This study investigates the effects of different temperature conditions on the quality of black garlic (BG) during the aging process. Two temperature protocols were employed: gradual heating and cooling (GHC), where the temperature was slowly raised from 45 °C to 77 °C and then lowered to 59 °C at a rate of 1 °C per hour, and rapid heating and cooling (RHC), where the temperature was quickly raised from 45 °C to 85 °C and then lowered to 56 °C at a rate of 1 °C every 30 min. Changes in surface color, hardness, moisture, pH, fructose, total polyphenol content (TPC), and key sulfur compounds such as alliin, S-allylcysteine (SAC), and γ-glutamyl-S-allylcysteine (γ-GSAC) were analyzed. Our findings showed that GHC led to a higher increase in TPC and fructose content by the 15th day compared to RHC. In contrast, RHC retained significantly higher SAC concentrations, approximately 1.7 times that of GHC, by the end of the aging period. Surface color changes, particularly in lightness and redness, were more pronounced under GHC, while RHC demonstrated superior moisture retention. These findings indicate that GHC is better suited for products prioritizing polyphenols and sugars, while RHC is more optimal for SAC-enriched BG. This study provides valuable insights into optimizing BG production for diverse food and medicinal applications through precise temperature modulation.

Many biological functions of curcumin have been reported. As certain bioactivities of curcumin are eliminated by antioxidants, reactive oxygen species generated by curcumin have been suggested as a relevant mechanism. In the present study, the effects of different types of antioxidants on the stability and bioactivities of curcumin were analyzed. High concentrations (>4 mM) of thiol antioxidants, including N-acetylcysteine (NAC), glutathione (GSH), and β-mercaptoethanol, accelerated the decomposition of curcumin and other curcuminoids; the submillimolar levels (<0.5 mM) of GSH and NAC rather improved their stability. Ascorbic acid or superoxide dismutase also stabilized curcumin, regardless of their concentration. The cellular levels and bioactivities of curcumin, including its cytotoxicity and the induction of heme oxygenase-1, were significantly reduced in the presence of 8 mM of GSH and NAC. The effects were enhanced in the presence of submillilmolar GSH and NAC, or non-thiol antioxidants. The present results indicate that antioxidants with a reduced thiol group could directly interact with the α,β-unsaturated carbonyl moiety of curcuminoids and modulate their stability and bioactivity.

Ionizing radiation is a well-known environmental stressor capable of generating excessive reactive oxygen species (ROS), leading to oxidative damage in sensitive tissues, including the reproductive system. While oxidative stress is increasingly implicated in male reproductive dysfunction, the long-term effects of low-dose-rate (LDR) radiation on testicular structure and oxidative status remain underexplored. In this study, mice were exposed to continuous LDR radiation (0.39, 1.29, and 3.46 mGy/h) for 21 days to assess testicular histopathology and oxidative status. Although testis weight did not significantly differ among groups, histological analysis revealed basal membrane disruption and reduced spermatogenic cell populations in irradiated groups. Masson’s Trichrome and Sirius Red staining demonstrated dose-dependent collagen deposition, indicating progressive testicular fibrosis. TUNEL assays confirmed increased germ cell apoptosis in the mid- and high-dose-rate groups. ROS levels were significantly elevated only in the highest-dose group, suggesting a threshold-dependent oxidative stress response. These findings indicate that chronic LDR radiation induces testicular damage primarily through apoptosis and fibrosis, with oxidative stress potentially contributing at higher exposure levels.

Many biological functions of curcumin have been reported. As certain bioactivities of curcumin are eliminated by antioxidants, reactive oxygen species generated by curcumin have been suggested as a relevant mechanism. In the present study, effects of different types of antioxidants on stability and bioactivities of curcumin were analyzed. High concentrations (>4mM) of the thiol antioxidants including N-acetylcysteine (NAC), glutathione (GSH) and β-mercaptoethanol accelerated decomposition of curcumin and other curcuminoids; Submillimolar levels (<0.5 mM) of GSH and NAC rather improved their stability. Ascorbic acid or superoxide dismutase also stabilized curcumin regardless of their concentration. Cellular levels and bioactivities of curcumin including cytotoxicity and induction of heme oxygenase-1 were significantly reduced in the presence of 8 mM of GSH and NAC. The effects were enhanced in the presence of submillilmolar GSH and NAC, or non-thiol antioxidants. The present results indicate that antioxidants with reduced thiol group could directly interact with α, β-unsaturated carbonyl moiety of curcuminoids and modulate their stability and bioactivity.

Spaceflight exposes astronauts to multiple environmental stressors that promote oxidative stress, including ionizing radiation, microgravity, circadian rhythm disruption, and psychological stress. These factors increase the production of reactive oxygen species (ROS) and disturb redox homeostasis, potentially affecting multiple physiological systems during long-duration missions. In addition to environmental challenges, nutritional factors may further influence oxidative balance in space. Space food systems rely on long-term storage and processing, which can lead to degradation of antioxidant nutrients and alterations in dietary composition. Furthermore, spaceflight conditions may modify eating behaviors and disrupt gut microbiome composition, both of which are closely linked to host redox regulation. This review examines current knowledge on oxidative stress during spaceflight and discusses how space food systems, dietary composition, and microbiome alterations interact with spaceflight stressors to influence redox homeostasis. Potential strategies to mitigate oxidative stress are also discussed, including preservation of antioxidant nutrients, optimization of dietary composition, reduction in pro-oxidant exposures, and microbiome-targeted approaches to support astronaut health during long-duration missions.

Ionizing radiation is a potent environmental stressor capable of generating excessive reactive oxygen species (ROS), leading to oxidative damage in various tissues, including reproductive organs. Despite growing awareness of oxidative stress in reproductive failure, the long-term effects of low-dose-rate (LDR) radiation on testicular function and redox imbalance remain underexplored. This study investigated the effect of prolonged LDR radiation exposure (0.39, 1.29, and 3.46 mGy/h) on mice's testicular histology and oxidative status. Although no significant differences in testis weight were observed, histological analysis revealed basal membrane disruption and reduced spermatogenic cell populations in irradiated groups. Masson's Trichrome and Sirius Red staining demonstrated dose-dependent collagen accumulation, indicating progressive testicular fibrosis. TUNEL assays confirmed increased germ cell apoptosis, while oxidative stress levels were significantly increased in the highest dose group (3.46 mGy/h). Our findings suggest that chronic LDR radiation induces testicular injury through ROS overproduction, triggering apoptosis and extracellular matrix remodeling.