*2.6. Porosity*

True density (ρ) and apparent density (ρa) were obtained in order to obtain the porosity (<sup>ε</sup>, %). True density was calculated based on the sample composition (Equation (4)). Portions of the cakes were obtained with a punch of 22 mm diameter, and were exactly measured in height and diameter with a calliper. Apparent density of each portion was calculated from the weight (m, g; XS204 DeltaRange®, Mettler Toledo, Switzerland) and corresponding volume (V, cm3) (Equation (5)). The porosity was calculated from Equation (6).

$$\rho = \frac{1}{\frac{\chi\_{\rm w}}{\rho\_{\rm w}} + \frac{\chi\_{\rm GH}}{\rho\_{\rm GH}}} \tag{4}$$

where xw and xCH are the mass fractions of the two main components of each sample (water and carbohydrates, respectively, xw was determined as described in Section 2.3, and xCH by difference); ρw and ρCH are their densities (ρCH = 1.4246 g/cm3, ρw = 0.9976 g/cm<sup>3</sup> [30]).

$$
\rho\_{\mathbf{a}} = \frac{\mathbf{m}}{\mathbf{v}}\tag{5}
$$

$$
\varepsilon(\%) = 100 \frac{\rho - \rho\_{\rm a}}{\rho} \tag{6}
$$

#### *2.7. Total Polyphenolic Compounds*

The extraction of total phenolic compunds (TP) was carried out according to Tomás-Barberán et al. [31] with minor modifications. FOP (2.5 g) or freeze-dried puree (0.5 g) were mixed with 9 mL of methanol:water (70:30) using a magnetic multi-stirrer at 200 rpm (JEIO TECH Lab Companion MS-51M, JEIO TECH Lab Companion, Seoul, Korea) under darkness and at room temperature for 30 min. The homogenates were centrifuged at 11,515× *g* at 4 ◦C for 10 min (GYROZEN Co., 1236R, GYROZEN, Daejeon, Korea). The supernatant was collected and analysed as to TP using the Folin–Ciocalteu method, which was adapted from Benzie et al. [32] with some modifications as described by Selvendran et al. [33]. The TP content was calculated as mg of gallic acid equivalents (GAE)/100 g dry basis (db) sample, using a standard curve in the range of 0–1000 ppm of gallic acid (Sigma-Aldrich, Saint Louis, MO, USA). In this study, all bioactive compounds were referred to the

percentage (%) of the corresponding bioactive compound preserved in the freeze-dried puree (FDP) in reference to the FOP, calculated based on Equation (7). This test was done in triplicate for each sample.

$$\text{PBc } \text{(\%)} \;= \,\frac{\text{Bc}\_{\text{FDP}}}{\text{Bc}\_{\text{FOP}}} \times 100\tag{7}$$

where PBc (%) is the percentage of the corresponding bioactive compound preserved; BcFDP is the bioactive compound content in the freeze-dried puree (mg/100 db); and BcFOP is the bioactive compound content in the formulated orange puree (mg/100 g db).
