[Coffee pulp and hulls. XI. Chemical characteristics of silaged coffee pulp with Napier grass (Pennisetum purpurem) and corn plant (Zea mays)]. / Pulpa y pergamino de café. XI. Characterísticas químicas de la pulpa de café ensilada con pasto Napier (Pennisetum purpureum) y planta de maíz (Zea mays)

Various physical and chemical changes that occur during the process of preparation of coffee pulp silage with the addition of molasses and forage, were identified and measured quantitatively. Three types of silage were prepared in duplicate in laboratory concrete silos, 45 cm wide and 50 cm high. The silages contained the following components: coffee pulp (EPC), pulp and Napier grass (EPCN), and pulp with corn fodder (EPCM). On a fresh basis, the last two contained equal proportions of coffee pulp and forage. Around 16% molasses were aded to all silages. Time of ensiling was 132 to 141 days. In order to determine the physical changes, the silage was weighed at the start and end of the ensiling period; the pH was determined at the end of same, and the drained liquids were measured during the experimental period. To determine the chemical changes, analyses were carried out on the various components used and on the mixtures ensiled at the start and at the end of the experimental period. The pH of the silage was 4.5, 4.3, and 3.8, and the losses of dry matter 10.6, 25.2, and 33.3% for the three types of silages, respectively. These percentages suggest that a better fermentation took place in those silages containing forages. The better fermentation of EPCN over EPC was due to the Napier grass which provided greater amounts of chemical components susceptible of fermentation than those found in coffee pulp. The quality of EPCM was superior due not only to the presence of corn fodder, which produced an effect similar to that of Napier grass, but also due to the fact that the coffee pulp used in this case contained the greater concentrations of soluble carbohydrates and lower levels of lignin than the coffee pulp used alone or with Napier grass. As a result of the fermentation process, in all three types of silage a decrease in dry matter content, of cellular contents and soluble carbohydrates was observed, as well as an increase in cellular walls and its components, and of protein. The magnitude of these changes was found to be directly related to the losses in dry matter. From the results of this research, it was concluded that the addition of forage improves the chemical characteristics of silage prepared from coffee pulp.