*3.8. Betalain Content*

Betalain content of beetroot parts extracts were estimated spectrophotometrically as described by Anand et al. and Castellanos-Santiago and Yahia [46,47]. Betacyanin and betaxanthin content were measured in the extracts at 535 and 483 nm, respectively by using (Jenway 6405UV/VIS) spectrophotometer. Betalain content was calculated as mg/g by the following Equations (3) and (4):

$$\text{Betayanin / Betaxanthi} \ (\text{mg/g}) \ = \frac{\text{A} \times \text{DF} \times \text{MW} \times \text{V}}{\varepsilon \text{LW}} \tag{3}$$

where: A is the maximum recorded absorption for betacyanins and betaxanthins, respectively, DF is the dilution factor, V is the extract volume (mL), W is the dried sample weight (g), and L is the path-length (1 cm) of the cuvette. The molecular weight and molar extinction coefficient (ε) of betacyanin are 550 g/mol, 60,000 L/(mol cm) in water, and of betaxanthin are 308 g/mol, 48,000 L/(mol cm) in water, respectively.

$$\text{Betaian content } \text{mg/g} = \text{betacyanin } (\text{mg/g}) + \text{betaxantiin } (\text{mg/g}) \tag{4}$$
