## 3 Results
### Amino Acids Composition  
Table 2 shows the results of the determination of amino acids, including essential amino acids, of all protein preparations. According to FAO/WHO/UNU [40], the amino acid composition pattern for essential amino acids is also presented.  
In most cases, the amino acid composition of the tested protein preparations meets the requirements set by FAO/WHO/UNU [40]. However, there are cases where the amount of amino acids in the tested protein preparations is lower than in the standard. In the case of threonine, the highest amounts were recorded in potato protein (64.6 mg), almost twice the standard's value. Next, a lower value, but still relatively high compared to the standard, was determined in the WPC control sample (56.2 mg). The other preparations had values close to each other (27.7-33.5 mg) but still amounts above those in the standard (23 mg). Cysteine levels were higher than the standard in all cases, with rice protein (23.1 mg) and WPC80 (27.9 mg) having the highest content of this amino acid. However, comparing the other protein sources to the control WPC80, only rice protein has a similar amount of cysteine. Valine levels are also close to the pattern, slightly exceeding the standard value (39 mg). Only in _Arthrospira_ is the valine level lower, but just by 3.6 mg. Methionine content in all samples is above the reference protein; in most cases, the amount of methionine is close to that in WPC80. Only edible insect powder does not exceed the recommended isoleucine content, but the difference is just 0.8 mg. Other samples contain more isoleucine than the recommended standard. Leucine is at a similar, slightly lower level than the standard in the insect protein, _Arthrospira_, and SCP samples, while potato protein, rice protein, and WPC80 contain significantly more leucine than the others and exceed the values in the standard. The reason is most likely that the overall protein content of edible insects, algae, and SCP is lower than that of rice protein, potato protein, and WPC80. The total lower protein content translated into a lower content of individual amino acids. To maximize the amino acid content per 100 g, it would be necessary to obtain protein isolates from these preparations. The recommended content for phenylalanine was exceeded only in potato protein and rice protein. The remaining sources contain less than the recommended value (30 mg) but still at a reasonable level above 25 mg. The histidine level in the algae preparation is below the recommended content by 4.8 mg. Moreover, in the case of lysine, algae protein contains the lowest amount of this amino acid, much below the general pattern (27.8 vs. 45 mg). In this case, the rice protein also falls short of the benchmark (30.1 mg) and the insect protein slightly below the recommendation (41.2 mg). Tryptophan content significantly exceeds the recommended amounts for all samples tested. The sum of all essential amino acids in all samples tested is above the reference value. The highest amounts of essential amino acids were determined in the potato protein (478.31 mg), while the least in the algae preparation (272.63 mg). Although the amino acid content varies from one formulation to another, and not all essential amino acids meet the reference standard, it can be crucial to use the right amount of formulation per serving of the whole product. In the study by [PERSON] et al. (2013), supplementation with 48 g of WPC80 or rice protein was shown to be just as effective in athletes [41]. In addition, individual proteins can be fermented, which can increase their digestibility and bioavailability [12].