Vegetable Tannins as Chrome-Free Leather Tanning

Table 2

Percent yield of extracted tannins from Cassia singueana bark.

No. of trials	Bark powder concentration (g/L)	Extraction temperature (°C)	Extraction time (min)	Extract tannins (g)	Extracted yield (%)
Trial 1	60	80	90	15.54	27.56
Trial 2	40	60	60	3.6	9
Trial 3	80	60	60	10.25	12.81
Trial 4	80	100	60	19.25	24.06
Trial 5	80	100	120	29.46	36.83
Trial 6	80	60	120	16.88	21.1
Trial 7	40	60	90	5.73	14.32
Trial 8	40	100	120	12.8	32
Trial 9	40	100	60	8.2	20.5
Trial 10	60	60	120	9.15	15.25

The significance of bold in this table is just to indicate the trial attained maximum %yield of extract.