Biological Activities of Solid-fermentation Garlic with Lactic Acid Bacteria

Abstract

Garlic (Allium sativum L.) and its extracts have been used in a wide range of applications, including as folk medicines in many Asian countries. This traditional herb has several functional properties and strong biological activities, making it useful as a functional food material. This study investigated the biological activities of solid-garlic after fermentation by lactic acid bacteria. Several solid-garlic fermentation strains of lactic acid bacteria were isolated from Korean traditional fermented food or obtained from the Korean Collection for Type Cultures. Lactic acid bacteria showed selective growth in garlic extracts on MRS media. Fermentation of solid garlic (heated 121℃, 15 min or not heated) by lactic acid bacteria gave total polyphenol and flavonoid contents of 731.0-845.2 g/g and 92.68-413.58 g/g, respectively. The DPPH scavenging activities and SOD like activities were measured as 7,584% and 9499%, respectively. These activities were relatively higher than a positive control, vitamin C. Measurement of antidiabetic activity using α-glucosidase inhibition assay showed that solid garlic fermented with lactic acid bacteria gave a higher activity than the control, acarbose. Fermentation of solid garlic with lactic acid bacteria may therefore help to alleviate adverse biological activities, as well as provide functional food materials.

Effects of different processing methods on the antioxidant and immune stimulating abilities of garlic

“…During fermentation however, proteolytic enzymes from microorganisms hydrolyze complexes of polyphenol into free and soluble phenols which are more active and readily absorbed (Ademiluyi & Oboh, ; Shrestha, Dahal, & Ndungutse, ). Other studies have also reported that LAB release β‐glucosidase which hydrolyze flavonoid‐bound compounds to make flavonoids readily available (Lee, Cho, Kim, & Moon, ; Lee, Joo, & Kwon, ; Yang et al., ). Our results therefore demonstrate that the ability of such bioactive molecules to be released during fermentation is strain dependent.…”

“…The antioxidant effect was evaluated using two widely used methods; DPPH assay and ABTS assay. The DPPH radical has a characteristic absorption at 517 nm in ethanol, which disappears with the acceptance of an electron from antioxidant molecules (Lee, Cho, Kim, & Moon, ; Lee, Joo, & Kwon, ). All the fermented samples showed better DPPH radical scavenging activity than the unfermented samples.…”

“…Nonetheless, the garlic‐derived bioactive compounds contained in these fermented products remain unknown. Also, very few reports are available on the effects of heat drying and subsequent solid‐state fermentation on the biological activities of garlic (Lee, Cho, Kim, & Moon, ; Lee, Joo, & Kwon, ).…”

“…However, the effects of this process on bioactivity of the final product remain unknown. Other studies have shown that fermenting garlic with lactic acid bacteria (LAB) significantly improves its pharmacological effects (Lee, Cho, Kim, & Moon, 2016;Lee, Joo, & Kwon, 2016;Lee, Lee, Yu, Lee, & Cho, 2017). By submerged fermentation, garlic has been fermented with Pediococcus (Ham et al, 2010) and Monascus species (Sumioka, Hayama, Shimokawa, Shiraishi, & Tokunaga, 2006) in an effort to improve its antimicrobial and hypolipidemic activities.…”

“…Nonetheless, the garlic-derived bioactive compounds contained in these fermented products remain unknown. Also, very few reports are available on the effects of heat drying and subsequent solidstate fermentation on the biological activities of garlic (Lee, Cho, Kim, & Moon, 2016;Lee, Joo, & Kwon, 2016). Therefore, in this study, we investigated the effects of freeze drying, heat drying, and solid-state fermentation on the antioxidant and immune stimulating effects of garlic.…”