Marta Tomczyńska-Mleko

New product development: Cellulose/egg white protein blend fibers

The aim of the research was to form mixed cellulose/egg white isolate (EWI) fibers. Cellulose was dissolved in the Schweitzers reagent. The blend fibers were obtained by simultaneous cellulose fiber formation and acid-induced gelation of EWI in 33% sulphuric acid solution. Increased storage modulus was noted for the blend fibers in comparison to the cellulose fibers. EWI alone formed fibers which were composed of microfibers with the average diameter of about 80 nm. Cellulose fibers had a loose microstructure with about 10 μm gaps and rough surface. The addition of EWI caused that the surface of the fiber was even more rough with a tendency to form microfibers, which were not observed for cellulose alone. EWI protein molecules had the tendency to bridge the voids between cellulose microfibers. Protein in the blend fibrils formed more branched aggregates than in the EWI fibrils, which was probably caused by interactions with copper ions. Both in cellulose and cellulose/EWI fibrils, the cellulose crystallized in cellulose II monoclinic system. Reduction in COH groups was noted, which was probably caused by interactions between the cellulose and proteins molecules. EWI/cellulose interactions caused formation of β-sheet type structures.

The effect of pH and modified maize starches on texture, rheological properties and meltability of acid casein processed cheese analogues

The objective of this study was to investigate the influence of pH on texture, rheological properties and meltability of processed cheese analogues obtained using acid casein (AC) at 11, 12 or 13xa0% concentration or using 10xa0% AC with 1, 2 or 3xa0% acetylated distarch adipate (ADA) or hydroxypropyl distarch phosphate (HDP). Hardness, adhesiveness, cohesiveness and viscosity increased with protein or starch concentration. The increase in complex viscosity (η*) was greater for samples contained ADA than HDP. In general, starch-containing cheese analogues exhibited more viscous properties (tan δxa0>xa01) in higher pH values (6.0–7.0) and more elastic properties (tan δxa0<xa01) in lower pH values (4.5–5.5). All processed cheese analogues obtained at pH 5.0–7.0 presented good melting characteristics. These various characteristics analysed in the present study may ensure the valuable information for obtaining cheeses with proper textural/rheological properties and meltability.

Hard Biodegradable Biopolymer Obtained from Whey Protein Concentrate and Montmorillonite

The aim of this study was to obtain whey protein concentrate—WPC/montmorillonite—MON biopolymers. Mixed whey protein/montmorillonite biopolymers were formed as heat-induced gels and hardened by water evaporation. Increase in protein concentration caused an increase in storage and loss moduli of the gels. Adding 5xa0% of MON to whey protein gel matrix caused an increase in the moduli value. Obtained biopolymers behaved as weak physical gels as loss tangent was in a range 0.25–0.45. Increase in protein concentration and addition of MON caused increase in viscosity of the biopolymers measured by dissipation of ultrasound vibrations. Addition of MON generally caused reinforcement of the structure of the mixed gels and the material was more resistant to puncture. Addition of MON caused changes in the microstructure of whey protein gel, which became more fine-stranded. It was probably caused by adsorption of the ions by MON. Drying of WPC/MON gels caused formation of very hard biopolymer, which can be applied as natural biodegradable material.

Surface Properties of Aerated Ion-induced Whey Protein Gels

Aerated whey protein gels were formed using calcium chloride, magnesium chloride or iron (II) chloride induced gelation of pre-denatured protein dispersions. The structure of the obtained gel surface depends on the type and concentration of added salt. Higher cation concentration produced gels a with higher quadratic mean of the surface roughness and maximum roughness height. Aerated gels of optimal properties for retaining air bubbles were characterized by similar surface roughness. The surface topography is mainly responsible for changes in the wettability. The contact angle of the probe liquid sample depends on the liquid surface tension components. An approach based on the contact angle hysteresis (CAH) is suitable for determining the total value of the apparent surface free energy of such materials. An approach based on the components of apparent surface free energy (LWAB) only allows the calculation of the dispersion component and electron donor parameter of energy in the case of added magnesium and iron salt. Wettability, depending on the nature of the surface, can be described for the hydrophilic surface by the Wenzel model, and for the hydrophobic surface by the Cassie – Baxter model.

Ternary Biopolymer Based on Wheat Gluten, Whey Protein Concentrate and Montmorillonite

The aim of the research was to obtain biopolymers based on wheat gluten, whey protein concentrate (WPC) and montmorillonite (MON). Ternary biopolymers were formed as heat-induced gels and they were hardened by water evaporation. Adding 7xa0% of MON and 5xa0% WPC to gluten caused ca. four times higher values of storage modulus. Increased moduli values with adding MON and WPC to gluten were probably caused by reinforcing effect of MON, which decreased mobility of gluten chains and possible interactions between gluten and whey proteins by disulphide interchange. Increase in gluten protein concentration and addition of WPC and MON caused increase in viscosity measured by dissipation of ultrasound vibrations. Evaporation of water from the gels formed very hard material with high puncture force values. Obtained gels were very plastic and it was easy to form any type of shapes. They could be used to produce biodegradable pottery (e.g. flowerpots) with the mechanical properties similar to non-degradable clay products.

