Mariya Dushkova

University Of Food Technology - Plovdiv | UFTP · Process engineering

One main objective of this study was to increase the utilization of raw material in the rose (Rosa damascena Mill.) essential oil industry by the application of membrane technologies. In this research, distilled (dearomatized) rose petals, the primary byproduct in essential oil production, were subjected to an enzyme-assisted extraction and subsequ...

The energy consumption increases continuously around the world. The development of energy-saving processes is essential in order to environmental protection and application of green technologies. The purpose of this work was to investigate the effect of the transmembrane pressure (0.2 MPa to 0.5 MPa), the feed flow rate (190 to 330 dm3/h) and the v...

The energy consumption increases continuously around the world. The development of energy-saving processes is essential in order to environmental protection and application of green technologies. The purpose of this work was to investigate the effect of the transmembrane pressure (0.2 MPa to 0.5 MPa), the feed flow rate (190 to 330 dm3/h) and the v...

Lavender (L) and Rosa damascena (RD) industrial solid by-products were used as biodegradable adsorbents for the removal of the azo dye Acid Orange 7 from aqueous solutions. The equilibrium for the adsorption (1 g of adsorbent, 20 mL aqueous solution of dye, pH 7.05) occurred at the 60 min and at 100 mg/L initial concentration of azo dye. The adsorb...

Fennel (Foeniculum officinale Mill. var. dulce Mill) is an annual aromatic plant of the Lamiaceae family. Its fruits are processed to obtain essential oil for use in the food industry and cosmetics. The physical parameters of the fruits, i.e. length (5.50-8.00 mm), width (1.50-2.00 mm), volume of 100 fruits (1.36 × 10-6 m3), density of 100 fruits (...

One main objective of this study was to increase the utilization of the raw material in the rose (Rosa damascena Mill.) essential oil industry by application of membrane technologies. A new ultrafiltration-based process for green recovery of polyphenols from distilled (de-aromatized) rose petals, the primary by-product in essential oil production,...

In this experimental work, the microbiological, physicochemical, organoleptic, and rheological properties of yoghurts produced by ultrafiltered goat’s milk using two volume-reduction ratios and three probiotic starters were studied. It was established that the dry matter, fats, proteins, count of lactic acid bacteria, titratable acidity, and dynami...

In this experimental work, the microbiological, physicochemical, organoleptic and rheological characteristics of probiotic Bulgarian yoghurts produced by ultrafiltration of goat’s milk using different volume reduction ratio (2 and 3) and several probiotic starters (MZ2f, MZ2f + Bifidobacterium bifidum BB – 87, MZ2f + Lactobacillus acidophilus LAB –...

Citation: Dushkova, M.; Ivanova, M.; Trublet, L.; Petkova, Z.; Teneva, O.; Miteva-Petrova, M.; Desseva, I.; Mihaylova, D. Flux Behaviour, Rejection and Concentration Factors, and Energy Demand during Ultrafiltration of Sweet Buttermilk. Appl. Sci. 2023, 13, 3804. https:// Abstract: This work aimed to study the flux behavior, rejection and concentra...

The purpose of this work was to study the effect of pumpkin flour (10% and 20%), moisture content of initial mixture (14% and 20%) and working screw speed (180 min-1 and 220 min-1) on the physicochemical (expansion, density, hardness, colour) and sensory characteristics of rice extrudates enriched with pumpkin produced on a single screw extruder. T...

In this research, the possibilities of applying the extrusion process to produce functional food from quinoa enriched with goji berries were studied. The physical (expansion ratio, bulk density, hardness, and specific mechanical energy) and functional (water solubility index, water absorption index) characteristics were determined and optimized by...

The aim of the present work was to study the potential of ultrafiltration with three polyacrylonitrile membranes (1, 10, and 25 kDa) to concentrate polyphenolic antioxidants in apple juice and extract. The permeate flux, total polyphenols, polyphenolic profile, phenolic acid content, and total antioxidant capacity were determined using the FRAP and...

The equilibrium moisture contents (EMC) of deproteinized rapeseed meal (DRM) and model extrudate, prepared from DRM and corn grits (1:1), were determined at different temperatures (20 °C, 30 °C, and 40 °C) and water activities (0.112 to 0.851) by using the static gravimetric method. The model extrudate exhibited lower sorption capacity and signific...

