Aroma encapsulation in carnauba wax, alginate and polyvinyl alcohol

Abstract

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...

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...