determining the optimal processing and handling conditions. However, due to the complex nature of food products (three-dimensional network microstructure) there is a difficulty in choosing the most appropriate test by which the determined yield...

Investigations of influence of surfactant-gelatin interaction on microcapsule characteristics were undertaken. In the first step of microencapsulation 20% (v/v) paraffin oil emulsions were prepared in the solution of SDS of different concentrations with 3.0 % of gelatin. Concentration of SDS was varied in order to provide both types of gelatin-SDS...

Stochastic model for oil emulsification in water has been deduced. The model in the form of differential equation was starting point to get various mathematical expressions and relations connecting different factors and parameters of the emulsification process and dispersion and Theological properties of the emulsion. Experimental investigations of...

Relation between viscous characteristics of different maltodextrins and degree of starch hydrolytic conversion expressed as DE value (dextrose equivalent) was deduced. Reduced viscosity of diluted solutions of maltodextrins linearly increased with maltodextrin concentration in the range 0.2×10−2 to 1×10−2 g/cm3. Values of intrinsic viscosity decrea...

The formation of phosphatidylcholine liposomes loaded with proanthocyanidins isolated from grape (Vitis vinifera L.) seeds was studied. Using scanning electron microscopy it was determined that the type and the size of the liposomes depend on various factors proanthocyanidin concentration and homogenization conditions (time and intensity). Rheolog...

Maltodextrins, low converted products of starch hydrolysis, are used in various emulsions to provide desirable viscosity, texture and mouthfeel.In order to assess behaviour of such emulsions in process of production (emulsification) as well as end products in application (pouring, spreading) it is necessary to investigate emulsification dynamics, g...

Effect of dextrose equivalent (DE) of maltodextrin present in continuous phase on flow along with dispersion properties of sunflower oil in water emulsions has been investigated. Both, rheological and disperse characteristics of the emulsions were greatly influenced by continuous phase viscosity and thus by the DE value of maltodextrin.. The smalle...

Many food, pharmaceutical, cosmetic and chemical products exist in the form of emulsions. A common problem with emulsions is their instability. One method of effective protection against coalescence of the particles is to raise the viscosity and lower surface tension by adding a polymer and low-molar-mass surfactant. Interaction between polymer and...

ABSTRACT In order to assess the effect of surfactant-polymer interactions on structure building in shear, rheological behaviour and the characteristics of corn oil in water emulsions, stabilised by triethanolamine oleat (TEAO) with and without addition of sodium carboxymethyl cellulose (CMC) have been investigated. Amphiphilic properties of carboxy...

SUMMARY: A systematic investigation of the procedure and conditions for paraffin emulsification in water by phase inversion method was undertaken in order to obtain stable technical emulsions and to find out what emulsifier properties, i.e. final emulsion characteristics and phase inversion are independent. The emulsions were stabilized by an emuls...

One of the most significant aspects of polymer-surfactant interaction, from the practical point of view, is that of rheology control and viscosity enhancement. In the oppositely charged polyelectrolyte-surfactant system strong ionic interaction often leads to precipitation of the formed complex yielding serious problems. In this paper the interacti...

Low converted products of enzyme and acid hydrolysis of starch, short chain polymer-maltodextrins were produced in well controlled laboratory conditions and together with some commercial industrial products have been tested. Molecular characteristics of these various maltodextrins, such as specific optical rotation, dextrose equivalent, degree of p...

The gelation process of mixed biopolymer solution under the shear rate was investigated. To this aim 3% solution of gelatin and sodium carboxymethylcellulose (NaCMC), with the gelation/NaCMC ratio 4/1 was prepared. Rheological measurements were performed using rotational viscometer with coaxial cylinders (“Haake”, Germany) at the temperature of 20°...

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Adsorption from solutions of sodium dodecylbenzene sulfonate (SDBS) and gelatin mixtures, on the dispersed paraffin oil droplets surface has been investigated. The adsorbed amount of SDBS and gelatin was estimated by the concentration determinations in the continuous phase, after the oil droplets were removed by centrifugation. From adsorption data...