The purpose of this study was to investigate the microbiological (number of viable lactic acid bacteria and bifidobacteria), physicochemical (dry matter, protein and fat contents, titratable acidity, and pH), and sensory characteristics (appearance of coagulum, taste and aroma, structure at cutting, color, and consistency at shattering) of probioti...

This experimental work aimed to study the effect of volume reduction ratio on the concentration and retention (selectivity) factors during ultrafiltration of goat’s milk with UF25-PAN polyacrylnitrile membrane. They were calculated on the basis of dry matter, totoal protein, fat and ash content in retentates and permeate at volume reduction ratios...

Kodinova, S. & Dushkova, M. (2021). Investigation of the flux, selectivity and concentration factor during ultrafil-tration of goat's milk. Bulg. J. Agric. Sci., 27 (2), 403-409 Combined effect of the working pressure, the feed flow rate and the volume reduction ratio on the flux during ultrafiltra-tion of goat's milk with a polyacrylonitrile membr...

Introduction. This research aims at determining the effect of canola oil and natural antioxidant of basil on chemical and sensory properties of fresh cheese. Materials and methods. A fresh spreadable cheese was prepared by the use of fresh whole milk, canola oil and natural antioxidant of basil. The prepared cheese was analysed on fatty acid profil...

Ultrafiltration of skim cow’s milk with a UF10-PAN membrane at volume reduction ratios (VRRs) of 2 and 3 was performed. The ultrafiltration retentates obtained were used for production of probiotic yoghurts with three different starters. A control sample was prepared using skim cow’s milk. All yoghurts were analysed according to the following param...

This experimental investigation aimed to establish the energy demand depending on the working pressure (0,2 MPa and 0,5 MPa), the feed flow rate (190 dm ³ /h and 330 dm ³ /h) and the volume reduction ratio (2 and 4) during ultrafiltration of goat’s milk by membrane with molecular weight cut-off 10 kDa. The energy demand increased with the rise of a...

In this experimental work, the energy demand at different pressures (0,2 MPa and 0,5 MPa), the temperature (20 °C and 50 °C) and the cow’s milk fat (0,1 % and 3,6 %) during ultrafiltration by membranes with different membranes - 10 kDa and 25 kDa, was investigated. The lower values of energy demand were established at lower pressure, fat and higher...

The aim of this experimental work was to investigate the dependance of the flux of UF10-PAN membrane with molecular weight cut-off 10 kDa on the working temperature at operating pressures 0.2 MPa, 0.35 MPa and 0.5 MPa during ultrafiltration of whey from Kashkaval at the begining of the process at a volume reduction ratio VRR = 2 and at the end of t...

Introduction. The effect of hydrocolloids (xanthan gum and guar gum) on dough properties and the quality of gluten-free bread from rice and corn flour enriched with whey protein concentrate was studied. Materials and methods. For the preparation of the whey protein concentrate it was used a laboratory system with a removable flat membrane module, e...

The aim of this experimental work was to investigate the dependence of the flux of UF10-PAN membrane with 10 kDa molecular weight cutoff on the working pressure of 0.2 MPa, 0.3 MPa, 0.4 MPa and 0.5 MPa at feed flow rates of 190, 260 and 330 dm 3 .h-1 at different volume reduction ratios (VRR = 2 and VRR = 4) during ultrafiltration of goat's milk. T...

A lactic acid beverage fortified with ground goji berries has been developed. The sequence of technological operations, the chemical, microbiological, organoleptic profile and antioxidant activity of the product during cold storage have been established. No statistically significant differences (ρ ≤ 0.5) characterizing the rate of the lactic acid p...

UF10-PAN membrane with molecular weight cutoff 10 kDa was used to investigate the process characteristics during ultrafiltration of whey from Kashkaval production. Dry matter, protein and mineral substances contents in retentates and permeate were analyzed at volume reduction ratio 2, 6 and 10. On this basis, retention and concentration factors wer...

Diafi ltration of ultrafi ltration retentate from whey was carried out with a UF10-PAN polyacrylnitrile membrane with 10 kDa molecular weight cut-off at different operating conditions (working pressure, volume reduction ratio and temperature). The multifactorial model created and the response surfaces for the effect of the three investigated factor...

