Various bio-wastes from the forest and agricultural industries
have been of interest because of their high levels of residual
nutraceutical components. The re-use of the wastes as value-added
materials is, not only cost-saving, but also environmentally bene-
ficial. Chestnut (Castanea crenata) is a beech family plant natively
grown in the northern hemisphere regions. The nuts contain hard
hull and inner thin skin, both of which are about 10% of the whole
weight of chestnuts (Hwang et al., 2001), and typically removed
to obtain the edible flesh. Those hull and inner skin obtained in
the peeling process are used mainly as fuel (Vázquez et al., 2012).
According to Hwang et al. (2001), tannin content in the inner and
outer shells were significantly different depending on chestnut
varieties, which were in the ranges of 7.83–71.42% and 0.31–2.04%,
respectively.