The evaluation of the procedure for the determination of optimal parameters for the preparation of 0/W emulsions by the mechanical homogenizer has been studied. The method is based on a general functional dependence of the emulsion droplet-size distribution parameters on various factors (homogenization time interval, emulsifi-er concentration, and...

The influence of n-octanol on the particle size and particle size distribution of paraffin oil in water emulsions was investigated, by means of the equation derived for the dynamics of the homogenization process. Emulsions were stabilized with sodium dodecyl sulfate (SDS) and with different concentrations of n-octanol. Optimal concentration of n-oc...

Some investigations on the capability of differential scanning calorimetry (DSC) for the characterization of concentrated mineral oil in water emulsions indicated certain differences in their thermal behaviour depending upon various factors including particularly the emulsifier. In this paper DSC examinations were undertaken in order to assess the...

Droplet size and size distribution changes at homogenization of paraffin oil emulsions, stabilized by different concentrations of various emulsifiers, were investigated. During homogenization, samples were taken from emulsions and the most frequently occuring diameter, mean droplet diameter and standard deviation (distribution width) were determine...

Adsorption of sodium dodecylbenzene sulfonate (NaDBS) on the surfaces of dispersed oil globules during homogenization of paraffin oil in water emulsions has been studied. NaDBS concentration was changed over a wide interval comprising critical micelle concentration. For the emulsions homogenized for different time intervals the total quantity and t...

Summary Thermal induced phase inversion of concentrated oil-in-water emulsions stabilized by various fatty acid polyoxyethylene esters of sorbitan (Tween 21, Tween 61, Tween 65, Tween 80 and Tween 81) has been studied. Phase inversion temperature (PIT) was determined by differential thermal analysis and the changes in internal structure of emulsion...

Rheological measurements of the emulsions of paraffin oil in water, at concentrations of 10–70% were carried out. Emulsions were stabilized with various emulsifiers (Tween 20, Tween 40, Tween 60, Tween 65 and Tween 80, as well as Sodium dodecyl sulphate and Sodium paradodecyl benzene sulphonate with emulsifier- concentrations varying from 0.125 to...

Summary At the emulsions differing among themselves only by the particle size distribution, differences in viscous characteristics are due to different surfaces of dispersed phases. It is possible to evaluate mathematical terms relating theological characteristics with the parameters of Gamma particle size distribution in emulsions. The specific su...

In order to determine some colloidal characteristics that are of importance to the viscous and rheological behavior, β-lipoproteins of pig blood have been isolated. Viscosity of diluted β-lipoprotein solutions (concentrations less than 5 g/100 cm2) under different rates of shear was measured, and dependence between shearing stress and rate of shear...

Rheological characterization of starch gels is a complicated problem as the measured values represent only an apparent viscosity. They depend on shearing stress respectively shearing rate and thus also on the type of viscosimeter used. Moreover starch gels are thixotropic, which brings about additional difficulties in measuring procedures and repro...

The aim of this research has been the investigation of a general equation of the particle size distribution in emulsions, applicable to different emulsions, especially to particle size distribution at homogenization processes. It has been supposed that at homogenization particles tend to assume a characteristic, most probable diameterX, due to diff...

Urea and formaldehyde polycondensation was performed in shear and non shear condition under different pH values (3.5, 4, 4.5) and amounts of acetate buffer (0.14%, 0.41%, 0.69%). The reaction was ceased by changing pH from acidic to basic one when gel point was reached. This polycondensate represents a medium concentrated dispersion of polymer clus...

: A systematic investigation of the procedure and conditions for paraffin emulsification in water by phase inversion method was undertaken in order to obtain stable technical emulsions and to find out what emulsifier properties, i.e. final emulsion characteristics and phase inversion are independent. The emulsions were stabilized by an emulsifier m...