Dados do Trabalho

Título

CHITOSAN-BASED NANOCAPSULES LOADED WITH LYCOPENE: EFFECT OF CHITOSAN MOLECULAR WEIGHT ON PHYSICOCHEMICAL, RHEOLOGICAL, BIOACCESSIBILITY AND ANTIOXIDANT STABILITIES

Introdução

Lycopene is a carotenoid with antioxidant, antimicrobial, antitumor and anti-inflammatory properties, allowing prevention and treatment of cardiovascular, degenerative and tumor diseases. However, this compound is barely used in food industry due to its instability. Therefore, it is important to develop new carrier systems in order to preserve the bioactive properties of this compound. Nanoencapsulation using depolymerized chitosan as wall material is promising due to its effect on solubility, viscosity, particle size, biodegradability, biocompatibility, non-toxicity, antimicrobial activity and mucoadhesion. Therefore, the objective of this study was to develop nanoemulsions for the preservation of lycopene using depolymerized chitosan as wall material, and to verify the effect of chitosan depolymerization by oxidative pathway on the nanocarriers properties.

Material e Métodos

The chitosan was subjected to oxidative depolymerization to reduce the molecular weight, obtaining 45, 100, 135 and 200 kDa. Four nanoemulsions were produced using the emulsification method, NCH-45, NCH-100, NCH-135 and NCH-200 corresponding to chitosan of different molecular weight. The emulsification parameters were chitosan concentration (0.55% w/v), agitation rate (11,500 rpm), time (30 min), bioactive concentration (3% v/v) and tween® 80 surfactant (5% w/w of chitosan). The characterization of the nanocapsules was determined by particle size, polydispersity index, Zeta potential, viscosity and surface tension. The bioaccessibility of nanoencapsulated lycopene was evaluated by in vitro analysis of the gastrointestinal tract. The morphology was analyzed with transmission electron microscopy (TEM). The stability of the antioxidant activity was determined using 2,2-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical capture methods.

Resultados e Discussão

All nanoemulsions showed high encapsulation efficiency (≥93.89%) and remained stable over 35 days without phase separation. The low molecular weight nanoemulsion NCH-45 showed the best steric stability and the highest percentage of bioaccessibility (17.9%).

Conclusão

Furthermore, all nanoemulsions showed good capacity in the antioxidant activity of the lycopene-rich lipid extract. They also presented similar viscosity and surface tension characteristics. As a result, the developed nanoemulsions were capable of preserving the antioxidant activity of lycopene, which allows several applications in food industry.