Combined effects of working pressure, volume reduction ratio and feed flow rate on the flux during ultrafiltration of strawberry extract were studied depending on the molecular weight cut-off (1, 10 and 25 kDa) of polyacrylonitrile membranes. The mathematical models and response surfaces obtained demonstrate the highest flux values at high levels o...

The rheological characteristics of extrudates from corn semolina and mixture of corn semolina and tapioca flour were examined by rotational viscometer "Brookfield” RV-DV II + Pro. A non-linear relationship between the shear stress and the shear rate was established. The model of Ostwald–de Waele was applied and flow and consistency indexes were cal...

Combined effects of working pressure, temperature and fat content on the flux during ultrafiltration of cow’s milk with a polyacrylonitrile membrane UF10-PAN through full factorial experimental design were studied. Multi-factorial mathematical model for the influence of working pressure, temperature and fat content of milk on the flux was created....

The chemical composition of extract from the Bulgarian essential oil bearing plants from Lamiaceae family-oregano (Origanum heracleoticum L.) by extraction with C 2 H 2 F 4 (1,1,1,2-tetrafluorethane) was analyzed using GC and GC/MS. The main compounds (concentration higher than 3 %) of extract was as follows: carvacrol (70.05 %), p-cymene (11.83 %)...

In this paper, yoghurts from ultrafiltered concentrated whole milk with a volume reduction ratio 0, 2 and 3 with three different probiotic yoghurt starters were obtained. Their physiological, microbiological and rheological properties were examined. The concentrated probiotic yoghurts had high concentration of viable cells of the probiotic strain L...

Equilibrium sorption isotherms of extruded feed for carp stocking material in three variants were experimentally obtained. The study was conducted by the static gravimetric method at 20°C and water activities from 0.11 to 0.85. It was established that the isotherms have a typical S-shaped profile and there are no statistically significant differenc...

Blends of goji berry and rice flour were extruded in a laboratory single screw extruder (Brabender 20 DN, Germany). Effects of goji berry content, feed moisture content, and final cooking zone temperature on textural properties of the extruded products were studied. Full factorial experiment with combinations of goji berry content (5, 10%), moistur...

Blends of goji berry and rice flour were extruded in a laboratory single screw extruder (Brabender 20 DN, Germany). Effects of goji berry content, feed moisture content, and final cooking zone temperature on colour of the extruded products were studied. Full factorial experiment with combinations of goji berry content (5, 10%), moisture content (14...

The effect of the quantity of Goji berry (Lycium barbarum L.), the moisture content of product and the temperature in the third zone of the extruder on the density and expansion index of extruded products from rice and goji berry was investigated. The study was conducted using a single screw extruder “Brabender”20 DN. The results showed that the qu...

Extrusion of rice flour and dried fruit of goji berry using a single screw laboratory extruder " BRABENDER 20 DN " was carried out. Full factorial experiment was used to investigate the effect of the quantity of goji berry, the moisture of the material and the temperature of the matrix on the water absorption index (WAI) and water solubility index...

Extrusion of corn semolina with added dry whey protein isolate using a single screw laboratory extruder "BRABENDER 20 DN" was carried out. The effect of the amount of added whey protein and moisture content of the mixture on the density and expansion index using a full factorial experiment was investigated. The initial moisture content had the most...

An investigation was made which aimed to establish the dry matter, protein and fat con-centration factor and protein retention coefficient in retentates obtained by ultrafiltration of skim cow milk and protein/fat standardized cow milk intended for classic Bulgarian white brined cheese production. The skim and standardized milk ultrafiltration was...

In the present investigation the effects of moisture and goji berry’s content on the mass flow rate were studied. Extrusion was carried out on a single-screw laboratory extruder Brabender20 DN, Germany, with: diameter of the nozzle 3 mm; compression ratio 3:1; speed of the feeding screw 30 min-1 and the extruder screw 200 min-1; temperature zones i...

The possibilities for use of olive oil and basil’s extract in the production of fresh cheese were investigated and investigation of fatty acid composition of olive oil and the obtained cheese was carried out. It was established that the olive oil is characterized by a high content of unsaturated fatty acids, and high oxidative stability. The obtain...

