Dados do Trabalho

Título

Baru water- oil emulsion as ascorbic acid carrier: kinetic and thermal stability

Introdução

Ascorbic acid (AA) is highly soluble in water and is easily oxidized in the solubilized form. In this way, emulsification can be used to promote its protection. Among vegetable oils, baru oil has gained attention due to its composition, mainly due to the content of bioactive compounds. Therefore, the objective of this research was to evaluate the kinetic and termal stability of water-in-oil (W/O) emulsions, containing gelatin in the aqueous phase and different concentrations of AA (0 , 10, 20 and 30% w/w) and in the continuous phase baru oil and PGPR, totaling 4 treatments.

Material e Métodos

Samples were prepared in a high-speed homogenizer and stored at 25 °C and 4 °C for 7 days. The mean size of the dispersed droplets were analyzed using microscopic images and determined using the software (Carl Zeiss Vision AxioVision Viewer 4.8). The creaminess index (CI) was determined to evaluate the macroscopic stability of the emulsions. The thermal properties analysis was conducted using a nano differential scanning calorimetry (NanoDSC). The results were subjected to analysis of variance (ANOVA) and Tukey test (α=0.05).

Resultados e Discussão

Regardless of the temperature studied,the mean droplet size was influenced by storage time (p < 0.05), ranging from 3.0 μm to 4.3 μm. The storage time reduced the kinetic stability of the emulsions (W/O) that presented larger droplets, favoring colloidal destabilization phenomena, such as flocculation, which were observed in the microscopic images. However, for the macroscopic analysis of the emulsions, the kinetic stability was not influenced by the AA concentration and the storage time (p > 0.05), and no phase separation was observed. The NanoDSC results suggest that emulsions produced with 1 mg.mL-1 of gelatin and 20-30% AA were significantly more stable compared to emulsions without added gelatin or with 10% AA. The results showed that it is possible to develop emulsions with baru oil and AA stable at refrigeration and room temperatures (25°C).

Conclusão

Therefore, emulsions containing a high concentration of ascorbic acid (up to 30% w/v dispersed in the aqueous phase) and baru oil have potential for application in the food industry, meeting consumer demand for healthier products.