For the condensed
tannin content, the 2nd derivative of the spectral regions 1670–950 (R2 = 0.99; RMSEC= 7.01;
RMSEP= 10.13) and 3750–2125cm−1 (R2 = 0.99; RMSEC= 2.65; RMSEP= 3.97) was correlated with the
concentration estimated by means of methylcellulose and bovine serum albumin assays, respectively.