Obtenção e microencapsulação de isoflavonas do melaço de soja para a aplicação em massa fresca

Abstract

Soy and its derivatives present potential in the market because of the presence of bioactive compounds such as isoflavones. There are 12 isoflavone isomers being considered as biologically active isoflavones in aglycone forms. The use of the microencapsulation process has become a viable alternative for the incorporation of bioactive compounds into foods, to be seen as a challenge as to its stability in processed foods. This study aimed to extract the soy molasses isoflavones with different solvents, to test different encapsulating agents with different air intake temperatures and to microencapsulate the extract with the best characteristics through the spray drying method and application in fresh pasta. The solvents used were 80% ethanol and methanol and grain alcohol in concentrations of 50 and 80%, the encapsulating agents were: 18% maltodextrin DE20 (T1), 18% hi-maize (T2) and a mixture of equal proportions of 9% maltodextrin DE20 and 9% hi-maize (T3) with air intake temperatures of 120, 130 and 140 oC, after the selection of the extract with the better characteristics, it was applied in fresh pasta in the form of microcapsules and pure extract. The separation and quantification of isoflavones were performed using high performance liquid chromatography (HPLC), the phenolic compounds were analyzed through the Folin method, the antioxidant activity was determined by the DPPH and ORAC methods. The 50% grain alcohol was the best solvent to extract the isoflavones, this extract presented higher yields of isoflavone aglycones, total isoflavones, phenolics and antioxidant activity. The modified hi-maize starch used by the spray drying method at the air intake temperature of 130 oC was the best encapsulating agent, presenting lower degradation of total and aglycone isoflavones, total phenolics and antioxidant activity. In the fresh pasta it was evaluated the physical and chemical characteristics, the stability of the bioactive compounds of the in natura product and the after cooking in a period of 21 days of refrigerated storage at 4°C sensory and microbiological analyzes as well as the stability of microcapsules throughout storage at room temperature and refrigerated at 4 °C. The formulations of the pastas were, control (T1), with extract (T2) and with microcapsules (T3). The cooked pasta showed a significant degradation of the bioactive compounds in relation to the in natura pasta throughout thestorage in all formulations, although the results show that the masses with the microcapsules were more stable than those with the pure extract, from the fourteenth day the cooking of the masses totally degraded the compounds in all the formulations. The developed pasta are within the Standards of Identity and Quality of Pasta, the psychrotrophic counts increased throughout storage in the control pasta and in those with microcapsules, however the addition of pure extract acted as an antimicrobial, increasing the shelf life of this pasta.