Table 1.
Overview of the results.
| α-amylase M | α-amylase S | Pancreatin | Human saliva | |||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 20 °C | 37 °C | 20 °C | 37 °C | 20 °C | 37 °C | 20 °C | 37 °C | |||||||||||||||||||||||||
| Activity (Mean ± SD) |
CV (%) |
Activity (Mean ± SD) |
CV (%) |
Activity (Mean ± SD) |
CV (%) |
Activity (Mean ± SD) |
CV (%) |
Activity (Mean ± SD) |
CV (%) |
Activity (Mean ± SD) |
CV (%) |
Activity (Mean ± SD) |
CV (%) |
Activity (Mean ± SD) |
CV (%) |
|||||||||||||||||
| Panel A – Amylase activities1 as reported by each participating lab | ||||||||||||||||||||||||||||||||
| Lab A | 116.5 | ± | 8.5 | 7.3 | 487.3 | ± | 48.4 | 9.9 | 7.9 | ± | 0.2 | 2.2 | 28.0 | ± | 4.3 | 15.4 | 68.1 | ± | 7.6 | 11.1 | 240.1 | ± | 23.8 | 9.9 | 184.9 | ± | 15.4 | 8.3 | 828.4 | ± | 97.5 | 11.8 |
| Lab B | 107.3 | ± | 12.7 | 11.8 | 340.6 | ± | 11.5 | 3.4 | 5.5 | ± | 0.3 | 5.3 | 17.7 | ± | 0.5 | 3.0 | 57.3 | ± | 1.5 | 2.6 | 169.8 | ± | 7.6 | 4.5 | 271.8 | ± | 12.7 | 4.7 | 702.9 | ± | 72.8 | 10.4 |
| Lab C | 122.7 | ± | 6.7 | 5.5 | 409.0 | ± | 51.7 | 12.6 | 7.9 | ± | 0.9 | 10.8 | 22.7 | ± | 1.9 | 8.3 | 58.8 | ± | 6.4 | 10.8 | 210.3 | ± | 23.4 | 11.1 | 299.5 | ± | 29.4 | 9.8 | 851.1 | ± | 141.1 | 16.6 |
| Lab D | 67.3 | ± | 15.5 | 22.9 | 289.4 | ± | 10.6 | 3.7 | 5.4 | ± | 0.5 | 8.8 | 17.6 | ± | 0.9 | 5.2 | 56.5 | ± | 8.6 | 15.2 | 158.8 | ± | 12.5 | 7.8 | 212.0 | ± | 26.7 | 12.6 | 669.7 | ± | 89.0 | 13.3 |
| Lab E | 105.8 | ± | 15.9 | 15.0 | 376.7 | ± | 57.3 | 15.2 | 6.3 | ± | 1.0 | 15.3 | 16.6 | ± | 2.9 | 17.4 | 53.7 | ± | 6.2 | 11.5 | 174.5 | ± | 23.4 | 13.4 | 298.2 | ± | 33.6 | 11.3 | 914.4 | ± | 133.1 | 14.6 |
| Lab F | – | 395.6 | ± | 44.7 | 11.3 | – | 25.1 | ± | 2.4 | 9.5 | – | 190.1 | ± | 2.9 | 1.5 | – | 809.8 | ± | 59.5 | 7.3 | ||||||||||||
| Lab G | – | 366.6 | ± | 14.7 | 4.0 | – | 23.2 | ± | 1.2 | 5.3 | – | 210.1 | ± | 4.7 | 2.25 | – | 1082.6 | ± | 109.9 | 10.2 | ||||||||||||
| Lab H | – | 439.9 | ± | 41.0 | 9.3 | – | 26.1 | ± | 1.5 | 5.8 | – | 225.0 | ± | 9.0 | 3.99 | – | 895.4 | ± | 95.2 | 10.6 | ||||||||||||
| Lab I | – | 363.0 | ± | 25.2 | 7.0 | – | 15.1 | ± | 0.2 | 1.0 | – | 220.3 | ± | 27.0 | 12.3 | – | 1109.0 | ± | 201.6 | 18.2 | ||||||||||||
| Lab J | – | 392.0 | ± | 39.1 | 10.0 | – | 20.7 | ± | 1.5 | 7.4 | – | 200.0 | ± | 4.0 | 2 | – | 798.7 | ± | 54.6 | 6.8 | ||||||||||||
