Alpha‐tocopherol microspheres with cross‐linked and acetylated inulin and their release profile in a hydrophilic model

Abstract

Artículo de publicación ISI.Alpha-tocopherol (AT) was encapsulated with native (NIn), acetylated (AIn) or cross-linked (CIn) inulin (two degrees each) by spray-drying. A face central composite experimental design for each system (AT-NIn, AT-AIn(1), AT-AIn(2), AT-CIn1, and AT-CIn2) was evaluated to determine the influence of inlet air temperature and AT/coating material ratio on the AT encapsulation percentage (EP). The AT microspheres obtained under optimal conditions were characterized determining the AT EP, morphology and their release profile in a hydrophilic system. The AT encapsulating percentage reached values above 86% in all the systems studied. The acetylation and cross-linking of inulin improved slight but significantly the AT encapsulating percentage respect to native inulin. The release profiles showed biphasic behavior, being the first and second zone attributed to uncovered and encapsulated AT, respectively. The AT release was <15% (0-540min) from all AT-inulin microparticles, corresponding mainly to superficial AT release, following Higuchi model consistent with a diffusional mechanism. AT release rate constant from AT-NIn microspheres was significantly lower than those of AT-AIn and AT-CIn. The AT release pattern suggest that the microparticles could be applied in the design of functional foods, preserving the nutritional role of AT.Grant No. 1090209 from The National Fund for Scientific and Technological Development (Fondecyt, Chile)

Release Kinetic in Yogurt from Gallic Acid Microparticles with Chemically Modified Inulin

“…In general, the GA was released quickly from microparticles (<2 h). As seen in the release profile graph (Fig ), GA‐AIn and GA‐NIn systems studied showed a biphasic behaviour as was previously reported (Poulain and others ; Robert and others ; García and others ; Palma and others ). The first zone was attributed to a release of the nonencapsulated GA (superficial GA) on the surface of the microparticles.…”

“…Optimisation of gallic acid microencapsulation with native inulin (GA‐NIn) and acetylated inulin (GA‐AIn), was previously reported by our group (Robert and others ). In this study, we used the same independent variables but different experimental design.…”

“…The modification of cross‐linked inulin was confirmed by 31 P‐NMR and FT‐IR (both spectra in supplementary material) as shown in Table S1. The phosphorus level was determined by atomic emission spectroscopy (ICP‐AES), obtaining a cross‐linking degree (CD) value of 0.052, which was obtained from the relationship between moles of phosphorus incorporated into the native inulin and the total moles of native inulin (García and others ).…”

“…Of these polymers, maltodextrin is the most common biopolymer used as an encapsulating agent by spray‐drying because of its high solubility in water. When the polyphenols encapsulated with a soluble biopolymer are added to yogurt, they are quickly released and become exposed to the food matrix, losing their bioactive properties (de Vos and others ; Robert and others ; García and others ).…”

“…Cross‐linked inulin (CIn) was synthesized by a reaction with phosphoryl chloride, according to the method described by García and others (). Native inulin (100 g) was dispersed in water (400 mL) with constant stirring for 1 h at 25 °C and then sodium sulfate was added followed by the addition of NaOH (1 M) until reached pH 11.…”