## 1 Introduction
Thus, we applied a method that consisted of drying, grinding, and sieving to concentrate the bioactive compounds in some granulometric classes of blackthorn berry powders [21; 22; 23]. The powders from the fruits of wild plants have an advantage over traditional bioactive compounds extracted from fruits using solvent extraction because this method preserves the bioactive ingredients, particularly their bioactivity, for human consumption [24]. The process of grinding results in a decrease in particle size, a widening of the dispersion of particle sizes, and an increase in the specific surface area, all of which enhance the functional properties of the material [21]. Given that one of the key factors influencing extraction is particle size, this can create confusion regarding the extraction of bioactive compounds that can occur either following the extraction processes or from the sample grinding stage [25]. Fruit powders are separated by granulometric differentiation using decreasing mesh sieves during the sieving process, which results in the controlled distribution of bioactive compounds in the various granulometric fractions [24]. The relationship between variety of particle sizes in plant powders, the bioactive ingredient amounts, the physicochemical characteristics, and antioxidant activity has been documented in several recent research studies [21; 22; 23; 24]. From an industrial perspective, the functional qualities of powders, such as their flowability, preservation potential, and functional properties are crucial because they dictate how they should be produced, handled, stored, and reconstituted to preserve their bioactive components. The particle size and physical structure can have a significant influence on the physicochemical properties of powders [26; 27; 28]. Although the blackthorn fruits have been examined in the specialized literature, there are still only a few references addressing the detailed composition and fraction of the crushed products in terms of chemical composition and biological activity [1; 2; 3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17]. There are a number of articles on the extraction of bioactive compounds and those with antioxidant activity from blackthorn berry fruits, focusing on extraction with solvents of different polarity, or with eutectic solvents using techniques such as ultrasound (US), pulsed electric field (PEF), and the simplex lattice mixture design method [5; 29; 30; 31]. Increased understanding of the impact of particle size on the phytochemical characteristics, powder functional properties, and preservation ability of powdered blackthorn berries was the goal of the current study. There are also research studies [32; 33; 34; 35] showing that the particle size distribution provides a complete description of a powder, and sieving is the operation that can produce a sample with a uniform particle size distribution, facilitating the development of products with improved functional properties. This study aimed to evaluate the characteristics of the blackthorn berry ground powder with different particle sizes, such as several relevant chemical and powder functional properties, as well as the main parameters reflecting powder quality suitability for storage purposes. This research is intended to expand our understanding of the importance of grinding and sieving in order to obtain vegetal powders with specific characteristics that could be used as valuable ingredients to develop functional foods.