3.6.4. Firmness

The firmness of non-packaged and film-packaged strawberries was measured at 18 ± 2 ◦C using a texture analyzer with a 5 kg load cell. A single, whole strawberry was placed on a floating platform and a 2 mm diameter flat head stainless steel cylindrical probe was set to penetrate 6 mm into the fruit at 1 mm/s [43]. After the firmness measurements, the strawberries were cut into small pieces and homogenized for 2 min at high speed using a hand-held blender. The homogenized strawberry puree was divided into three groups of 5 g, 5 g, and 10 g.

#### 3.6.5. Titratable Acidity (TA)

For the TA analyses, 5 g of the homogenized strawberry puree was put into 50 mL volumetric flask with the distilled water constant volume for 30 min and then filtered. Taking 20 mL filtrate titrated using 0.01 mol/L NaOH. The total titratable acidity of the diluted puree was calculated using the formula:

$$\text{TA} = (V(\text{NaOH}) \times 0.1 \times 0.064 \times V\_0) / (m \times V\_1) \tag{2}$$

*V*(NaOH) is the mL of NaOH spent for titration, 0.1 is the molarity of NaOH solution, 0.064 is conversion factor for citric acid; *V*<sup>0</sup> is the volumetric of the volumetric flask; m is filtrate volume. The results were expressed as percent citric acid (g citric acid/100 g dry weight). For determining soluble solids content (SSC), 5 g of homogenized strawberry puree was suspended in 10 mL distilled water and then filtered by filter paper.
