Table 6. Quantitation of protein variants from milk samples.
| Jersey milk | Holstein milk | T-test | ||||||
|---|---|---|---|---|---|---|---|---|
| Protein | Average RT (min) | Average Response | CV Response (%) | Average RT (min) | Average Response | CV Response (%) | p-value Response | significance |
| aLA-B | 16.83 | 3.1430 | 2.1924 | 17.00 | 2.6865 | 3.7495 | 0.0006 | *** |
| aLA-B-G | 15.61 | 0.2639 | 13.5836 | 15.42 | 0.1970 | 6.2683 | 0.0236 | * |
| aS1CN-B-8P | 15.46 | 1.5917 | 3.9823 | 15.61 | 1.5511 | 7.5522 | 0.6165 | n.s. |
| aS1CN-B-9P | 16.54 | 0.4291 | 6.2196 | 16.68 | 0.3363 | 3.3860 | 0.0015 | ** |
| aS2CN-A-10P | 7.12 | 0.5305 | 3.8224 | 6.92 | 0.5573 | 6.3023 | 0.2962 | n.s. |
| aS2CN-A-11P | 7.32 | 0.9330 | 6.4905 | 7.43 | 0.6549 | 4.4493 | 0.0004 | *** |
| aS2CN-A-12P | 7.82 | 2.2673 | 1.9770 | 7.95 | 1.6973 | 4.0134 | 0.0000 | *** |
| aS2CN-A-13P | 8.13 | 1.1416 | 2.4312 | 8.43 | 0.8545 | 5.0902 | 0.0001 | *** |
| aS2CN-A-14P | 8.31 | 0.5240 | 2.1923 | 8.66 | 0.3464 | 6.9380 | 0.0000 | *** |
| bCN-A1-5P | 20.12 | 5.1872 | 1.8887 | 20.16 | 6.9617 | 4.9996 | 0.0001 | *** |
| bCN-A2-5P | 21.04 | 12.8962 | 2.8863 | 21.19 | 11.2693 | 5.2077 | 0.0067 | ** |
| bCN-B-5P | 19.22 | 4.7576 | 4.2614 | 19.36 | 2.0470 | 1.7351 | 0.0000 | *** |
| bCN-I-5P | 23.50 | 0.0932 | 2.4644 | 23.42 | 0.0987 | 4.2572 | 0.2000 | n.s. |
| bLG-A | 22.87 | 5.3522 | 5.7464 | 22.98 | 4.2130 | 4.3259 | 0.0015 | ** |
| bLG-B | 20.85 | 2.4886 | 3.4503 | 20.99 | 2.8132 | 4.8285 | 0.0128 | * |
| bLG-D | 23.31 | 0.1020 | 5.9428 | 23.62 | 0.0847 | 10.1951 | 0.0353 | * |
| BSA | 15.44 | 0.9757 | 4.4888 | 15.62 | 0.9283 | 6.7009 | 0.3224 | n.s. |
| kCN-A-1P | 6.72 | 0.3971 | 3.3511 | 6.67 | 1.5740 | 5.4925 | 0.0000 | *** |
| kCN-A-2P | 6.41 | 0.0999 | 8.1087 | 6.65 | 0.1424 | 4.8685 | 0.0005 | *** |
| kCN-B-1P | 8.50 | 2.7025 | 3.0301 | 8.73 | 0.9285 | 3.3471 | 0.0000 | *** |
| kCN-B-1P-G | 7.30 | 0.0917 | 7.0158 | 7.48 | 0.1254 | 12.8383 | 0.7929 | n.s. |
| kCN-B-2P | 9.12 | 0.1667 | 8.2451 | 8.96 | 0.0920 | 12.5636 | 0.0060 | ** |
Milk samples were spiked with myoglobin IS and run using our optimum LC-MS parameters in triplicates. Average retention times (RTs) and normalised responses based on peak area are reported. Precision was evaluated across repeated measurement results and expressed by coefficient of variation (CV) of replicate results. A Student t-test was performed to compare the normalised response of proteins of interest from Jersey milk with that of Holstein milk proteins. n.s. not significant,
* p-value < 0.1,
** p-value <0.01,
*** p-value < 0.001.