Biochemical Analyses of Star Apple (Chrysophyllum cainito) during Different Ripening Stages.

This study is aimed to determine the changes of the colour, total reducing sugars and total phenolic content (TPC) of two varieties of Jamaican Star apple (Chrysophyllum cainito) -the purple skinned variety and the purple skinned variety- during three different maturation and ripening stages. During ripening, the total reducing sugars content increased significantly for both varieties. Total reducing sugars for the pulp of the purple skinned variety ranged from 85.13 mg/g fresh weight to 252.7 mg/g fresh weight from stage 1 to 3. The green skinned variety ranged from 103.28 mg/g fresh weight to 245 mg/g fresh weight. TPC ranged from 1836.93 μg/g to 719.01 μg/g fresh weight for the purple variety, while for the. green variety TPC ranged from 1990.31 to 887.64 μg/g fresh weight. Total phenols in the pulp for the purple variety ranged from 1096.87 to 215.00 μg/g fresh weight and for the green variety from 854.88 to 244.66 μg/g fresh weights. Colour showed a significant decrease of the L values for the purple variety, while L values for the green variety remained fairly constant during the three stages. Chroma and Hue angle showed significant decreases for the purple star apple while for the green variety, the chroma steadily decreased and the hue angle showed a sharp increases during the three stages.

Key words: colour, total reducing sugars, TPC, Chrysophyllum cainito