Microencapsulação da hortelã-pimenta (Mentha piperita L.) utilizando a técnica de coacervação complexa

Abstract

Microencapsulation is an effective technique for protecting bioactive compounds, such as essential oils, from external factors like light, oxygen, and temperature. Using the complex coacervation method, it employs biopolymers such as gelatin and gum arabic to form a protective barrier. This ensures greater stability and allows for the controlled release of the encapsulated substances. This study aimed to develop and characterize microcapsules containing peppermint essential oil, with the objective of improving its stability, protection, and durability under adverse environmental conditions. For this purpose, gum arabic and gelatin were used as wall materials, along with the enzyme transglutaminase (TGL) as a crosslinking agent to enhance the mechanical resistance of the microcapsules. Formulations were prepared with 25%, 50%, and 75% essential oil concentrations relative to the biopolymers, and were evaluated in terms of morphology, chemical structure, and thermal behavior.The results demonstrated that the complex coacervation method was effective in forming spherical microcapsules. Morphological analysis by scanning electron microscopy (SEM) revealed that the capsule structure was influenced by the ratio between wall materials, as well as by crosslinking and lyophilization conditions. The microcapsules exhibited an average diameter below 130 μm, with low uniformity, particularly in samples with higher oil concentrations and the presence of TGL, which promoted the formation of larger particles.Fourier-transform infrared spectroscopy (FTIR) confirmed the presence of characteristic functional groups of gelatin, gum arabic, and peppermint essential oil in the microcapsule matrix. Thermogravimetric analysis (TGA) showed that increasing the oil concentration led to greater mass loss and an earlier onset of thermal decomposition. On the other hand, crosslinking with transglutaminase contributed to improved thermal stability of the microcapsules.The results indicate that the microencapsulation technique employed is effective in protecting volatile and heat-sensitive compounds, demonstrating potential for applications in the food, cosmetic, pharmaceutical, and agricultural industries