Influence of Extraction Methods on Dye Intensity of Onion Peels and Its Color Transition in Natural pH-dye Application

抄録

This research investigated in dye intensity which was affected by three extraction methods on two types of onion peels that are bulb onion(BO)and red onion(RO).The results portrayed that RO was the highest content of the dye when it was extracted by soaking method and also revealed the red shade with a maximum lambda (λmax)of 410 nm. Whilst both of RO and BO solutions were continuously changed in their colors from light-pink to darker when the alkaline solution was added into the dye solution. The absorbent spectrum and the color transition kinetic of this extracted onion dyes, as well as the possible use of this extracted dye as a colorant in intelligent packaging technology.