Tannin Extraction from the bark of Pinus oocarpa var. oocarpa with sodium carbonate and
sodium bisulfite. The objective of this study was to evaluate the tannin extraction potential
taken from the bark of Pinus oocarpa var. oocarpa. Nine treatments were performed; the bark
was submitted to extraction using water and water containing different concentrations of
sodium carbonate and sodium bisulfite. The mixture was kept under reflux for two hours. The
extracted contents, the polyphenol found in the extracts (Stiasny number), the tannin yield,
the non-tannin yield and the tannin reactivity through UV method were all determined. The
results have revealed that it is possible to obtain high tannin content (approximately 39%)
from the bark of Pinus oocarpa var. oocarpa by using water extraction when coupled with the
addition of salt. The treatment having (8%) of sodium carbonate provided a greater yield of
condensed tannins, underlining the importance of utilizing this salt with this concentration
during the extraction process. However, the extracts must be evaluated according to o