New controlled release material: aerated egg white gels induced by calcium ions

The aim of the research was to use low-mineral egg white albumin isolate to obtain aerated calcium ion-induced gels and to investigate their aptitude as matrices for active ingredients release. Aerated gels were prepared by adding calcium ions to pre-heated protein dispersions with simultaneous aeration. 20xa0mM calcium concentration was an optimal concentration at which the maximum viscosity and hardness of the gels were found. For higher concentrations of calcium ions (25–30xa0mM), aerated gels were characterized by lower values of the moduli and tangent of the phase angle was larger for aerated gels which indicated more viscous character than that of non-aerated gels. Increased ions concentration causes higher aggregation of protein matrix and less smooth microstructure of the interface between the gel and air. An increase in calcium concentration from 5 to 30xa0mM caused an increase in an average bubble size. The release of calcium ions from aerated gels was measured in an artificial stomach. It occurred by Fickian diffusion through the swelling matrix and it was faster for the gels with higher concentration of calcium. An increase in calcium concentration caused an increase in surface roughness of the aerated gels. There were linear correlations between the quadratic mean of the surface roughness and “n” coefficient from the Ritger and Peppas equation and between the maximum roughness size and “n”. The increased calcium concentration made the gel microstructure more particulate and the surface rougher, which enabled faster proteolysis of the gel in an artificial stomach and faster diffusion of calcium ions.

The extrusion test and sensory perception revisited: Some comments on generality and the effect of measurement temperature

Relations between sensory perception, extrusion and fracture in shear, extension and compression are examined. Gelatin-based gels are perceived as less firm and less hard than expected based on their mechanical properties compared to polysaccharide gels that have the same mechanical properties at room temperature but melt well above body temperature, underlying the importance of the measurement temperature for gels that melt during mastication. Correlations between parameters from extrusion and compression, extension and shear are verified using mixed polysaccharide gels.nnnPRACTICAL APPLICATIONSnWe previously reported a high correlation between several sensory attributes and parameters from an extrusion test. The extrusion test showed the most robust correlation, and could be used to assess samples at both extremes of the texture range with respect to elasticity, for example, both samples that could not be extended as their very low elasticity led to their fracture during handling, as well as samples that could not be fractured in compression. Here, we reexamine the validity of the relations reported. We demonstrate the generality of the relations between large deformation tests and extrusion, but the findings underscore the need to take into account the measurement temperature for samples that melt during mastication when correlating instrumental parameters with sensory perception.

Surface tension and wetting properties of rapeseed oil to biofuel conversion by-products

Abstract This work presents a study on the surface tension, density and wetting behaviour of distilled glycerol, technical grade glycerol and the matter organic non-glycerin fraction. The research was conducted to expand the knowledge about the physical properties of wastes from the rapeseed oil biofuel production. The results show that the densities of technical grade glycerol (1.300 g cm-3) and distilled glycerol (1.267 g cm-3) did not differ and were significantly lower than the density of the matter organic non-glycerin fraction (1.579 g cm-3). Furthermore, the surface tension of distilled glycerol (49.6 mN m-1) was significantly higher than the matter organic non-glycerin fraction (32.7 mN m-1) and technical grade glycerol (29.5 mN m-1). As a result, both technical grade glycerol and the matter organic non-glycerin fraction had lower contact angles than distilled glycerol. The examined physical properties of distilled glycerol were found to be very close to that of the commercially available pure glycerol. The results suggest that technical grade glycerol may have potential application in the production of glycerol/fuel blends or biosurfactants. The presented results indicate that surface tension measurements are more useful when examining the quality of biofuel wastes than is density determination, as they allow for a more accurate analysis of the effects of impurities on the physical properties of the biofuel by-products.

Effect of gluten on the properties of ternary biopolymers based on gluten, whey protein concentrate, and kaolinite

The aim of the research was to investigate the effect of different gluten (Gl) concentration on ternary biopolymers with whey protein concentrate (WPC) and kaolinite (KAO). Distilled water dispersions of Gl (10–30%), WPC (7%), and KAO (5%) were heated at 80xa0°C for 30xa0min. The concentration of WPC and KAO was based on previous research with montmorillonite. Rheological properties of produced wet biopolymers were evaluated by dynamic rheology and ultrasound viscometry. The obtained biopolymers were dried in the thermostatic cabinet for 24xa0h at 45xa0°C. The texture was determined using the puncture test and the microstructure was analyzed by scanning electron microscopy. Surface properties of dried biopolymers were analyzed by surface wettability and roughness measurements. The increase in gluten concentration caused an increase in moduli and viscosity of the obtained wet biopolymers and in the puncture force for dry biopolymers. For the ternary biopolymer, layers with intercalation and exfoliation are observed in comparison with the biopolymer obtained without KAO. With the increasing Gl content in the biopolymer, the number of surface hydrophobic groups with carbon decreased and the number of surface hydrophilic groups increased. Higher Gl concentration produced less porous structure, although there are differences in the micro and nano-scale roughness. Water contact angle decreased with the increased Gl concentration, which is in agreement with less porous microstructure of the surface. The apparent surface free energy increased with the increasing of Gl concentration. The best plastic properties and the best shape of a pot were obtained for the ternary biopolymer with the 15% Gl concentration.

Viscoelastic Properties of Soil with Different Ammonium Nitrate Addition

Four different soils samples were taken from not cultivated recreational places. Particle-size distribution and pH (in water and in 1 M KCl) of the soil samples were measured. Soil samples were saturated with deionized water and solution of ammonium nitrate with the concentration of 5, 50 or 500 mM for 3 days. The samples were analyzed using dynamic oscillatory rheometer by frequency and strain sweeps. Soil samples were similar to physical gels, as they presented rheological properties between those of a concentrated biopolymer and a true gel. 50 mM concentration of the salt was enough to make changes in the elasticity of the soils. Small concentration of the fertilizer caused weakening of the soil samples structure. Higher concentration of ammonium nitrate caused the increase in the moduli crossover strain value. For the loam sample taken from a playground, with the highest content of the particles <0.002 mm (clay aluminosilicates), the lowest value of strain was observed at the moduli intersection. Lower strain value was necessary for the sliding shear effect of soil A sample effecting transgression to the “flowing” state. Strain sweep moduli crossover point can be used as a determinant of the rheological properties of soil.