*2.11. Titratable Acidity*

Titratable acidity (TA) was measured using the Association of Official Analytical Chemists (AOAC) titrimetric method for fruits [23] by titrating 10 mL of strawberry juice with 0.1 mol/L NaOH using phenolphthalein as an indicator. The tests were done in triplicate on coated and uncoated samples. The results are expressed in citric acid (%).

$$\text{Titratable acidity} \left( \% \right) = \frac{\text{V} (\text{NaOH}) (0.1) (0.064)}{\text{m}} \times 100 \tag{1}$$

where V(NaOH) is the mL of NaOH used during titration; (0.1) is the molarity of the NaOH solution used; (0.064) is the conversion factor for citric acid, which is the main acid in strawberries; and (m) is the mass of the strawberry samples used during the test [24].
