Desenvolvimento e caracterização de micropartículas poliméricas naturais contendo extrato de grãos de café verde (Coffea arabica L.)

Abstract

Green coffee has active properties against several diseases, mainly attributed to chlorogenic acids, with 5-O-caffeoylquinic acid (5-ACQ) being the most important among them. The green beans have higher concentrations of 5-ACQ, when compared to roasted grains, this degradation occurs due to the high temperature used in the process. Degradation of 5-ACQ may also occur under various processing and storage conditions. In addition, it presents low bioavailability which interferes with the efficiency of its properties and applications. This work was carried out aiming at the protection of green coffee bean extract by microencapsulation in natural chitosan (Q) polymer systems. Chitosan microparticles were prepared with xanthan gum (GX) and sodium tripolyphosphate (TPP) as crosslinking agents. The microparticles were characterized for particle size, scanning electron microscopy, encapsulation efficiency, spectroscopy, thermogravimetric analysis, release profile and mucoadhesive test. The results showed that the green coffee extract had 110.15 μg / mg of 5-ACQ, in addition to high antioxidant activity. In the characterization of the microparticles, we observed irregular, squamous, friable forms and the Q/GX particles were larger than the Q/TPP and showed different behavior in size after addition of the extract. The efficiency of encapsulation of 5-ACQ was influenced by the crosslinking agent used, being the microparticles of Q/TPP the ones that obtained higher rates of encapsulation (74.04%). The physico-chemical analysis demonstrated the entrapment of the extract by the microparticles and that the obtained polymer systems are microspheres, besides possessing greater stability than the extract in the free form. The release profile of 5-ACQ in simulated gastric fluid was also influenced by the crosslinking agent used, being the microparticles of Q/TPP the ones that released higher percentage. In simulated intestinal fluid the release was gradual and similar for both polymer systems. Regarding the interaction with mucin, all proposed microparticles have a high mucoadhesive capacity of 83.58 and 87.19%. In this work, it was possible to develop and characterize microparticles containing green coffee bean extract, which have promising properties to increase the stability and bioavailability of 5-ACQ, and thus, make the extracts more efficient and practicable.