Optimization of Keratin Hydrolysate Extraction from Tannery Sheep Hair Waste

Table 3

Total nitrogen and protein content determination using the Kjeldahl method.

Run no	0.1 NHCl consumed average ± SD	% Nitrogen content average ± SD	% Protein content average ± SD
Acid titration to determine nitrogen
1	101.5 ± 2.0	14.2 ± 0.3	88.9 ± 7.2
2	98.8 ± 2.6	13.8 ± 0.4	86.6 ± 2.2
3	97.3 ± 2.5	13.6 ± 0.3	85.2 ± 1.9
4	95.2 ± 2.8	13.3 ± 0.6	83.3 ± 3.5
5	100.0 ± 2.5	14.0 ± 1.5	87.5 ± 9.1
6	81.3 ± 2.9	11.4 ± 1.4	71.2 ± 8.8
7	96.2 ± 2.8	13.5 ± 0.7	84.2 ± 4.6
8	104.5 ± 1.0	14.6 ± 0.4	91.5 ± 2.3
9	99.8 ± 1.9	14.0 ± 0.2	87.4 ± 1.5
10	98.0 ± 2.2	13.7 ± 0.4	85.8 ± 2.6
11	99.8 ± 2.9	14.0 ± 0.5	87.4 ± 2.8
12	102.2 ± 2.5	14.3 ± 0.7	89.4 ± 4.16
13	93.7 ± 2.8	13.1 ± 0.7	82.0 ± 4.4
14	98.5 ± 3.0	13.8 ± 1.0	86.2 ± 6.5
15	86.3 ± 1.0	12.1 ± 0.4	75.6 ± 2.5
16	91.7 ± 1.8	12.8 ± 0.8	80.3 ± 5.2
17	101.2 ± 2.5	14.2 ± 0.4	88.6 ± 2.3
18	102.3 ± 1.8	14.3 ± 0.6	89.6 ± 3.7
19	92.7 ± 6.7	13.0 ± 1.0	81.2 ± 6.3
20	96.8 ± 2.6	13.6 ± 0.4	84.8 ± 2.3