Table 2.
Chemical composition in terms of cellulose, hemicellulose, Klason lignin, and ash content of the defatted almond skin DAS, the insoluble residues (R-160 and R-180) obtained from SWE, and the bleached residues (BR-160 and BR-180) submitted to different bleaching cycles (1–4) (mean values ± standard deviation).
| Sample | Cellulose (%wt.) | Hemicellulose (%wt.) | Klason Lignin (%wt.) | Ash (%wt.) |
|---|---|---|---|---|
| DAS | 9.8 ± 0.3 | 11.6 ± 0.5 | 17.4 ± 0.2 | 5.1 ± 0.1 |
| R-160 | 18.6 ± 0.9 b | 6.4 ± 0.3 a | 45.2 ± 0.5 b | 2.3 ± 0.1 a |
| R-180 | 20.9 ± 0.2 a | 5.1 ± 0.1 b | 51.2 ± 0.3 a | 2.7 ± 0.6 a |
| BR-160-1 | 35.0 ± 3.0 a,1 | 13.4 ± 0.9 b,1 | 22.0 ± 3.0 a,2 | 15.0 ± 1.0 c,1 |
| BR-160-2 | 40.0 ± 4.0 a,2 | 17.5 ± 1.9 a,1 | 18.9 ± 1.9 b,2 | 17.0 ± 4.0 bc,1 |
| BR-160-3 | 40.0 ± 4.0 a,2 | 15.0 ± 3.0 ab,1 | 15.0 ± 2.0 c,2 | 18.0 ± 4.0 b,2 |
| BR-160-4 | 40.0 ± 3.0 a,2 | 13.6 ± 0.7 ab,1 | 13.6 ± 0.1 c,2 | 25.0 ± 3.0 a,1 |
| BR-180-1 | 35.6 ± 1.8 b,1 | 9.3 ± 1.2 b,2 | 33.0 ± 2.0 a,1 | 10.4 ± 0.1 c,2 |
| BR-180-2 | 52.0 ± 2.0 a,1 | 13.5 ± 0.5 a,2 | 22.5 ± 0.7 b,1 | 17.0 ± 5.0 b,1 |
| BR-180-3 | 49.9 ± 0.8 a,1 | 10.0 ± 2.0 b,1 | 22.0 ± 4.0 bc,1 | 26.3 ± 0.5 a,1 |
| BR-180-4 | 49.6 ± 0.6 a,1 | 13.9 ± 1.2 a,1 | 16.7 ± 0.7 c,1 | 22.0 ± 7.0 ab,1 |
Different subscript letters indicate significant differences between samples of the same group (insoluble residues R; bleached residues BR-160 or BR-180). Different numbers indicated significant differences between BR-160 and BR-180 samples at the same bleaching cycle (Fisher test, p < 0.05).