CHARACTERIZING AND QUANTIFYING ANTHOCYANINS IN RED PEARS AND THE EFFECT OF LIGHT QUALITY ON FRUIT COLOR

The anthocyanin in 'Sensation Red Bartlett' pear skin was characterize d and quantified, and the effect of light quality on fruit color devel opment was evaluated, Anthocyanin concentration was related to fruit c hromaticity values, Pigments were analyzed using high-performance liqu id chromatography (HPLC) and thin-layer chromatography (TLC), One of t wo spots dete cted in the TLC chromatogram did not change color with m olybdate sprays, indicating the possible presence of peonidin, HPLC an alysis confirmed the presence of a major and a minor pigment, which co -eluted with cyanidin 3-galactoside and peonidin 3-galactoside. Monome ric anthocyanins in the pear skin extract were 6.83 mg/100 g of fruit peel, To study light quality, gelatin filters allowing passage of diff erent wavelengths of light were attached over the exposed side of 'Sen sation Red Bartlett' pears 1 month before harvest, Chromaticity was re corded before the filters were attached and after their removal at har vest using the Commission Internationale de l'Eclairage (L:, a*, and b) color space coordinates, Following color measurements, anthocyanin was extracted from individual skin disks, Skin beneath all filters yi elded less hue than the control, Wavelengths that transmit above 600 n m had the largest effect on chroma, a, and b* values, Fruit wrapped i n aluminum foil to obscure all light had the highest luminosity. Wavel engths from 400 to 500 nm gave darker, less chromatic, and redder pear fruit, All treatments yielded higher anthocyanin content than the con trol, There was :1 tendency toward increased anthocyanin content with longer wavelengths, The simple linear regression of the log lanthocyan in content on L value and (a*/b*)L provided an R(2) = 0.41.