Influência da adição de biopolímeros e de diferentes técnicas de gotejamento na encapsulação de alfa-tocoferol por gelificação iônica

Abstract

Bioactives are components that promote human health benefits, they can be naturally present in some foods, but they can also be derived as ingredients in other food matrices developing this type of product. However, these compounds have limitations regarding their use, as they are unstable to the presence of light, oxygen, changes in pH and temperature. Therefore, it is necessary to develop techniques for protecting these compounds, such as microencapsulation methods. The method used for microencapsulation of α-tocopherol was ionic gelation using alginate combined with other biopolymers. To define the best microencapsulation conditions for α-tocopherol, the work was carried out in stages. In the first stage, emulsions were produced using alginate, combined with other materials (gum arabic, cashew gum, inulin, whey protein isolate and maltodextrin). These emulsions were characterized and analyzed for rheology. The formulations using an inulin and an independent cashew gum good homogeneity (span = 3.85) and good drop dispersion (microscopy), respectively, and for this reason, were the biopolymers selected for a second stage of the work. In this second stage, as emulsions they were atomized using two different types of nozzle (pressurized and ultrasonic air) for the production of α-tocopherol microbeads. These were characterized by FTIR-ATR, encapsulation efficiency, morphology, size distribution and release profile. Regarding the encapsulation efficiency, a higher concentration of α-tocopherol was observed in the microbeads produced using ultrasonic atomization. The different methods used directly interfered with the size of the microbeads produced. It was noticed that as microbeads produced from pressurized air source close to 130 μm and those produced by ultrasonic energy generated between 70 and 90 μm. Regarding the release profile, there was no significant difference regarding the stability of the microbeads produced by the different methods. In view of these results, the third stage of the project was carried out, in which the use of ultrasonic energy for the production of microbeads was defined. With that, alginate + inulin and alginate + cashew gum models were maintained, both 1.75% (w/v) + 0.5% (w/v), as microbeads were produced and then lyophilized. Again, microbeads were characterized. There was an increase in encapsulation efficiency when inhaling an inulin or a cashew gum in relation to pure alginate, from 76.31% to 80.83 and 78.68%, respectively. When kept at the highest temperature for 30 days, the complementary materials also contributed to a greater stability of the asset in the microbeads. At 40 °C to alginate and dissipated inulin microbeads, the highest antioxidant activity (11.85%) at the end of the study period. When analyzing the bioaccessibility of α-tocopherol, it was found that the presence of inulin resulted in greater bioaccessibility (58.60%), compared to microbeads produced using only alginate (16.22%). With this, we can conclude that it is possible to develop a controlled and efficient transmission system using alginate and complementary biopolymers that are compatible through atomization by ultrasonic energy, and that they promote improvements in the properties of microparticles allowing their incorporation into different food matrices.