Spontaneous microencapsulation of geraniol by zein

Abstract

Geraniol was successfully micro-encapsulated with zein in a one-step phase separation process in which the zein and geraniol were both initially dissolved in a water-ethanol mixture. Microcapsules were only formed at geraniol-to-zein mass ratios above unity. This is ascribed to the relative solubility of the oil and protein in the solvent at the point of incipient phase separation: The geraniol must phase separate first before zein precipitation commences. The resultant oil droplets subsequently provide the interfacial surfaces that act as nucleation sites for the precipitation of the amphoteric zein molecules on continued dilution with water. The near spherical microcapsules formed under these conditions, comprised a foamed closed-cell wall that enclose large internal cavities in which the geraniol was trapped. The highest particle yield, 85.3%, and oil encapsulation efficiency, 83.5%, were obtained at a geraniol to zein mass ratio of 3:1. The particle size distribution for this system was log-normal with d 10 , d 50 and d 90 values of 10, 32 and 88 μm respectively. The temperature dependent geraniol release rate from these capsules followed power law kinetics with a release exponent of 0.80.

Preparation, Characterization, Release and Antibacterial Properties of Cinnamon Essential Oil Microcapsules

“…This particle size is similar to that measured for many essential oil microcapsules [13,45,46]. The image was normally distributed and relatively narrow, clarifying that the microcapsules prepared under optimal process conditions were of uniform size, which was consistent with the results in the literature [47].…”

“…This particle size is similar to that measured for many essential oil microcapsules [13,45,46]. The image was normally distributed and relatively narrow, clarifying that the microcapsules prepared under optimal process conditions were of uniform size, which was consistent with the results in the literature [47]. The significantly larger particle size compared to the freeze-dried dry capsule is mainly because the wall materials prepared from the microcapsules were hydrophilic polymers with strong swelling properties [48], which also indicated that they can be easily redispersed into the aqueous media.…”

Perfume Encapsulation via Vapor Induced Phase Separation

“…Once the correct temperature range is identified, it is possible to estimate the mass of the encapsulated active (active in capsules) as the weight loss of the capsules in that temperature range. The encapsulation efficiency (EE) can be defined as the mass of encapsulated active material compared to the mass of the active material added to the initial formulation [23], as reported in Equation (1) below: EE = active in capsules total active…”