## 3 Results and Discussion
### Physical Properties  
The water absorption capacity (WAC) of flours measures the water absorption ability by the starch after swelling in excess water. The results showed that WAC for quinoa flours fractions ranged between 2.50 and 2.92% (Table 2). The results were in accordance with the reported values by [PERSON] et al. (2016) [26] and [PERSON] et al. (2012) [62]. The least WAC was observed for large particle (QL), and all three particle sizes presented significant difference (\(p<0.0001\)) between them, the highest WAC being presented by the medium particle size (QM), making it desirable for use in bakery products. The increase of WAC in QM can be explained by its higher level of protein compared to small particle size (QS), amino acid composition, protein conformation and surface polarity affecting water-binding properties of flours [63]. [PERSON] et al. (2020) [4] reported similar results on three different particle sizes of quinoa flour. WAC may be related to starch characteristics which are reflected by amylose content, granular structure and molecular structure of amylose and amylopectin [64]. Water retention capacity (WRC) allows assessment of the flour's ability to retain water under a centrifugal gravity force, considering physically entrapped, capillary-bound and hydrodynamic water [65]. The results obtained showed that there were no statistically significant differences (\(p>0.05\)) among the large and small particle sizes (Table 2), but significant differences between large and small particle fractions and medium particle size (\(p<0.05\)) were found, which had the maximum WRC (4.91%). The increase of WRC in QM can be related to high protein content and ash, hydration properties being influenced by the particle fraction composition. The results were in range with those found by [PERSON] (2009) [8] for quinoa flour. Approximate results observed between WRC and particle size have been reported in the literature [48] for rye and barley flours. The values were higher than the results reported by [PERSON] et al. (2009) [66], who mentioned that quinoa flours were able to retain 1.47 g of weight of water. The relationship between WRC and the particle size was observed by other authors [67] and can be explained by the large surface area presented by finer flours. Nevertheless, other studies were either not able to establish a correlation between particle size and WRC, or no decrease in WRC was found with reductions in particle size [36]. These differences could be connected to different compositions of particles with different sizes and to the morphology and particle size distribution, which was not evaluated in other studies. The results of the swelling capacity (SC) for each particle fraction are shown in Table 2. The values ranged between 5.26 and 6.21 mL/g. The SC values obtained for the small particles (QS) differed significantly (\(p<0.05\)) from the other two particle sizes, QL and QM, because QS had the highest swelling capacity. These values can be explained by the extent of granular swelling during heating. Quinoa starch granules are approximately 1-3 \(\upmu\)m and the small size of granules facilitates the penetration of water molecules into quinoa starch granules, thereby increasing the SC with particle size decrease. Similar results regarding SC of different quinoa particle size were found by [PERSON] et al. (2015) [68] and [PERSON] et al. (2016) [26]. Knowing the bulk density (BC) is essential when considering packaging and transport. The results of BC values obtained for quinoa flour fractions ranged from 0.46 for the small particle size, 0.52 for medium fraction to 0.55 for the large particle size (Table 2). Significant differences between samples (\(p<0.05\)) were observed, bulk density decreasing with particle size decrease. This trend can be explained, probably, by the negative correlation between bulk density and lipids, and by the positive correlation between bulk density and carbohydrates. Similar findings were obtained by [PERSON] et al. (2019) [69].