Table 4.
Degradation coefficients k of lutein (Lut) and zeaxanthin (Zx) in the different formulations over 30 d of storage at 40 °C.
| Sample | Lut (%/d) |
Zx (%/d) |
||||||
|---|---|---|---|---|---|---|---|---|
| pH 2.5 | pH 5.5 | pH 7.5 | pH 9.5 | pH 2.5 | pH 5.5 | pH 7.5 | pH 9.5 | |
| Blank | 1.45 | 1.45 | 1.18 | 1.15 | 1.30 | 1.11 | 0.95 | 0.99 |
| Control | 2.75 | 2.39 | 2.19 | 1.51 | 2.34 | 2.18 | 2.00 | 1.58 |
| Complex | 1.90 | 1.52 | 1.29 | 1.13 | 1.55 | 1.40 | 1.13 | 1.03 |
| Δka | 0.85 | 0.87 | 0.9 | 0.38 | 0.79 | 0.78 | 0.87 | 0.55 |
a
Δk is the difference between the degradation coefficients of the control and complex samples, and it represents the improvement in the chemical stability of Lut/Zx via complexation with WPI.