Estimation of Pulp Pigment Content Using Color Space Values in Guava

Abstract

Guava fruits are a rich source of carotenoids, lycopene, and anthocyanin pigments. Colored guava fruits contain a higher concentration of these pigments in comparison to white pulped varieties. The aim of this study was to evaluate the suitability of color reader values for indirect estimation of pigment content in guava fruits. Using the CIELAB’s color space values (L*, a*, b*, C*, and h°), we quantitatively estimated the variations in pulp color (white, red, and purple) across 35 guava genotypes, including hybrids and germplasm. Using spectrophotometric methods, the contents of total carotenoids, lycopene, and anthocyanins were estimated, revealing significant discrepancies among the genotypes. The color value a* was positively correlated with total carotenoids (r_p = 0.81, r_g = 0.85 at p < 0.01), total lycopene (r_p = 0.86, r_g = 0.93 at p < 0.001) and total anthocyanin contents (r_p = 0.56, r_g = 0.52 at p < 0.001). The phenotypic path analysis revealed that total carotenoids (0.31), lycopene (0.51), and anthocyanin (0.13) contents exerted a positive direct effect on color a* value, while genotypic path analysis demonstrated a direct positive effect by lycopene (1.12) and an indirect positive effect by carotenoids (1.02) and anthocyanins (0.63) mediated through total lycopene. These findings suggest that each pigment contributes uniquely to the color a* values, with lycopene being the primary contributor.