Kinetic analysis of aroma compound release from Citrus aurantium essential oil-casein-phospholipid-nanocomposites

Abstract

In this study, Citrus aurantium essential oil encapsulated in casein-phospholipid nanocomposites (CAEO–CS–PL-NCs) was prepared and evaluated for controlled-release capacity of aroma compounds. The particle size of the nanocomposites was strongly influenced by the phospholipid concentration in the nanocomposites. The Avrami and Korsmeyer-Peppas kinetic models were used to analyze the aroma release kinetics of freeze-dried CAEO–CS–PL-NCs (FD-CAEO–CS–PL-NCs) at different temperatures and relative humidities. FD-CAEO–CS–PL-NCs were stored for various times with tea leaves to evaluate their potential for making scented teas. The Avrami kinetic analysis indicated that the release of aroma compounds from FD-CAEO–CS–PL-NCs conformed to diffusion-limited, or first-order kinetics, depending on the temperature and relative humidity. The Korsmeyer-Peppas kinetic analysis indicated that the release of aroma compounds from FD-CAEO–CS–PL-NCs involved three release mechanisms, Fickian diffusion, non-Fickian diffusion and the erosive mechanism. The release mechanism involved varied depending on different conditions and different aroma compounds, and at low temperature and relative humidity effective controlled release of aroma compounds was achieved, resulting from intermolecular interactions with the casein micelles. FD-CAEO–CS–PL-NCs showed significantly sensory scores increasing effect of scented tea. The findings will facilitate future developments in the formulation of scented teas, by incorporating aromatic essential oils from fruits and flowers, in the form of essential oil-casein-phospholipid nanocomposites.