Effect of temperature on the evolution of colour during the maceration of fruits in liquor

Abstract

The effect of temperature on the kinetics of pigment extraction during the maceration of different fruits (raspberry, blackberry, and cranberry) into a commercially available hard spirit (orujo, with 42% v/v ethanol) was evaluated. The analytical method used was UV-Vis spectrophotometry. The initial extraction rate showed an Arrhenius-type dependence with apparent energy activation of 28.8, 69.8, and 55.6 kJ/mol, respectively. Furthermore, a study about the evolution of the colour (from colourless to reddish colour appearance) during the soaking process was done by calculating the CIE tristimulus values (X, Y, Z) for illuminant C, until reaching the apparent stabilisation of colour, which occurs after about two to four weeks for the studied temperatures (5, 23, and 40°C). Studies about the evolution of colour in the soaking process of this kind of fruit liquors can lead to a better understanding of this process, and thus to a better control over the mechanisms underlying it.

Keywords

• keywords: ethanol
• spectral method
• spirit
• anthocyanins
• kinetics