## 3 Results and Discussion
[43] noted a 6.5-fold increase in the antioxidant activity of fermented black garlic cloves and a 9.5-fold increase in this parameter for fermented garlic heads. Additionally, they showed that the antioxidant activity of garlic increases with the increasing process temperature, peaking at 72 \({}^{\circ}\)C. A similar relationship was also shown by [PERSON] et al. [36]. During the heat treatment of black garlic at 80 \({}^{\circ}\)C, they noted a more than sevenfold increase in the DPPH radical scavenging ability, and at 40 \({}^{\circ}\)C--by half as much (3.6-fold), which would confirm the positive relationship between the antioxidant properties of black garlic and heat treatment temperature. Other authors, examining the changes in the antioxidant activity of black garlic over time, have shown that it increases intensively (about twofold) until the 21 st day of fermentation, and then it slightly decreases [40]. The basic substances with antioxidant properties in black garlic, whose content increases many times as a result of fermentation processes, include polyphenol compounds, sulfur compounds being allin and allicin derivatives, i.e., diallyl sulfides, disulfides and trisulfides, and S-allyl-cysteine, whose content may increase even six times, which results in even several dozen times higher antioxidant activity of black garlic [37; 41]. S-allyl-cysteine is produced by the enzymatic hydrolysis of \(\gamma\)-glutamyl-S-allycysteine (GSAC) present in significant amounts in raw garlic (GSAC) under the influence of the temperature-dependent \(\gamma\)-glutamyl transpeptidase (\(\gamma\)-GTP) [84; 32; 40; 85]. The activity of \(\gamma\)-GTP is also enhanced by the high water content in fermented garlic [36; 38; 50]; therefore, the fermentation conditions present during the aging of garlic, mainly temperature and humidity, determine the amount and share of individual organosulfur metabolites to a wide extent, and thus also the antioxidant properties of the final product obtained. The increase in the total antioxidant activity in black garlic is explained in the literature not only by an increase in the content of total polyphenols or S-allyl-cysteine [82], but also by the content of browning products formed in Maillard reactions during the aging of garlic, also responsible for the color of black garlic [46; 47; 86; 87; 88]. Similarities and differences found in the tested quality parameters in tested garlic samples are shown in Figure 2. This projection shows the distribution of the results on the plane formed by the selected two factors which were responsible for the variability of the samples in 86.80% (factor p1 and p2). In other words, the projection is a correlation image of the obtained data. The location of the garlic samples in a coordinate system built using two main components shows that they were characterized by large diversity of evaluated parameters. It was found that the tested garlic samples were divided into three groups: the BG and BGEcol samples (first group), the GR sample (second group) and the GREcol sample (third group), which means that they were characterized by a diversity of the evaluated parameters (in the projection, the sample groups were located far away from each other). In the case of BG and BGEcol, the results were very similar in respect of total flavonoids, total phenolic acids, total polyphenol content, quercetin, kaempfer, chlorogenic acid and caffe acid. These samples were different from the GREcol and GR samples in terms of p-coumaric acid, catechin, gallate epigallocatechin and moisture content. At the same time, the GR sample had a higher content of gallic acid, ferulic acid, myricetin, epicatechin and higher aw and pH values than BG, BGEcol and GREcol samples.