Discussion
The pH of the pulp after two months of fermentation
was near 4, where bacterial growth is inhibited (Ryser et al.,
1997). However, pH values greater than 4.50 have been
reported for barley, with high values of lactic and acetic
acid, which indicates good fermentation (Hristov and
McAllister, 2002). Despite the high moisture content in
the silage, because there was no butyric acid, the coffee
pulp silage did not have unpleasant smell or taste, which
might have been rejected by the animals. A high value of
lactic acid (47.38 g kg−1
DM) was found, higher than those
found for corn and sorghum silage (Juarena, 2008). The
high content of lactic acid indicates that there were enough
soluble carbohydrates in the coffee pulp, which has a sweet
taste due to the presence of a great amount of sugars, besides
the 50 g molasses kg−1
pulp that was added, thus increasing
the content of soluble carbohydrates. Because of this, it
is essential to determine if it is necessary to add molasses
to the coffee pulp before ensiling, or if its addition can be
omitted for practical and economic reasons.
The ash values were higher than those found by
Figueroa and Mendoza (2010), who reported an average of
66 g kg−1
, and those found by Bautista et al. (2005), who
reported 74 g kg−1
for unfermented coffee pulp and 69 g kg−1
for coffee pulp ensiled with 50 g molasses kg−1
coffee pulp.
The high ash values found in this study could be due to
the hand-picked method and the pulping process, where it
could have been contaminated with different minerals from
the soil.