*2.1. Materials*

The experiments were carried out with fresh blueberries of the Huertos de Chile brand (variety *Vaccinium corymbosum*), which were bought at a local market. Blueberries with a diameter of 14–15 mm were selected.

#### *2.2. Blueberry Characterization and Freezing*

The blueberry fruits used as raw material to carry out a set of experimental treatments were characterized to ensure a homogeneous quality of said material. Total Soluble Solids (TSS), or ◦Brix, was selected for this purpose as it is one of the main quality indicators of the blueberry fruit [29]. To determine ◦Brix, blueberry fruits were weighed using a RADWAG balance (AS 220/C/2, Radom, Poland) and then crushed and homogenized for 5 min with 10 mL of distilled water until a homogeneous juice was obtained. The resulting juice was filtered, and aliquots were taken for ◦Brix analysis with a HI 96,680 digital refractometer (Hanna instruments, Rothe Island, USA).

Blueberries to be used in the set of experimental treatments were first frozen in a convection freezer (MT05, Alaska, Minas Gerias city, Brasil) at −40 ◦C for 2 h to obtain a product temperature equal to or less than −35 ◦C.

A series of experiments, divided into two steps, was carried out in order to achieve the research objectives:

	- a. Whole, without any treatment.
	- b. Cut in half.
	- c. With 1, 3, 6, and 9 CO2-laser microperforations.

The Pressure Increase Test (PIT) was performed to estimate the treatment effect on primary drying time, and the MTM method was applied to evaluate the mass transfer phenomena, as affected by blueberry characteristics (skin, A, RT) and the busting process. The final fraction of busted blueberries was also evaluated. Table 1 depicts a summary of the experimental setup, showing its two steps—visual observation/evaluation of the busting process of whole blueberries and a total of 6 treatments to evaluate the effect of CO2-laser microperforations on primary drying time and quality.

> **Table 1.** Description of the experimental setup.

