Aroma encapsulation in carnauba wax, alginate and polyvinyl alcohol

U ovoj disertaciji je ispitivana inkapsulacija prehrambenih aroma uz primenu različitih metoda inkapsulacije i u kombinaciji sa prirodnim i sintetičkim nosačima. Cilj istraživanja je bio dobijanje inkapsulata kako tečnih tako i čvrstih aroma koje se najčešće koriste u prehrambenoj industriji. Ispitivana su tri nosača za inkapsulaciju aroma: karnauba vosak, alginat i polivinil alkohol. Kao model arome su korišćene: etil vanilin, komercijalno dostupna aroma kokosa i D-limonen. Karnauba vosak je korišćen kao nosač za inkapsulaciju etil vanilina, pri čemu su dobijene sferne čestice čiji je prečnik uglavnom bio ispod 250μm. Čestice na bazi karnauba voska sa etil vanilinom su dobijene primenom disperzione (emulzifikacione) metode i disperzione tehnike (disperzija komprimovanim vazduhom). Metodom disperzije vazduhom su dobijene čestice pravilnijeg sfernog oblika sa većom inkapsulacionom efikasnošću. Takođe, termička svojstva inkapsulisanog etil vanilina su poboljšana u poređenju sa slobodnom aromom. Termičko otpuštanje inkapsulisanog etil vanilina se odigravalo na višim temperaturama (do~270°C) u poređenju sa slobonom aromom (do ~220°C). Ca-alginatne čestice sa tečnim i čvrstim aromama su dobijane metodom elektrostatičke ekstruzije. Inkapsulacijom etil vanilina u Ca-alginatni matriks su ostvarena bolja termička svojstva inkapsulisane arome uz postizanje kontrolisanog termičkog otpuštanja arome u širem temperaturnom opsegu u odnosu na slobodnu aromu. Aroma kokosa i D-limonen su inkapsulisani u Ca-alginatne čestice primenom iste procedure kao i u slučaju inkapsulacije etil vanilina. Alginat je pokazao dobra emulgujuća svojstva, što je osnovni uslov za postizanje visoke inkapsulacione efikasnosti. Rezultati termičke analize su pokazali da obe arome u inkapsulisanom obliku imaju bolja termička svojstva u odnosu na slobodne arome. Rehidracija je korišćena za ispitivanje adsorpcije vode u inkapsulate uz razvoj novog modela rehidracije. Polivinil alkohol je u kombinaciji sa alginatom korišćen za dobijanje čestica sa inkapsulisanim etil vanilinom metodom elektrostatičke ekstruzije. Primenom viših napona kod metode elektrostatičke ekstruzije-elektrospininga dobijeni su filmovi na bazi polivinil alkohola koji se sastoje od nanovlakana. Filmovi na bazi polivinil alkohola su pokazali dobra hemijska, mehanička, termička i antimikrobna svojstva...In this study, the encapsulation of food flavours by different methods combined with natural and synthetic carriers was investigated. The goal of this study was production of encapsulated forms of both, liquid and solid flavours that are commonly used in food industry. Three different carrier materials for flavour encapsulation were tested: carnauba wax, alginate and polyvinyl alcohol. Ethyl vanillin, comercial coconut flavor and D-limonen were used as model flavors. Carnauba wax was used as carrier for encapsulatio of ethyl vanillin in the form of spherical particles with size mainly below 250μm. Carnauba particles loading ethyl vanillin was produced by using dispersion (emulzification) method and spray congealing method (dispersion with compressed air). Particles with more regular shperical shape and higher encpasulation efficiency were probuced by using spray congealing method. Also, thermal stability of encapsulated ethyl vanillin was improved compared to free flavour. Thermal release of encapsulated ethyl vanillin occured at higher temperature (up to ~270°C) compared to free flavour (up to ~220°C). Ca-alginate beads loading liquid and solid flavours were produced by electrostatic extrusion. By encapsulation of ethyl vanillin into Ca-alginate matrix better thermal properties of encpasulated flavour were achieved with controled release in the broader temperature range compared to free flavor. Coconut flavor and D-limonene (liquid flavours) were encapsulated into Ca-alginate beads using same procedure as in the case of ethyl vanillin. Alginate showed good properties for production of stable flavours emulsion, which is critical for high encapsulation efficiency. The results of thermal stability showed that both flavours in encapsulated forms have better thermal stability compared to free flavors. Rehydration studies were used to test the water adsorption properties of encapsulates and new model of rehydration was developed. Polyvinyl alcohol was used combined with alginate for production of particles loaded with ethyl vanillin by electrostatic extrusion. At higher voltage using electrostatic-electrospinning technique polyvinyl alcohol films with ethyl vanillin consisted of nanofibers were produced. Polyvinyl alcohol films loading ethyl vanillin showed good chemical, mechanical, thermal and antimicrobial properties..

