*2.8. Surface Carotenoid (SC) and Encapsulated Carotenoids (EC)*

The surface carotenoids (SC) were determined according to Wagner and Warthesen [13] with some adaptations. A total of 20–50 mg (m) of the powder sample were weighed into centrifugal vials and extracted with 10 mL hexane (0.1% *w*/*v* BHT). For the extraction of surface carotenoids, samples with the hexane were shaken for 5 min and subsequently centrifuged (rcf = 2800 g) for two min. The absorbance (A) of the hexane phase was measured spectrophotometrically at λmax with hexane as sample blank. The SC were calculated according Equation (2).

$$\text{SC}\left[\frac{\text{mg}}{\text{g}}\right] = \frac{\text{A} \times 10^2}{\frac{1\% \text{ } \text{E}}{1 \text{ cm}} \times \text{m}}.\tag{2}$$

1% 1 cmE and λmax were equivalent to Equation (1). The amount of encapsulated carotenoids (EC) was defined as the difference of TC to SC.
