A Comparison of the Antimicrobial Activity, Antioxidant Activity, and Allicin Content between White Garlic and Black Garlic

Yap, Pui Ying (2023) A Comparison of the Antimicrobial Activity, Antioxidant Activity, and Allicin Content between White Garlic and Black Garlic. Final Year Project (Bachelor), Tunku Abdul Rahman University College.

Text Yap Pui Ying_Full Text.pdf Restricted to Registered users only Download (1MB)

Abstract

Food spoilage is a leading cause of food waste and food safety, with significant negative impacts on the global economy and health. Due to consumer preference, the food industry is increasingly interested in using natural preservatives such as garlic to reduce foodborne illness and food spoilage, rather than chemical preservatives. The main purpose of this research is to investigate the effect of ageing on the preservative potential of garlic. This was done by comparing the antimicrobial activity, antioxidant activity, total phenolic content, total flavonoid content, and allicin content between white garlic and black garlic (aged garlic). The antimicrobial activity against S. aureus, L. monocytogenes, P. aeruginosa, and S. enterica was evaluated via disk diffusion test and MIC test. DPPH free radical scavenging activity and FRAP assay were used for the antioxidant activity analysis. The total phenolic content, total flavonoid content, and allicin content were determined by the Folin-Ciocalteu assay, aluminium chloride assay, and UV-Vis spectrophotometric method, respectively. Results indicated that phenolic content and flavonoid content had a direct relationship with the antioxidant activity of garlic. There was a significant difference (p-value < 0.05) between white garlic and black garlic. Black garlic showed the highest antioxidant activity and antimicrobial activity, with larger inhibition, lower MIC results, higher DPPH free radical scavenging activity (42.92 ± 0.21 mg AAE/100 g), higher FRAP activity (49.81 ± 0.19 mg FE/100 g), higher total phenolic content (53.69 ± 0.37 mg GAE/100 g), and higher total flavonoid content (67.10 ± 0.82 mg CE/100 g) as compared to white garlic. This is mainly due to the improvement of bioactive compounds during the ageing process. In short, black garlic had a higher preservative potential than white garlic due to its higher antimicrobial and antioxidant activities