Sven Karlović

Improving the controlled delivery formulations of caffeine in alginate hydrogel beads combined with pectin, carrageenan, chitosan and psyllium

Alginate-based blends consisting of carrageenan, pectin, chitosan or psyllium husk powder were prepared for assessment of the best formulation aimed at encapsulation of caffeine. Alginate-pectin blend exhibited the lowest viscosity and provided the smallest beads. Alginate-psyllium husk blend was characterised with higher viscosity, yielding the largest bead size and the highest caffeine encapsulation efficiency (83.6%). The release kinetics of caffeine indicated that the porosity of alginate hydrogel was not reduced sufficiently to retard the diffusion of caffeine from the beads. Chitosan coated alginate beads provided the most retarded release of caffeine in water. Morphological characteristics of beads encapsulating caffeine were adversely affected by freeze drying. Bitterness intensity of caffeine-containing beads in water was the lowest for alginate-psyllium beads and chitosan coated alginate beads. Higher sodium alginate concentration (3%) for production of hydrogel beads in combination with psyllium or chitosan coating would present the most favourable carrier systems for immobilization of caffeine.

Physical, bioactive and sensory quality parameters of reduced sugar chocolates formulated with natural sweeteners as sucrose alternatives

In this study, sugar alcohols, dietary fibers, syrups and natural sweeteners were used as sucrose alternatives in the production of reduced sugar chocolates (50% of cocoa parts) with enhanced bioactive profile. Formulated chocolates were evaluated for their physical (particle size distribution, texture) and sensory properties, sugar composition, polyphenolic compounds content and antioxidant capacity. All produced reduced sugar chocolates ensured >20% lower calorific value than conventional chocolate (prepared with sucrose). Formulated chocolates containing stevia leaves and peppermint exhibited the best sensory properties (especially with regard to mouthfeel, sweetness and herbal aroma), as well as the highest polyphenolic content and antioxidant capacity. Particle size and hardness of chocolates increased in comparison to conventional chocolate, in particular when the combination of fructose and isomalt or lactitol was used. The bioactive profile of produced chocolates was enriched with phenolic acids, flavone (luteolin and apigenin) and flavonol (quercetin) derivatives, which were not identified in control chocolate.

Reducing Fat Globules Particle-Size in Goat Milk : Ultrasound and High Hydrostatic Pressures Approach

Innovative and eco-friendly food technologies in practical usage today like Ultrasound (US) and High Hydrostatic Pressures (HHP) are feasible to adequately maintain various food properties while processed, such as texture, sensorial and organoleptic characteristics, and microbiological issues as well. Benchmarked attribute of the mentioned approach lies in the ability of US and HHP to control and withhold both temperature and treatment duration. While temperature could be controlled within room ambient, treatment time is mostly below 30 minutes. US and HHP treatment were performed as separate treatments in order to obtain better homogenization. Goat milk was exposed to ultrasonic propagation up to 100 W of nominal power and high pressures up to 600 MPa. Maximum treatment time was 9 minutes. Ultrasonic homogenization indicates enhanced homogeneity of fat globules while high pressure process parameters have a significant influence on the observed mean particle diameter (fat globules). Improved stability and quality of emulsions (goat milk) was obtained by both applied processes. Statistical analysis indicated the influence of process parameters on fat globule size distribution between 0.3 – 4 µm and variance lower than 0.6.

Assessment of Drying Characteristics and Texture in Relation with Micromorphological Traits of Carob Pods and Seeds (Ceratonia silliqua L.)

Carob tree (Ceratonia siliqua L.) is a perennial leguminous evergreen tree native to the coastal regions of the Mediterranean basin and is considered to be an important component of vegetation for economic and environmental reasons. Two constituents of the pod, pulp and seeds, can be used as feed or in food production. In this study, drying characteristics, texture and microstructure of carob pods were studied. Three different carob samples were prepared: whole carob pod, carob pod parts and carob seed. The drying experiments and the modelling showed that carob seeds had the highest drying rate, followed by pod parts and the whole, intact carob fruit. Texture studies showed that the maximum compression force depended on the area of the carob fruit on which compression tests were performed. The seeds showed the highest compression force, followed by the stem zone, the tip and the centre of the fruit. Differences in drying behaviour and texture of carob pods can successfully be interpreted by the micromorphology of the carob pods and seeds. Determining the drying rate, maximum compressive force and micromorphological traits is of great importance for further carob processing (e.g. milling, sieving, carob bean gum production or usage in food or feed products).

