2.1. Production and Characterization of GS-OSCs from Garlic at a Low Temperature
Heating during extraction, storage at high temperature and/or extreme pHs can adversely affect the
quality of garlic OSCs [26–31]. In order to reduce the garlic OSCs’ oxidative and degradation
processes that usually occur during the extraction protocols performed at high temperatures, in this
study, the preparation of garlic extracts at low temperatures and physiologic pH has been optimized.
The water-soluble garlic extracts were, thus, obtained using two different protocols of preparation: one
incubating the crushed garlic in a bain-marie at 100 °C and the other one freezing and pressing the
crushed garlic at low temperatures obtained using liquid nitrogen. Extracted solutions were then
filtered and analyzed by RP-HPLC (Figure 1) and NMR spectroscopy (see Supplementary Material
Figure S1). The RP-HPLC analysis of extracts performed at low temperatures showed a better
resolution of the elution peaks, very likely due to a minor OSC oxidation in the extraction phase,
which is consistent with the presence of a few oxidized forms with limited hydrophobic differences.
Moreover, considering the high concentration of GSH in eukaryotic cells, its effects on the formation
of bioactive OSCs from allicin was evaluated. The chromatograms of the both water-soluble fractions,
which were extracted in the presence of GSH, showed more hydrophilic peaks that were eluted at