Antimicrobial potential of LEGUMES extracts against foodborne pathogens: A review

[EN] Background: Alternative protein sources are being investigated in response to increasing consumer demand for innovative and healthy food products of vegetable origin to replace non-sustainable animal exploitation. The Leguminosae family includes a wide variety of plants and nutritious seeds, very rich in protein with a high biological value, carbohydrates, vitamins and minerals. Not only the seeds but also the aerial parts, pods, hulls and roots have proved to be natural sources of antioxidants, and anti-inflammatory and antimicrobial compounds. Scope and approach: The present article overviews the antimicrobial potential of the most popular legumes worldwide against foodborne pathogens. Key findings and conclusions: According to the literature reviewed, soybean and chickpea are the two consumed legumes with the highest antimicrobial activity. Long-chain soy peptides (IKAFKEATKVDKVVVLWTA) have a high antimicrobial potential against both Gram-positive and Gram-negative bacteria at a concentration level of 37.2 ¿M. Also, a wide spectrum of proteins and peptides in raw chickpeas and processed extracts have exerted antimicrobial activity against foodborne pathogens when applied in the range 8¿64 ¿g/ml. These results open a new research line with good prospects regarding the development of a new generation of natural preservative ingredients and extracts to be included in novel formulated products. However, critical aspects, such as (i) the stability of antimicrobial activity during the shelf-life of newly formulated food products, and (ii) the microbial inactivation kinetics generated in novel matrices, should be covered prior to exploitation of legumes as sources of novel technological ingredients with antimicrobial potential.The present research work has been supported by funds provided by the Spanish Ministry of Economy and Competitiveness (MINECO) as the HELICOFOOD project, with reference AGL2014-53875-R. The post-doctoral contract of M.C. Pina-Pérez as Juan de la Cierva-Incorporación granted by the MINECO is also acknowledged.Pina Pérez, MC.; Ferrús Pérez, MA. (2018). Antimicrobial potential of LEGUMES extracts against foodborne pathogens: A review. Trends in Food Science & Technology. 72:114-124. doi:10.1016/j.tifs.2017.12.007S1141247

Investigation of the antimicrobial activity of soy peptides by developing a high throughput drug screening assay

Background: Antimicrobial resistance is a great concern in the medical community, as well as food industry. Soy peptides were tested against bacterial biofilms for their antimicrobial activity. A high throughput drug screening assay was developed using microfluidic technology, RAMAN spectroscopy, and optical microscopy for rapid screening of antimicrobials and rapid identification of pathogens. Methods: Synthesized PGTAVFK and IKAFKEATKVDKVVVLWTA soy peptides were tested against Pseudomonas aeruginosa and Listeria monocytogenes using a microdilution assay. Microfluidic technology in combination with Surface Enhanced RAMAN Spectroscopy (SERS) and optical microscopy was used for rapid screening of soy peptides, pathogen identification, and to visualize the impact of selected peptides. Results: The PGTAVFK peptide did not significantly affect P. aeruginosa, although it had an inhibitory effect on L. monocytogenes above a concentration of 625 μM. IKAFKEATKVDKVVVLWTA was effective against both P. aeruginosa and L. monocytogenes above a concentration of 37.2 μM. High throughput drug screening assays were able to reduce the screening and bacterial detection time to 4 h. SERS spectra was used to distinguish the two bacterial species. Conclusions: PGTAVFK and IKAFKEATKVDKVVVLWTA soy peptides showed antimicrobial activity against P. aeruginosa and L. monocytogenes. Development of high throughput assays could streamline the drug screening and bacterial detection process. General significance: The results of this study show that the antimicrobial properties, biocompatibility, and biodegradability of soy peptides could possibly make them an alternative to the ineffective antimicrobials and antibiotics currently used in the food and medical fields. High throughput drug screening assays could help hasten pre-clinical trials in the medical field

Characterization of antimicrobial efficacy of soy isoflavones against pathogenic biofilms

Pathogenic biofilms that form on food processing equipment/surfaces are of great concern, because these can readily lead to food spoilage, bio-fouling, food-borne illness, and their recalcitrance can result in the acquisition of multi-drug resistance. Currently available coatings do not completely inhibit microbial growth and an increased demand for such coatings means that new products will need to be developed. The unique properties of antimicrobial soy isoflavones, including their biodegradability, biocompatibility, and lack of toxicity as edible products, make their application more appealing than artificial polymer or chemical-based coatings. In this study, we evaluated the antimicrobial efficacy of soy isoflavones against pathogenic biofilms of Listeria monocytogenes, Escherichia coli, Pseudomonas aeruginosa, and Methicillin-Resistant Staphylococcus aureus (MRSA) using microtiter plate assays (MPAs), scanning electron microscopy (SEM), and atomic force microscopy (AFM). Ultrasonication technique yielded 491μg of isoflavones per gram of soy flour sample. MPA assays and the imaging experiments revealed that the establishment of L.monocytogenes and E.coli biofilms was inhibited by 10μg/mL and 100μg/mL soy isoflavones, while MRSA and P.aeruginosa were largely unaffected