Application of whey protein isolates and zein for the formulation of alginate-based delivery systems encapsulating Ganoderma lucidum polyphenols

Due to the rich phytochemical composition of the medicinal mushroom Ganoderma lucidum, especially its ß-glucan-based polysaccharides and triterpenes, but polyphenols, amino acids, and proteins as well, Ganoderma is often used in various nutraceutical and functional food products. Lately these products have been formulated with microencapsulated forms of active compounds in order to prevent their degradation after oral consumption and under processing conditions. The aim of this study was to characterize and encapsulate polyphenols from the aqueous extract of Ganoderma, using ionic gelation of alginate (A) and its combination with whey protein isolates (WPI) and zein (Z). The obtained hydrogel beads were scanned for physico-chemical and morphological properties, encapsulation efficiency of polyphenols, and their release kinetics in simulated gastrointestinal fluids. The addition of WPI to the alginate resulted in the reduction of the particle size and the spherical shape of the beads, while beads formulated with zein were characterized as larger, with irregular morphology. Encapsulation efficiency of total polyphenols has been determined as follows: 76.91% (A-WPI) < 83.91% (A) < 85.42% (A-Z). The most extended release of polyphenols in simulated gastrointestinal fluids has been achieved by employing WPI in the alginate delivery system. The implementation of additional coatings resulted in the enhanced properties of plain alginate carrier, where alginate-based hydrogels immobilizing Ganoderma polyphenols proved to be potential functional ingredients.

Biomechanical Comparison of the Temporalis Muscle Fascia, the Fascia Lata, and the Dura Mater

Abstract The purpose of our research is to prove that elastic biomechanical characteristics of the temporalis muscle fascia are comparable to those of the fascia lata, which makes the temporalis muscle fascia adequate material for dural reconstruction in the region of the anterior cranial fossa. Fifteen fresh human cadavers, with age range from 33 to 83 years (median age: 64 years; mean age: 64.28 years), were included in the biomechanical study. Biomechanical stretching test with the comparison of elasticity among the tissues of the temporalis muscle fascia, the fascia lata, and the dura was performed. The samples were stretched up to the value of 6% of the total sample length and subsequently were further stretched to the maximum value of force. The value of extension at its elastic limit for the each sample was extrapolated from the force‐extension curve and was 6.3% of the total sample length for the fascia lata (stress value of 14.61 MPa), 7.4% for the dura (stress value of 6.91 MPa), and 8% for the temporalis muscle fascia (stress value of 2.09 MPa). The dura and temporalis muscle fascia shared the same biomechanical behavior pattern up to the value of their elastic limit, just opposite to that of the fascia lata, which proved to be the stiffest among the three investigated tissues. There was a statistically significant difference in the extension of the samples at the value of the elastic limit for the fascia lata in comparison to the temporalis muscle fascia and the dura (p = 0.002; Kruskal‐Wallis test). Beyond the value of elastic limit, the temporalis muscle fascia proved to be by far the most elastic tissue in comparison to the fascia lata and the dura. The value of extension at its maximum value of force for the each sample was extrapolated from the force‐extension curve and was 9.9% of the samples total length for the dura (stress value of 10.02 MPa), 11.2% for the fascia lata (stress value of 23.03 MPa), and 18.5% (stress value of 3.88 MPa) for the temporalis muscle fascia. There was a statistically significant difference in stress values at the maximum value of force between the dura and the temporalis muscle fascia (p = 0.001; Mann‐Whitney U test) and between the dura and the fascia lata (p < 0.001; Mann‐Whitney U test). Because of its elasticity and similarity in its mechanical behavior to the dura, the temporalis muscle fascia can be considered the most suitable tissue for dural reconstruction.

Oral antiseptics and nickel–titanium alloys: mechanical and chemical effects of interaction

The effect of oral antiseptics on the corrosion of nickel–titanium (NiTi) alloys with various coating was investigated. Uncoated, titanium nitride-coated and rhodium-coated NiTi archwires (0.020 × 0.020″) were tested in interaction with artificial saliva pH 4.8 and oral antiseptics based on hyaluronic acid (Gengigel), chlorhexidine (Curasept) and essential oils in alcohol base (Listerine). The dynamics of nickel and titanium ions release were recorded during 28 days. Springback ratio and modulus of resilience were assessed by three-point bending test. The results showed that corrosion of NiTi is related to type of antiseptic mouth rinse and coating formulations. Exposure to an artificial saliva and antiseptics tend to reduce flexibility and resilience of NiTi archwires. The influence of the media is more significant than the influence of the type of the alloys coating. The largest release of nickel ions is in the first 3 days. Antiseptics do not cause further deterioration of the elastic properties in uncoated NiTi compared to saliva. As a result of exposure of nitrified NiTi wires in Listerine, there is bigger release of nickel ions, decrease in elastic properties and lower force delivery in unload. Listerine tends to reduce elastic properties of rhodium-coated wires also. In conclusion, except for Listerine, changes of mechanical characteristics induced by antiseptics are small and would not have a clinically important impact. Generally, Curasept would be the most suitable option.

