Antimicrobial and Fermentation Potential of Himanthalia elongata in Food Applications

Abstract

Himanthalia elongata is a brown oceanic seaweed rich in bioactive compounds. It could play an important role in food production because of its antimicrobial and antioxidant properties. Three strains belonging to the Lactobacillus casei group (Lactobacillus casei, Lactobacillus paracasei, and Lactobacillus rhamnosus) and a Bacillus subtilis strain were used for the solid-state fermentation of commercial seaweeds, and bacterial growth was monitored using the plate count method. High-pressure processing (HPP) was also employed (6000 bar, 5 min, 5 °C) before extraction. The antimicrobial activity of the extracts was tested in terms of the main food pathogenic bacteria (Salmonella spp., Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and Bacillus cereus), and the phenolic content was estimated using the Folin–Ciocalteau method. In addition, targeted UHPLC-MS2 methods were used to unravel the profile of phlorotannins. H. elongata allowed the growth of the L. casei group strains and B. subtilis, showing the fermentability of this substrate. Significant antimicrobial activity toward L. monocytogenes was observed in the extracts obtained from unfermented samples, but neither fermentation nor HPP enhanced the natural antimicrobial activity of this seaweed species. The content in the phenolic compounds decreased because of the fermentation process, and the amount of phenolics in both the unfermented and fermented H. elongata extracts was very low. Despite phlorotannins being related to the natural antimicrobial activity of this brown seaweed, these results did not support this association. Even if fermentation and HPP were not proven to be effective tools for enhancing the useful compounds of H. elongata, the seaweed was shown to be a suitable substrate for L. casei group strains as well as for B. subtilis growth, and its extracts exhibited antimicrobial activity toward foodborne pathogens.

Edible Seaweeds and Spirulina Extracts for Food Application: In Vitro and In Situ Evaluation of Antimicrobial Activity towards Foodborne Pathogenic Bacteria

“…In this study three species belonging to Phaeophyceae have been tested. The antimicrobial activity of H. elongata extract has been previously studied with similar results [ 19 , 73 , 74 ], while the extracts obtained in the present work have been more effective against L. monocytogenes and Salmonella spp. than those obtained by Rajauaria et al [ 74 ] ( Figure 2 B).…”

“…An agar well diffusion assay was carried out in order to evaluate the antimicrobial activity of the extracts [ 19 , 20 ]. The pathogenic bacteria were diluted to a concentration of 8 Log CFU/mL and seeded on Tryptone Soya Agar (TSA) (Oxoid) by using sterile swabs.…”

Solid-State Fermentation of Arthrospira platensis to Implement New Food Products: Evaluation of Stabilization Treatments and Bacterial Growth on the Volatile Fraction

“…However, the values remained higher than the inoculation. The L. casei 2240 strain has previously been used to ferment other matrixes, such as Himanthalia elongata , but the growth ability on this brown seaweed was lower than that observed in this study [ 37 ]. The best capacity of this strain to grow on A. platensis can be linked to the high amount of proteins and small peptides [ 2 ].…”

Lactic Acid Fermentation of Arthrospira platensis (Spirulina) in a Vegetal Soybean Drink for Developing New Functional Lactose-Free Beverages

“…Recently, increased demand for fortified food and beverage products with higher nutritional quality from sportsmen, elderly, and children was also observed (Di Cagno et al, 2013;de Marco Castro et al, 2019). Some algae represent a suitable substrate for the production of probiotic lactose-free foods and beverages through lactic acid fermentation due to their high nutritional value and/or valuable components (Gupta et al, 2011;Ścieszka and Klewicka, 2019;Martelli et al, 2020a), e.g., polysaccharides from algae are already recognized and accepted as dietary prebiotics (Jiménez-Escrig et al, 2001;de Jesus Raposo et al, 2016).…”