Colour Change of Chemically Pretreated Rosehips During Greenhouse and Open Sun Drying

Abstract

The effects of three different chemical solutions (Type I: 2% ethyl oleate, Type II: 2% ethyl oleate + 2% NaOH, Type III: 2% ethyl oleate +2% NaOH + 4% potassium carbonate, w/v) on the final colour of dehydrated rosehips in association with dipping temperature (23°C and 60°C) and drying method (greenhouse drying and open sun drying) were determined. The skin colour was measured by a reflection colorimeter. Secondary colour measures (hue angle, chroma, ratio of redness to yellowness, total colour change and browning index) were also calculated from the measured values of three primary chromatic scales (L, a, b).