Structuring new alginate network aimed for delivery of dandelion (Taraxacum officinale L.) polyphenols using ionic gelation and new filler materials

Alginate hydrogels are often used for immobilization of plant-derived bioactive compounds by fast and simple ionic gelation technique. However, the structure of alginate gel network is very porous and mostly result with high-diffusion rates of encapsulated compound, what limits its application as delivery vehicle. In order to prevent losses of bioactives and prepare efficient encapsulation systems, the aim of this study was to evaluate a potential of new natural fillers, cocoa powder (CP) and carob (C) for structuring alginate network aimed for encapsulation of aqueous dandelion (Taraxacum officinale L.) leaf extract using ionic gelation. Whey protein isolates served as a standard filler. The influence of different concentrations of gelling medium (2% and 3% calcium chloride) on encapsulation properties of alginate systems was also evaluated. Calcium concentration affected morphological properties (more acceptable when using 3% CaCl2), while textural properties and encapsulation efficiency of polyphenols and retained antioxidant capacity were more influenced by selected delivery materials. Alginate-whey protein isolates beads were scored with the highest loading capacity of polyphenols (>93%), while newly formulated binary mixtures (alginate-cocoa powder and alginate-carob) also enabled highly efficient entrapment of polyphenols (>88%). The slowest release of polyphenols in simulated gastrointestinal fluids were obtained when alginate was combined with CP and C, where system alginate-cocoa powder prepared with lower concentration of calcium chloride (2% CaCl2) enabled the most extended release of total polyphenols and hydroxycinnamic acids. Obtained results strongly justified implementation of new plant-derived functional fillers (cocoa powder and carob) for encapsulation purposes and opened new directions for designing of binary carriers.

Antioxidant activity of high-pressure processed tangerine juice

High-pressure processing is technology that has the potential to ensure microbiological safety of low pH fruit juices, while retaining freshness, increasing the stability of juice and retaining of all bioactive compounds. Investigation of HHP parameters on antioxidant activity of bioactive compounds from tangerine juice was conducted. Processing time and pressure parameters were chosen to ensure log5 inactivation of microorganisms. Pressures were 0 (fresh juice), 400, 500 and 600 MPa during 5 and 10 min. Antioxidant capacity (DPPH) and FRAP were measured and statistically analyzed using ANOVA and posthoc tests. Obtained results show that processing at lowest pressure leads to 13, 28 % decrease in antioxidant activity, compared to fresh juices. FRAP values slightly increase at 500 MPa (for 7, 29 %), as well as TOAC. The increase in pressure over 500 MPa did not lead to further changes in FRAP and TOAC values. Processing time had a positive influence, as there is an increase in both measured properties. Pressures over 400 MPa are excessive from an economic standpoint, and not necessary to achieve microbiological safety and juice stability, however, there is evidence that HHP influence on the cellular matrix, which results in the increased diffusion from the cells, which increases the antioxidant activity.

Assessment of Drying Characteristics and Texture in Relation with Micromorphological Traits of Carob (Ceratonia silliqua L.) Pods and Seeds.

Carob tree (Ceratonia siliqua L.) is a perennial leguminous evergreen tree native to the coastal regions of the Mediterranean basin and is considered to be an important component of vegetation for economic and environmental reasons. Two constituents of the pod, pulp and seeds, can be used as feed or in food production. In this study, drying characteristics, texture and microstructure of carob pods were studied. Three different carob samples were prepared: whole carob pod, carob pod parts and carob seed. The drying experiments and the modelling showed that carob seeds had the highest drying rate, followed by pod parts and the whole, intact carob fruit. Texture studies showed that the maximum compression force depended on the area of the carob fruit on which compression tests were performed. The seeds showed the highest compression force, followed by the stem zone, the tip and the centre of the fruit. Differences in drying behaviour and texture of carob pods can successfully be interpreted by the micromorphology of the carob pods and seeds. Determining the drying rate, maximum compressive force and micromorphological traits is of great importance for further carob processing (e.g. milling, sieving, carob bean gum production or usage in food or feed products).