[6-1130-P] Functional/Wellness Foods & Nutrition (6th)

[6-1130-P-04] Investigation of some biological activities of local shallot (Allium ascalonicum Linn.) extract from Thailand

*Premruethai Phansaard¹, Pairote Wongputtisin¹ (1. Program in Biotechnology, Faculty of Science, Maejo University, Chiang Mai, Thailand(Thailand))

Keywords:shallot extract, prebiotic, antioxidant activity, antibacterial activity, functional food

Shallot (Allium ascalonicum Linn.) is a good source of several nutrients and phytochemicals. Shallot-based functional foods have been being developed in our research group. The partial purified shallot extract was prepared according to the processes developed in our group for utilizing as functional food ingredient of many food products. The aims of this present work were then to investigate some biological activities including antibacterial activity and antioxidant activity of shallot extract prepared from local cultivar of Srisaket province, Thailand. The results showed that both crude and partial purified extracts were rich in oligosaccharides and polysaccharides, with degree of polymerization (DP) about 23-283. Interestingly, it was found that purification processes used in this study, based on adsorption method, removed some low molecular weight sugars from shallot extract. ABTS radical scavenging assay was used in antioxidant activity test of the extracts. The crude extract exhibited significantly higher ABTS scavenging activity than the purified extract. The results also revealed that ABTS scavenging activity continuously decreased according to number of purification step. The similar results were found in antibacterial test that shallot extract lost the activity after purification processes. However, crude extract could inhibit growth of pathogenic Salmonella Typhimurium and Staphylococcus aureus but not for Escherichia coli in agar diffusion assay. Moreover, the minimum inhibitory concentration (MIC) values of crude extract on S. Typhimurium and S. aureus were 114.66 and 163.80 mg/ml, respectively, and only S. Typhimurium was disinfected by crude extract with the minimum bactericidal concentration (MBC) value at 147.42 mg/ml. It could be concluded that shallot extract possess high potential to be applied in functional food manufacturing. However, crude extract and purified extract might be suitable for different purposes, including prebiotic, antioxidant and antibacterial uses.