Polymer characteristics and mechanical properties of bulk-fill, giomer, fiber-reinforced and low-shrinkage composites

Introduction/Objective. The objective was to determine the degree of conversion (DC), cross-link density, percentage of leachable monomers, flexural strength (FS), and hardness (HV) of nanohybrid, nanofilled bulk-fill, giomer, fiber-reinforced, and low-shrinkage composites. Methods. Standardized specimens (n = 5/group) of Tetric EvoCeram Bulk Fill, Filtek Bulk Fill, Beautifil, EverX posterior, Kalore, Filtek Z250 (microhybrid control), and Tetric EvoCeram (nanohybrid control) were subjected to micro-Raman spectroscopy, three-point bending, and HV. Cross-linking density and leachable monomers were ascertained based on the ratio of HV and DC before and after immersion in absolute ethanol. Results. DC was in the range 50.4–70.5%, the highest for Filtek Bulk and the lowest for Kalore. The highest %DC change was in Beautifil (10.3%) and the lowest in Filtek Bulk (1.4%) and Z250 (1.28%). FS ranged between 78.9 MPa (TEC) and 126.7 MPa (Filtek Bulk). HV ranged between 58.6 (Kalore) and 113.9 (Z250) and significantly decreased post-immersion (19–55%). HV48h inversely correlated to HV% loss (r = -0.761), whilst DC positively correlated with FS (r = 0.893). Conclusion. Filtek Bulk, EverX, and Z250 showed the highest DC. The lowest DC and mechanical properties were observed for Kalore. The greatest cross-link density was shown by Filtek Bulk. There were up to 10% of leachable monomers. DC and FS positively correlated

Novel amino modified GMA-EGDMA-m-PMMA monolith for efficient cationic pollutant removal

Novel macro/micro-porous monolith material containing surface amino functional groups was developed for efficient cationic pollutant removal. The monolith was prepared by copolymerization process of monomers glycidyl methacrylate (GMA), ethylene glycol dimethacrylate (EGDMA) and modified low molar mass poly(methyl methacrylate) (PMMA). In order to improve mechanical stability of GMA-EGDMA monolith, surface of PMMA was modified with ethanol amine in first step, and introduction of methacryloyl chloride in a second step produced m-PMMA. Synthesized GMA-EGDMA-m-PMMA monolith was modified with poly(ethylene imine) (PEI). The effectiveness of copolymerization, as well as introduction of amino groups via PEI modification were confirmed by FTIR and Raman analyses. The morphological appearance of the synthesized monolith, examined by scanning electron microscopy (SEM), clearly indicates porous structure. The results of textural parameters, i.e. monolith porosity, determined by using liquid saturating method, indicate high degree of porosity. Cationic pollutant removal capacity, cadmium and lead, of 32.0 and 42.5 mg g−1 at 25 °C indicates that this monolith is high efficient. This macro/micro-porous monolith could be a promising adsorbent because of its low-cost synthesis process and excellent performance

