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Researches directed to increase the indicators of efficiency and quality during coffee harvest mechanization constitutes an important topic at present time. The determination of the physical-mechanical properties of fruits and fruit-stem system is an indispensable stage during these investigations. In this paper the results on the determination of a group of dimensional, inertial and elastic properties of the fruit-stem system of coffea arabica variety Catuai in different ripening stages, related with mechanical harvesting of this crop, are presented. Also, the bending moment required for the rupture of the fruit-stem union is determined. Methods of processing of digital images, as well as strain gages techniques were used during the investigation. As result of measurement of the different properties, substantial differences on dimensional, inertial and elastic characteristics of green and ripe fruit were found, like as in the bending moment required to fruit detachment and in the detachment patterns. [ABSTRACT FROM AUTHOR]

One of the main difficulties during mechanical coffee harvesting by vibration, consists on the presence of a great percent of green fruits in the harvested mass, that which constitutes a non resolved problem at international level. In this paper, starting from the evaluation of mathematical models of the fruit-stem system dynamics, recommendations are offered about the vibration frequencies to apply in order to achieve a better selectivity during the detachment of ‘arabica caturra’ coffee cherries. [ABSTRACT FROM AUTHOR]