## 4 Discussion  
Knowledge of the chemical composition plays an important role in determining the nutritional value of bee pollen, especially for human use. The physico-chemical properties of bee pollen can be affected by processing techniques [44; 45], as well as storage conditions [46], but the overall quality of bee pollen primarily depends on biological factors. Freshly collected bee pollen may contain 10% to 30% moisture [4; 12; 47; 48; 49; 50], which is in agreement with the data obtained in this study, where the moisture content ranged from 11.30% to 26.48%. The fresh bee pollen has more important nutritional value for human use compared to dried bee pollen, which contains less than 8% of moisture [4]. However, the high content of moisture in fresh bee pollen makes it an ideal culture for different microorganisms, particularly yeasts and molds, and to preserve the good quality of bee pollen, it should be harvested daily from pollen traps and stored in deep freezer under \(-18\)\({}^{\circ}\)C until consumption. Ash (minerals) is important for nutritional value of bee pollen, but its content can be largely affected by climate, geographical and botanical origin. However, soil type has the main influence on the mineral content of bee pollen [51; 52]. In average, bee pollen contains 0.5-6.5% of ash [4; 26; 48; 50; 53; 54; 55; 56; 57]. The results obtained in the present study are in compliance with above mentioned studies, as the ash content ranged from 1.15% to 3.81%. The mineral composition is stable, and it does not change significantly in the drying process of bee pollen, as reported by [PERSON] et al. [44] and [PERSON] et al. [45]. Numerous studies have covered investigation of various physico-chemical parameters of multiforal bee pollen, including protein content [4; 12; 49; 52]. Although multiforal bee pollen contains pollen grains of different plant species, its total protein content is on average not always significantly higher compared to unifloral bee pollen. The results presented in this study confirmed this; the unifloral bee pollen from _Prunus_ species, _P. tanacetifolia_ and _A. hippocastanum_ contained a higher protein content compared to other investigated unifloral and multiforal bee pollen samples. The protein content showed significant variations among the pollen samples ranging from 14.23% to 23.29% in the multiforal bee pollen, and from 14.02% in _T. officinal_ bee pollen to 27.26% in _A. hippocastanum_ bee pollen. The obtained data are in agreement with the results reported by [PERSON] et al. [26], [PERSON]  
Figure 3: Comparative spectral features of bee pollen with regard to pigmentation (FTIR-ATR spectra of dark colored _P. rhoas_ vs. light colored _Viburnum_ spp. bee pollen). et al. [56], [PERSON] et al. [57], [PERSON] et al. [58], and [PERSON] et al. [59], higher than those obtained by [PERSON] [60], and lower compared to reports provided by [PERSON] et al. [50], [PERSON] et al. [61], and [PERSON] et al. [62]. Glucose, fructose and sucrose were the major components in investigated bee pollen samples, and they showed great variations, especially among unifloral bee pollen samples. As presented in Table 2, fructose ranged from 10.79% to 23.88%, glucose from 8.92% to 18.70% and sucrose from only 2.62% to 22.04% in multifocal bee pollen samples. These values are in compliance with findings reported [PERSON] et al. [63], [PERSON] et al. [64], [PERSON] et al. [65], and [PERSON] et al. [66]. In unifloral samples fructose ranged from 10.87% in _T. officinal_ bee pollen to 25.65% in _A. hippocastanum_ bee pollen, glucose from 8.96% also in _A. hippocastanum_ bee pollen to 19.86% in _Q. pubscens_ bee pollen, and sucrose from 1.62% in _T. officinal_ bee pollen to 20.33% in _P. spinosa_ bee pollen. Comparing obtained values to the ones of some unifloral bee pollen samples from available literature, such as _T. officinal_ and _Prunus_ spp. from Romania [12], _Salix_ spp. from Serbia [56], _P. tanacetifolia_ and _Salix_ spp. from Slovenia [66; 67], and _T. officinal_ and _Salix_ spp.