An overview of encapsulation technologies for food applications

Encapsulation is a process to entrap active agents within a carrier material and it is a useful tool to improve delivery of bioactive molecules and living cells into foods. Materials used for design of protective shell of encapsulates must be food-grade, biodegradable and able to form a barrier between the internal phase and its surroundings. Among all materials, the most widely used for encapsulation in food applications are polysaccharides. Proteins and lipids are also appropriate for encapsulation. Spray drying is the most extensively applied encapsulation technique in the food industry because it is flexible, continuous, but more important an economical operation. Most of encapsulates are spray-dried ones, rest of them are prepared by spray-chilling, freeze-drying, melt extrusion and melt injection. Molecular inclusion in cyclodextrins and liposomal vesicles are more expensive technologies, and therefore, less exploited. There are number of reasons why to employ an encapsulation technology and this paper reviews some of them. For example, this technology may provide barriers between sensitive bioactive materials and the environment, and thus, to allow taste and aroma differentiation, mask bad tasting or smelling, stabilize food ingredients or increase their bioavailability. One of the most important reasons for encapsulation of active ingredients is to provide improved stability in final products and during processing. Another benefit of encapsulation is less evaporation and degradation of volatile actives, such as aroma. Furthermore, encapsulation is used to mask unpleasant feelings during eating, such as bitter taste and astringency of polyphenols. Also, another goal of employing encapsulation is to prevent reaction with other components in food products such as oxygen or water. In addition to the above, encapsulation may be used to immobilize cells or enzymes in food processing applications, such as fermentation process and metabolite production processes. There is an increasing demand to find suitable solutions that provide high productivity and, at the same time, satisfy an adequate quality of the final food products. This paper aims to provide a short overview of commonly used processes to encapsulate food actives

Inkapsulacija bioaktivnih jedinjenja sporednih proizvoda prerade voća

An increased environmental awareness has led to new trends in food industry, which are reflected in intensive studies on exploitation of fruit processing byproducts. Additionally, consumers' tendency to a healthy lifestyle has initiated the development of diverse functional food products. High amounts of by-products, such as peels, seeds, and stones, are discarded during fruit processing. It represents a problem both from the environmental and the economic point of view. On the other hand, the resulting residues are potential sources of numerous bioactive compounds. Therefore, fruit processing by-products such as substrates for the extraction of phenolic compounds, natural pigments, dietary fibers, protein isolates and oils attract great interest. These extracts have a great potential for the development of dietary supplements and new functional food products with beneficial health effects. However, bioactive compounds are susceptible to degradation, which represents a critical factor for their successful incorporation into food products. In this regard, the main challenge is to ensure the stability of bioactive compounds during processing, storage and in the gastrointestinal tract, i.e. to preserve their bioactivity and bioavailability. This challenge could be accomplished by the use of encapsulation. Namely, the formation of a physical barrier between an active compound and its surrounding is an effective way of protection. The present paper indicates the potential of by-products originating from the processing of apples, grapes, plums, raspberries and sour cherries as sources of bioactive compounds. It also points out the benefits that could be achieved by the encapsulation of bioactive compounds extracted from fruit processing by-products in order to develop new functional food products.Svest o očuvanju životne sredine dovela je do novih trendova u prehrambenoj industriji, koji se između ostalog ogledaju i u intenzivnom izučavanju potencijala iskorišćenja otpada nastalog pri proizvodnji hrane. Pored toga, težnja ka zdravom načinu života doprinela je razvoju funkcionalnih prehrambenih proizvoda. Tokom prerade voća mnogi delovi ploda, kao što su pokožica, semenke i koštice, zaostaju, što predstavlja problem sa ekološkog i ekonomskog aspekta. S druge strane, ovi ostaci predstavljaju potencijalne izvore bioaktivnih jedinjenja. U tom pogledu, nastali sporedni proizvodi prerade voća se intenzivno izučavaju kao sirovine za ekstrakciju fenolnih jedinjenja, prirodnih pigmenata, dijetetskih vlakana, proteinskih izolata i ulja, kao i za proizvodnju suplemenata sa potencijalnim zdravstvenim benefitima. Ipak, kritičan faktor uspešne implementacije ekstrakata bogatih bioaktivnim jedinjenjima u prehrambene proizvode jeste njihova podložnost degradaciji. Prema tome, kao glavni izazov nameće se postizanje stabilnosti bioaktivnih jedinjenja tokom prerade i skladištenja, odnosno očuvanje njihove bioaktivnosti i biodostupnosti. Odgovor na postavljeni izazov očuvanja bioaktivnosti sastojaka hrane može da ponudi inkapsulacija. Naime, inkapsulacija se bazira na formiranju fizičke barijere između bioaktivnih jedinjenja i različitih neželjenih faktora sredine, kao što su visoka temperatura, svetlost, itd. U ovom radu ukazano je na potencijal sporednih proizvoda prerade jabuka, grožđa, šljiva, malina i višanja kao izvora bioaktivnih jedinjenja. Takođe, prikazane su prednosti koje se postižu inkapsulacijom bioaktivnih jedinjenja ekstrahovanih iz sporednih proizvoda prerade voća u cilju razvoja novih, funkcionalnih proizvoda

