The effect of Initial pH and temperature during storage on stability of pigment extract Mandarin orange peel (Citrus reticulata)

Abstract

The orange peel of Mandarin oranges contains carotenoid compounds which have potential as natural yellow  and orange dyes and also as a source of antioxidants. The dye obtained from Mandarin orange peel has  unstable properties. The purpose of this study was to know the effect of initial pH and temperature during  storage on the stability of the Mandarin orange peel dye extract and determine the best initial pH and  temperature during storage to maintain the stability of the Mandarin orange peel dye extract (Citrus  reticulata). The experiment of this study used Completely Randomized Design with two factors. The first factor  is initial pH consisting of three levels: pH 4, 7, and 10. The second factor is temperature during storage consisting of two levels: 4±3ºC and 28±3ºC. The results showed that initial pH had significant effect (P<0.01)  on carotenoids, antioxidant capacity, brightness (L*), redness (a*), and yellowess (b*). The temperature during storage had significant effect on carotenoids, antioxidant capacity, brightness (L*), and yellowess (b*)  but had not significant effect (P>0.05) on redness (a*). The dye extract of Mandarin orange peel was more  stable at the storage conditions of pH 7 (neutral) and cold temperature (4±3ºC) during 4 weeks storage with  decreased of carotenoids, antioxidant capacity, increase in brightness (L*), decrease in redness (a*), and  decrease in yellowess (b*) successively was 42,96%; 21,02%; 26,36%; 20,89 dan 16,89%.