Antioxidant and antimicrobial activities of ginger with aging and fermentation

Abstract

Zingiber officinale Roscoe, commonly known as ginger, has long been used as a powerful health-promoting antioxidant that supports cellular health of the human body. The objective of this study was to compare the antioxidant and antimicrobial activities of the samples with aging and fermentation. Antioxidant activities of the samples were compared using total phenol, flavonoid contents, ABTS cation radical scavenging activity and DPPH radical scavenging activity. Antimicrobial activities were also examined using the paper disc method and minimum inhibitory concentration (MIC). Acidity of the fermented ginger (FG) with lactic acid bacteria showed a significantly higher value than that of the ginger (GG). The content of 6-gingerol, a bioactive component in ginger, decreased in all fermented gingers but 6-shogaol which is also one of the main valuable ingredients showed the increased content at ginger fermented with Streptococcus thermophilus and Lactobacillus acidphilus. Flavonoid contents of the FG and GG did not show significant differences. However, ABTS cation radical scavenging activity and DPPH radical scavenging activity were 10-30% increased in the samples with fermentation (p<0.05), respectively. The samples of the disc showed an inhibitory effect on growth of gram positive Staphylococcus aureus and Listeria monocytogenes. Zinger with fermentation showed higher antioxidant and antimicrobial activities. Thus, we conclude that aging and fermentation can be a helpful process to increase the functional effects of ginger.