Efeitos da temperatura e da adição de açúcares na solubilidade dos acetatos de butila e etila em solução aquosa

Abstract

Iinteractions between flavor molecules and other compounds are often investigated in binary and ternary systems (for example, water, aroma compounds, carbohydrates) to characterize specific release mechanisms. The influence of different types of sugar should be noted that in situations where they are part of the solution of interest. However, the release of aromas complex food matrices is difficult to predict and the knowledge of data solubility are useful in the development of industrial processes. Solubilities of butyl acetate and ethyl acetate from pure water and aqueous solutions of low viscosity was investigated. Aqueous solutions were prepared with sucrose, glucose and fructose in concentration range 10-30 g L-1. The static method was used and the concentrations of aroma compounds in thermodynamic equilibrium was monitored by gas chromatography with a flame ionization detector (CG -FID). The experiments were performed in the temperature range of 5-25 ° C, using jacketed Pyrex glass vessels connected in series, called cells, interconnected by a latex hose and connected to a thermostatic bath to control the temperature during the experimental trials. The samples were shaked for 2 h, then they were kept at rest for 24 h and only after these step, triplicate sampling of 1μL injection were carried out in the gas chromatograph. Solubilities of butyl acetate and the ethyl acetate mixtures and the pure water increased with decreasing temperature. The flavour components are retained more extensively in the presence of glucose solutions in comparison with that of pure water. In some situations the size of the sugar molecule showed negatively influence on the solubility of the esters, suchs as sucrose, that due to its higher molecular mass competed with the ester molecule by water. All aqueous solutions had a similar behavior as the sugar concentration was increased when, although it was expected that the molecular weight of sugar could have an influence on the equilibrium concentration. The acetate-water-sugar systems thermodynamic equilibrium reached time to time equal to 22 h, both as the butyl acetate to ethyl acetate. The gas chromatography was found to be valid to determine the solubility of the esters in pure water and in aqueous solutions. Besides the experimental data, it was also possible to correlate the experimental data by estimating parameters of four equations. Results solubility of ethyl acetate in water is in agreement with the literature. The experimental solubility and solubility available in the literature of butyl acetate in pure water at 25 °C are equal to 0.5917 g 100g-1 and 0.5928 g 100g-1, respectively. The value experimental solubility of ethyl acetate in pure water was equal to 7.1504 g 100g-1 and the literature value is 7.270 g 100g-1. The correlation of the experimental data set in software were satisfactory.