Effect of storage temperature on the microbial and color stability of banana purée with addition of vanillin or potassium sorbate / Efecto de la temperatura de almacenamiento en la estabilidad microbiológica y en el color del puré de plátano con la adición de vainillina o sorbato de potasio

Abstract

The microbial and color changes during storage at different temperatures (15, 25 and 35 °C) of ba nana purée preserved by the combination of a blanching, reduced pH (3.4) and water activity ( aw, 0.97) and the addition of 1000 or 3000 ppm of vanillin (VA) or 1000 ppm potassium sorbate (PS) were evaluated and compared. The use of 3000 ppm VA or 1000 ppm PS inhibited for at least 60 days of storage the native flora of the banana purée at any of the temperatures studied. The addition of 1000 ppm VA was not enough to stop the microbial growth. However, at 15 °C the growth was delayed 16 days. In the presence of 3000 ppm VA or 1000 ppm PS the banana purée stored at 15, 25 and 35 °C presented several color changes that contributed to browning. The rate of browning was greater in samples with VA than in those formulated with PS, but the activation energy was 10% lower in the former systems. An analysis of the transition state parameters revealed that Gibbs free energy was similar, indicating that the mechanism of browning did not change in the presence of one antimicro bial or the other.