Mineralized agar-based nanocomposite films: Potential food packaging materials with antimicrobial properties

New mineralized, agar-based nanocomposite films (Zn-carbonate and Zn-phosphate/agar) were produced by a combination of in situ precipitation and a casting method. The presence of minerals significantly influenced the morphology, properties and functionality of the obtained nanocomposites. Reinforcement with the Zn-mineral phase improved the mechanical properties of the carbonate-mineralized films, but had a negligible effect on the phosphate-mineralized samples. Both nanocomposites showed improved optical and thermal properties, better Zn(II) release potential in a slightly acidic environment and exhibited antimicrobial activity against S. aureus. These results suggest that Zn-mineralized agar nanocomposite films could be potentially used as affordable, eco-friendly and active food packaging materials.This is the peer reviewed version of the paper: Malagurski, I., Levic, S., Nesic, A., Mitric, M., Pavlovic, V., & Dimitrijevic-Brankovic, S. (2017). Mineralized agar-based nanocomposite films: Potential food packaging materials with antimicrobial properties. Carbohydrate Polymers, 175, 55–62. [https://doi.org/10.1016/j.carbpol.2017.07.064][https://www.sciencedirect.com/science/article/abs/pii/S0144861717308408?via%3Dihub

Atypical antipsychotic clozapine binds fibrinogen and affects fibrin formation

Clozapine is an atypical antipsychotic used for the treatment of schizophrenia. The prescribed target daily doses may reach 900 mg. Literature studies report a connection between clozapine usage and thrombosis development. Our in vitro study aimed to provide insight into molecular bases of this observation, investigating clozapine binding to fibrinogen, the main plasma protein involved in hemostasis. Fibrinogen/clozapine interaction was confirmed by protein fluorescence quenching, with an affinity constant of 1.7 × 105 M−1. Direct interactions did not affect the structure of fibrinogen, nor fibrinogen melting temperature. Clozapine binding affected fibrin formation by reducing coagulation speed and thickness of fibrin fibers suggesting that in the presence of clozapine, fibrinogen may acquire thrombogenic characteristics. Although no difference in fibrin gel porosity was detected, other factors present in the blood may act synergistically with altered fibrin formation to modify fibrin clot, thus increasing the risk for development of thrombosis in patients on clozapine treatment. ORAC and HORAC assays showed that clozapine reduced free radical-induced oxidation of fibrinogen. All observed effects of clozapine on fibrinogen are dose-dependent, with the effect on fibrin formation being more pronounced.This is the peer-reviewed version of the article: Gligorijević, N.; Vasović, T.; Lević, S. M.; Miljević, Č.; Nedić, O.; Nikolić, M. Atypical Antipsychotic Clozapine Binds Fibrinogen and Affects Fibrin Formation. International Journal of Biological Macromolecules 2020, 154, 142–149. [https://doi.org/10.1016/j.ijbiomac.2020.03.119

Synthesis and antimicrobial properties of Zn-mineralized alginate nanocomposites

New bioactive and antimicrobial biomaterials were produced by alginate-mediated biomineralization with Zn-mineral phase. The synthesis procedure is simple, cost-effective and resulted in. two different Zn-mineralized alginate nanocomposites, Zn-carbonate/Zn-alginate and Zn-phosphate/Zn-alginate. The presence of Zn-mineral phase and its type, have significantly affected nanocomposite morphology, stability, total metallic loading and potential to release Zn(II) in physiological environment. Antimicrobial experiments showed that both types of Zn-mineralized nanocomposites exhibit strong antimicrobial effect against Escherichia coli, Staphylococcus aureus and Candida albicans. These results suggest that alginate biomineralization, where minerals are salts of essential metallic ions like Zn(II), represents a'good strategy for designing multifunctional biomaterials for potential biomedical applications.This is the peer reviewed version of the paper: Malagurski, I., Levic, S., Pantic, M., Matijasevic, D., Mitric, M., Pavlovic, V., & Dimitrijevic-Brankovic, S. (2017). Synthesis and antimicrobial properties of Zn-mineralized alginate nanocomposites. Carbohydrate Polymers, 165, 313–321. [https://doi.org/10.1016/j.carbpol.2017.02.064

