Effect of blanching pre-treatment on colour and anthocyanin of dried slice purple sweet potato (Ipomoea batatas L)

Purple sweet potato (Ipomoea batatas L) contains many acylated anthocyanins which are beneficial for human health. Purple sweet potato roots are easily damaged due to the high water and nutrient content. To extend the shelf life of purple sweet potatoes can be done by a drying process. The drying process can affect the colour and amount of anthocyanin. The purpose of this study was to analyse the effect of blanching on colour and the amount of anthocyanin of dried slice purple sweet potato. The blanching method studied was steam blanching with a temperature of 70°C-80°C and blanch with boiling water 90°C – 98°C for 2 minutes. To measure the amount of anthocyanin by the pH difference method and measure colour using the chromameter. The results showed that the steam blanching technique produced a higher colour and amount of anthocyanin of dried chips purple sweet potato compared to blanching boiling water. This is because Anthocyanin dissolves in water. The conclusion is to get the colour and the relatively high amount of anthocyanin in dried pieces of purple sweet potato can be done by steam blanching. The implication to prevent browning process when making dried slice purple sweet potato can do steam blanching.