Physical and mechanical properties correlation of coffee fruit (coffea arabica) during its ripening

Abstract

There were correlated CIEL*a*b* color coordinates and reflectance in the visible spectrum of the exocarp of Coffea arabica coffee fruits, of the Colombia variety, in nine different development stages, with physical properties such as fresh and dry mass, moisture content and diameters and mechanical properties such as detaching tensile force, fracture force, firmness, deformation and fracture energy in the breaking point. A multivariate linear regression analysis was run to obtain models to accurately predict properties of the coffee fruit from the chromatic coordinates (a* and/or b*) or reflectance for discriminating wave lengths of different stages of development of the coffee fruit, with a confidence level of 99% and a R2 between 78.5 and 99.9%. Results could be used for the design of harvesting and classification systems, as well as for fast determination of coffee quality.