Savremeni procesi inkapsulacije u tehnologiji hrane

The encapsulation processes have been intensively studied in the recent years as possible alternative to conventional food technologies. Encapsulation of food active compounds is based on formation of protective layer(s) around active compound using adequate encapsulation technique. The role of protective layer is to prevent degradation of active compound and to provide controlled release of protected ingredient under defined conditions. Modern food technology offers numerous solutions for encapsulation of food ingredients, plant extracts, microorganism cells, etc. Also, there are numerous available carrier materials that could be used for specific demand. Encapsulation is complex process and application of encapsulation techniques in the food production requires knowledge from different areas of science. The aim of this review is to summarize different encapsulation processes that are already applied in food technology as well as those that are under development. This paper analyses current experience in the area of encapsulation for food industry. Several encapsulation procedures such as spray drying, fluid bed coating, encapsulation in polymer particles, coacervation and encapsulation in cyclodextrins were analyzed.Procesi inkapsulacije su intenzivno izučavani poslednjih godina kao moguća alternativa konvencionalnim tehnologijama u proizvodnji hrane. Inkapsulacija aktivnih komponenti hrane se bazira na formiranju omotača (ili više slojeva omotača) oko aktivne komponente korišćenjem odgovarajuće metode inkapsulacije. Uloga zaštitnog omotača je, s jedne strane da spreči degradaciju aktivne komponente, a sa druge strane da omogući kontrolisano otpuštanje zaštićenih komponenti pod određenim uslovima. Moderna proizvodnja hrane nudi brojna rešenja za inkapsulaciju komponenti hrane, biljnih ekstrakata, ćelija mikroorganizama, itd. Takođe, postoji veliki broj dostupnih materijala nosača koji mogu da zadovolje specifične zahteve. Inkapsulacija je složen proces i primena inkapsulacionih tehnika u proizvodnji hrane zahteva znanje iz različitih oblasti nauke. Cilj ovog rada je da objedini različita iskustva iz inkapsulacionih procesa koji se već koriste u prehrambenoj tehnologiji, kao i onih procesa koji su još u fazi razvoja. Ovaj rad daje analizu i dosadašnja iskustva u oblasti inkapsulacije za potrebe industrije hrane. Data je analiza nekoliko inkapsulacionih procedura kao što su sprej sušenje, oblaganje u fluidizovanom sloju, inkapsulacija u polimernim česticama, koacervacija i inkapsulacija u ciklodekstrine

HPLC analysis of ascorbic acid in pretreated and dried red pepper (Capsicum annum)

Red pepper (Capsicum annum) fruits contain high amount of ascorbic acid (vitamin C), which is of great importance for human health. The aim of this study was to found how various pretreatments and drying methods influence on retention of ascorbic acid in dried pepper. The cultivar “Horgoška sweet 6”, often used for the production of paprika, was selected for analysis. Five sets of experiments were performed to investigate the effect of the following parameters: pretreatment temperature (20 oC, 50 oC, 80 oC), pH value (3, 6.5, 10), additive (0.25% citric acid, 0.25 % potassium metabisulfite and 0.25 % citric acid + 0.25 % potassium metabisulfite), ultrasound (off and on) and drying method (hot air drying and freeze drying). The initial content of ascorbic acid in fresh pepper was 292 mg/100 g dry basis (d.b.) and it was reduced after all pretreatment and after drying of pretreated samples. Most of examined pre-drying treatments improve retention of ascorbic acid in final dried peppers, except treatments at 80 oC. Our results indicate that temperature and drying method were parameters that significantly influenced ascorbic acid content in dried peppers. Other parameters were not significant, but had a certain effect on retention of ascorbic acid. The best parameters were temperature 20 oC, pH 6.5, citric acid/potassium metabisulfite, without applying ultrasound including freeze drying method