Development of method for measurement of visible absorption spectrum using pigments extracted from colored vegetables

Abstract

The relationship between the absorption of visible light and visible colors was examined by using colorful vegetables. Ten different vegetables were used to determine the desirable density of solvent and measurement condition. It was decided that the best way to examine the relationship is to use paprikas (red ones and yellow ones) and green peppers cut into a strip of 0.5g and dissolved in 4 ml ethanol, and to leave them for 20 minutes until their plant pigments should be extracted. It was shown that both yellow pigments and red ones have a short-wavelength spectrum. The absorption spectrum of green pepper has a noticeable maximum absorption around 670 nm. This shows that a green pepper will turn red once its amount of chlorophyll decreases. By using some pigments taken from vegetables such as paprika and green pepper, we developed a suitable method for understanding the relationship between the absorption of visible light and visible colors.