Characteristics of fermented vinegar using mulberry and its antioxidant activity

Abstract

This study was carried out to investigate the physicochemical characteristics and antioxidant properties of mulberry juice (MJ) and mulberry vinegar (MV). MV, with acidity of 6.05% and a pH 3.06, was obtained from MJ after 8 days with alcohol fermentation and 20 days with acetic acid fermentation at 30℃. After fermentation, the major sugars in MV were lactose, glucose, and fructose, showing 1,310.06, 293.20, and 41.25 mg%, respectively. The major organic acids in MV were acetic acid (2,725.59 mg%), citric acid (524.66 mg%), and succinic acid (480.63 mg%). The total free amino acid content of MV, such as lysine, arginine, phenylalanine, and tyrosine, was 34.52 mg%. MJ and MV showed radical scavenging activities with respect to 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl (OH), superoxide anion (O 2-), and nitric oxide (NO) radicals in dose-dependent manner, which were closely related to the total polyphenol and flavonoid contents in MJ and MV. In addition, a strong scavenging effect with regards to the OH radical was observed in MJ and MV, an IC 50 value of 0.04 μg/mL. In particular, MV showed a higher O 2 radical scavenging activity than that of MJ. These results suggest that MV can be used as a functional vinegar with antioxidant activity against free radicals.

Mulberry vinegar attenuates lipopolysaccharide and interferon gamma‐induced inflammatory responses in C6 glial cells

“…The C6 glial cells were grown in DMEM supplemented with 10% fetal bovine serum (FBS) and 1% penicillin-streptomycin solution (Welgene Inc., Daegu, Korea). As described in our previous study, the pH value of MV was 3.06 (Bang et al, 2020). The optimum pH levels vary from pH 6.9 to 7.8 depending on cell strain (Ceccarini & Eagle, 1971).…”

“…Another possible anti‐inflammatory effect of active components from MV, such as lysine, could be considered from its inhibition property on the NO and pro‐inflammatory cytokine production (Al‐Malki, 2015). In our preliminary study, the contents of lysine in MV were higher than that of mulberry juice, indicating that lysine contents were increased by alcohol and acetic fermentation (Bang et al, 2020). Although the concentration of polyphenols and flavonoids in vinegar are dependent on the microbial strains used for inoculation in the preparation of MV, these metabolites may contribute to anti‐inflammatory properties against LPS in C6 glial cells.…”

“…Mulberry was obtained from Hadong (South Gyeongsang Province, Korea) and immediately stored at −20°C. MV was produced using a previously described method (Bang et al, 2020). Briefly, the mulberry was sliced and 0.4% of plantase TM (Bision Co., Seoul, Korea) was added to manufacture the mulberry juice (MJ).…”

Fermentation Characteristics of Unripe Citrus unshiu Vinegar Production Using Acetic Acid Bacteria Isolated from Traditional Fermented Vinegars

“…2A ). This decrease in pH is attributed to acetic acid bacteria utilizing alcohol as an energy source and fermentation substrate to produce acetic acid ( Bang et al, 2020 ). The total acidity serves as a vinegar quality indicator as acetic acid bacteria can break down alcohol to produce acetic acid and CO 2 ( Kwon et al, 2014 ; Park et al, 2021 ).…”