Epicarp characterization of coffee fruits by atomic force microscopy

The superficial characterization of epicarp of the coffee fruits was made in two states of development: mature and green. The roughness of the area, and also the line for the parameters of roughness average (Ra) and quadratic root average of the roughness (Rq), were found by means of atomic force microscopy (AFM). In addition, the densities and dimensions of the coffee cells were found. The Ra range of the mature fruit was found to be between 0.03 and 0.19 μm, and for the green fruit it was between 0.23 and 0.38 μm. The Rq range of the mature fruit was found to be between 0.05 and 0.24 μm, and for the green fruit it was between 0.29 and 0.49 μm. These values delimit ranges of roughness for each state of development analyzed, and there is a difference among them without appearing interpolation of the data. It was determined that the cells have ellipsoidal form with an average area of 194.62 μm2, and the density average is 4.206 cell/mm2.