Table 2.
Quantitative data of lactose content and thermal markers evaluated, and label composition of all UHT milk samples collected
| Brand | Matrixa | Lactoseb (g 100 mL−1) Mean (± sd) |
Thermal markers | Nutritional compositiona (g 100 mL−1) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Total HMFc (µmol L−1) | WPNIc (mg WPN mL−1) | Lactuloseb (mg 100 mL−1) | Protein | Fat | Lactose | Glucose | Galactose | ||||||
| Mean (± c.i.) | % CVintra | Mean (± c.i.) | % CVintra | Mean (± sd) | % CVintra | ||||||||
| 1 | REG | 4.78 (± 0.02) | 11.85 (± 0.49) | 82.1 | 4.28 (± 0.75) | 9.8 | 34.12 (± 0.63) | n.q | 3.3 | 1.1 | 4.7 | n.i | n.i |
| LF | 0.1177 (± 0.0003) | 44.68 (± 1.22) | 4.92 (± 0.75) | n.q | 3.3 | 1.1 | n.i | 2.3 | 2.3 | ||||
| 2 | REG | 4.80 (± 0.00) | 17.98 (± 0.55) | 78.1 | 2.59 (± 0.75) | 73.4 | 20.13 (± 0.01) | 49.6 | 3.1 | 1.0 | 4.5 | n.i | n.i |
| LF | 0.0967 (± 0.0003) | 62.34 (± 1.77) | 0.82 (± 0.75) | 9.68 (± 0.04) | 3.2 | 1.0 | n.i | 2.5 | 2.5 | ||||
| 3 | REG | 4.63 (± 0.01) | 13.56 (± 0.50) | 57.7 | 1.75 (± 0.77) | 9.0 | 55.72 (± 3.10) | 90.1 | 3.2 | 0.8 | 5.0 | n.i | n.i |
| LF | 0.1174 (± 0.0002) | 32.23 (± 0.86) | 1.99 (± 0.84) | 12.36 (± 0.80) | 3.2 | 0.8 | n.i | 2.3 | 2.4 | ||||
| 4 | REG | 4.70 (± 0.02) | 12.61 (± 0.50) | 85.0 | 3.13 (± 0.76) | 2.8 | 36.44 (± 0.16) | 42.3 | 3.0 | 1.0 | 5.0 | n.i | n.i |
| LF | 0.1065 (± 0.0004) | 50.60 (± 1.40) | 3.26 (± 0.75) | 19.65 (± 0.22) | 3.0 | 1.0 | n.i | 2.5 | 2.5 | ||||
| 5 | REG | 4.71 (± 0.00) | 9.24 (± 0.49) | 78.6 | 3.55 (± 0.79) | 1.1 | 19.42 (± 0.13) | n.q | 3.3 | 1.1 | 4.7 | n.i | n.i |
| LF | 0.0964 (± 0.0002) | 32.38 (± 0.86) | 3.61 (± 0.79) | n.q | 3.3 | 1.1 | n.i | 2.4 | 2.3 | ||||
| 6 | REG | 4.80 (± 0.01) | 13.41 (± 0.50) | 55.4 | 2.57 (± 0.77) | 7.6 | 47.73 (± 0.97) | 90.7 | 3.2 | 1.3 | 4.6 | n.i | n.i |
| LF | 0.1071 (± 0.0001) | 30.67 (± 0.82) | 2.31 (± 0.78) | 10.42 (± 0.21) | 3.2 | 1.4 | n.i | n.i | n.i | ||||
| Global valuesd | REG | 4.74 (± 0.07) | 13.11 (± 2.86) | 74.3 | 2.98 (± 0.88) | 4.0 | 35.59 (± 14.53) | 65.6 | 3.18 (± 0.12) | 1.05 (± 0.16) | 4.75 (± 0.21) | – | – |
| LF | 0.1070 (± 0.0094) | 42.15 (± 12.74) | 2.82 (± 1.43) | 13.03 (± 4.56) | 3.20 (± 0.11) | 1.07 (± 0.20) | – | 2.38 (± 0.11) | 2.42 (± 0.08) | ||||
| Matrix effecte | n.a | 6.44* | 0.47* | 3.41** | n.a | ||||||||
% CVintra coefficient of variation calculated intra-brand, considering both REG and LF samples from the same brand, n.q. not quantified, n.a. not applicable, n.i. not informed
*tcritical = 2.57 (n = 6, α = 0.05)
**tcritical = 3.18 (n = 4, α = 0.05)
aDairy matrix classification according to the lactose content, where REG: regular milk, and LF: lactose-free milk, and nutritional composition as reported on the product’s label
bStandard deviation in parentheses for authentic duplicates (n = 2)
cConfidence interval calculated based on model parameters
dGlobal means considering all replicates, standard deviation in parentheses (n = 6)
ePaired t test considering REG and LF thermal indicators