The Effects of pH and Heat Treatment Processing on the Stability of Natural Food Colours used in Dairy Products

Abstract

This study was carried out to investigate the effects of pH and heat treatment processing on stability and natural food colours used in dairy products. A repeated laboratory experiment was conducted in which loss of colour intensity or change in shade of natural food colours used in acid and nearly neutral dairy products at low and at boiling temperatures was investigated. Five (5) natural food colours out of the fourteen (14) in the study were applied to small-scale industrial processing of UHT milk drinks and laboratory-scale yoghurt making. All the fourteen natural food colours studied were stable to pH changes. Only one natural food colour (Beet root) was destroyed at boiling temperatures while two of the colours (Beet root and Cochineal) were destroyed at UHT (136ºC/4Seconds) processing. It was then concluded that pH changes and Heat Treatment processing do not contribute very much to the destruction of natural food colours used in dairy products.

The Journal of Food Technology in Africa Volume 5 Number 2 (April - June 2000), pp. 59-61



KEY WORDS:

pH, Heat, Stability, Food Colours