Исследованы эффекты режимов пастеризации и количества сычужного фермента на процессе сычужно-кислотной коагуляции для получения свежего высокожирного сыра с добавлением кукурузного масла. Разработаны математические модели о влияние температурных режимов 82–88С0/5 min и количестве сычужного фермента l-5ml/100 l по показателям жирности и сухого вещес...

The possibilities for use of walnut oil and cardamom in the production of fresh cheese with spreadable consistency were studied. It was established that the walnut oil is characterized by a high content of essential ω-fatty acids. The results, obtained for the oxidative stability index of walnut oil, require the use of antioxidant cardamom. The fin...

The aim of this work is to research the possibilities for inclusion of sunflower protein concentrate "Sunpro" as an alternative to fish meal in the carp feed and investigate the product characteristics-density and the expansion index of extruded fish feed. The results show that the increase of the amount of sunflower protein concentrate "Sunpro" le...

The product charactersistics (sectional expansion index, density, water absorption index, water solubility index) of corn extrudates enriched with Goji berry (Lycium barbarum L.) in proportion of 5 and 10 % were investigated. The obtained results show that the sectional expansion index increased when the quantity of Goji berry increased, while the...

Whey diafiltration was carried out with a UF25-PAN polyacrylnitrilic membrane with 25 kDa molecular weight cut-off at volume reduction factors (VRF) VRF=2, VRF=4, VRF=6, VRF=8, VRF=10. The values of the principal components dry matter, protein, lactose and mineral substances in the retentates and permeate obtained were established. The relative sha...

Continued growth and intensification of aquaculture production depends upon the development of sustainable protein sources to replace fish meal in aquafeeds. The plant feedstuffs considered include oilseeds, legumes and cereal grains, which traditionally have been used as protein or energy concentrates as well as novel products developed through va...

The purpose of the present study was to explore the effects of feed moisture and the addition of whey protein isolate on some physicochemical properties of the obtained extrudates from potato flakes. Extrudates were produced using a laboratory single-screw extruder. Conditions during extrusion were: screw speed -200 rpm; compression ratio -3:1; ext...

The rennet coagulation process of whole pasteurized cow's milk and ultrafiltration (UF) retentates obtained from it at volume reduction factors VRF=1.5, VRF=2, VRF=3 was monitored. The diffuse reflectance profiles over a one-hour period were obtained using an optical device measuring the reflectance ratio at 950 nanometers. The results showed simil...

The effect of ultrafiltration and diafiltration of whey from kashkaval, and of reverse osmosis of the ultrafiltration permeate on several ecological indices, i.e. chemical oxygen demand (COD permanganate oxydability), chemical oxygen demand (COD bichromate oxydability), 5-day biological oxygen demand (BOD 5) and undissolved substances was investiga...

Whey ultrafiltration was carried out with a UF25-PAN polyacrylnitrilic membrane with 25 kDa molecular weight cutoff at volume reduction factors (VRF) = 2, VRF = 3, VRF = 4 and VRF = 5. The values of the principal components dry matter, protein, fat, lactose and mineral substances in the retentates and permeate obtained; the relative share of protei...

The aim of the present investigation was to determine experimentally the effects of transmembrane pressure and volume reduction factor on the flux of a UF25-PAN polyacrylnitrilic membrane under ultrafiltration and diafiltration of skim and whole whey obtained from Kashkaval hard cheese. The experiments were carried out under the following operating...

DINKOV, K., M. DUSHKOVA and N. TOSHKOV, 2008. Regression models for density and viscosity of ultrafiltration milk concentrates. Bulg. J. Agric. Sci., 14: 542-548 Ultrafiltration of skim and standardized milk was carried out with a UF25-PAN polyacrylnitrilic membrane with 25 kDa molecular weight cut-off at volume reduction factors VRF=2, VRF=3, VRF=...

The aim of the present research was to determine experimentally the rennet coagulation and rheological properties of milk gels from standardized pasteurized milks at the following temperature/time combinations: 70°C for 10-15 min, 80, 85 and 90°C for 1 min each. The results showed that the gelation time of milk pasteurized at the previously mention...