| Lab K | – | 328.3 | ± | 39.5 | 12.0 | – | 26.1 | ± | 1.3 | 5.0 | - | 195.7 | ± | 10.7 | 5.5 | – | 728.1 | ± | 18.8 | 2.6 | ||||||||||||
| Lab L | – | 479.5 | ± | 61.4 | 12.8 | – | 29.2 | ± | 2.6 | 8.9 | – | 282.8 | ± | 12.4 | 4.4 | – | 970.1 | ± | 170.1 | 17.5 | ||||||||||||
| Lab M | – | 31.5 | ± | 0.52 | 1.72 | – | 45.2 | ± | 4.42 | 9.72 | – | 352.3 | ± | 45.32 | 12.92 | – | 1046.7 | ± | 61.8 | 5.9 | ||||||||||||
| Activity (Mean ± SD) | 103.7X ± 21.4 | 389.0B ± 58.9 | 6.6Z ± 1.2 | 22.3D ± 4.8 | 58.9Y ± 5.5 | 206.5C ± 33.8 | 253.3W ± 52.1 | 877.4A ± 142.7 | ||||||||||||||||||||||||
| Activity in IU3 (Mean ± SD) | 377.3 ± 57.1 | 21.6 ± 4.7 | 200.3 ± 32.8 | 851.1 ± 138.4 | ||||||||||||||||||||||||||||
| Panel B – Assay repeatability and reproducibility | ||||||||||||||||||||||||||||||||
| Repeatability (CVr, %) | 14.0 | 10.0 | 9.6 | 8.9 | 11.0 | 7.7 | 9.7 | 12.5 | ||||||||||||||||||||||||
| Reproducibility (CVR, %) | 20.6 | 15.1 | 18.8 | 21.3 | 9.3 | 16.4 | 20.6 | 16.3 | ||||||||||||||||||||||||
| Panel C – Relationship between activities measured at 37 °C vs. 20 °C | ||||||||||||||||||||||||||||||||
| Ratio of activity at 37 °C vs. 20 °C (Mean ± SD)4 | 3.7 ± 0.5 | 3.1 ± 0.4 | 3.2 ± 0.3 | 3.2 ± 0.7 | ||||||||||||||||||||||||||||
| Global average5 of the activity ratios between 37 °C and 20 °C = 3.3 ± 0.3 (95% CI: 2.9 to 3.7) | ||||||||||||||||||||||||||||||||
1Amylase activity unit definitions: assay at 20 °C—one unit liberates 1.0 mg of maltose from starch in 3 min at pH 6.9 and 20 °C; assay at 37 °C—one unit liberates 1.0 mg of maltose from starch in 3 min at pH 6.9 and 37 °C.2Excluded from calculation of activity mean and SD, CVr, CVR and from the statistical analysis. 3Conversion of mean α-amylase activities obtained using the newly optimized protocol (at 37 °C) into International Units (IU) by multiplying activity values based on Bernfeld’s original definition by the conversion factor 0.97. 4Average of the ratios of activity at 37 °C vs. 20 °C reported by laboratories A to E for each test product. 5Average of the ratios of activity at 37 °C vs. 20 °C of all test products as reported by laboratories A to E.
A–DWithin a row, denote statistically significant differences between the products tested at 37 °C (p < 0.0001). W-Z Within a row, denote statistically significant differences between the products tested at 20 °C (p < 0.0001).