Antioxidant potential and antimicrobial efficacy of seaweed (Himanthalia elongata) extract in model food systems

Extracts from marine sources exhibit antimicrobial and antioxidant properties in vitro and there has been great interest within the food industry to move towards natural methods of food preservation. Natural extracts from seaweeds could potentially have a multiple functionality within the food industry to increase safety and enhance the quality of food products. The present study is aimed to assess the antimicrobial activity of a hydrophilic extract from the fucoid brown alga Himanthalia elongata in model food systems. Carbohydrate and protein model food systems (CMFS and PMFS, respectively) were studied at varying concentrations (1 %, 5 % and 10 %) and bacterial inhibition of the extract was investigated against Salmonella abony and Listeria monocytogenes. The extract provided up to 100 % inhibition of the bacteria with a bactericidal effect in CMFS, while a bacteriostatic effect was seen in PMFS. In general, there was a significant difference (P < 0.05) between the efficacies of the extract against S. abony as compared to L. monocytogenes with higher inhibition for S. abony. In terms of antioxidants; the extract had a total phenolic content of 34.0 mg GAE g(-1) of extract and a DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity of 139.8 mg AAE g of extract. The results of the present study are promising as it provides an insight for the inclusion of seaweed extracts into real food systems.