Vegetable By-Product Lacto-Fermentation as a New Source of Antimicrobial Compounds

Abstract

Background: One of the main objectives of the food industry is the shelf life extension of food products, taking into account the safety requirements and the preference of consumers attracted by a simple and clear label. Following this direction, many researchers look to find out antimicrobials from natural sources. Methods: Tomato, carrot, and melon by-products were used as substrates for lactic acid fermentation using seven strains belonging to the Lactobacillus genus, L. plantarum, L. casei, L. paracasei, and L. rhamnosus. The obtained fermented by-products were then extracted and the antimicrobial activity toward fourteen pathogenic strains of Listeria monocytogenes, Salmonella spp., Escherichia coli, Staphylococcus Aureus, and Bacillus cereus was tested through agar well diffusion assay. Results: All the extracts obtained after fermentation had highlighted antimicrobial activity against each pathogen tested. In particular, a more effective activity was observed against Salmonella spp., L. monocytogenes, S. aureus, and B. cereus, while a lower activity was observed against E. coli. Conclusion: Lactic acid fermentation of vegetable by-products can be a good strategy to obtain antimicrobials useful in food biopreservation.

Effects of different probiotic combinations on the components and bioactivity of Spirulina

“…In terms of antioxidant levels, Choi et al [29] have verified that Spirulina extracts fermented with L. planetarium HY‐08 ameliorated scopolamine‐induced memory impairment in mice. In our study, the mixture of Bacillus strains fermentation showed significant improvement in TFs and TPs contents and the DPPH free‐radical scavenging capacity and total antioxidant capacity, whereas the mixture of lactic acid bacteria fermentation showed stronger inhibitory effects on E. coli , S. typhimurium , and S. aureus , consistent with the previous study on vegetable by‐products fermentation [30]. Moreover, the bioactivity of fermentation products might be due to the use of diversified species such as lactic acid bacteria and Bacillus strains and the metabolites that determined the flavor and function produced by each probiotic or combination of probiotics [31,32].…”

Development of Lactic Acid-Fermented Tomato Products

“…Different authors reported tomato fermentation for different purposes. Some of them apply fermentation as a strategy to recover tomatoes’ by-products for the production of different compounds such as antimicrobials and enzymes using lactic acid bacteria for the fermentation process [ 17 ]. Instead, other authors focused their attention on tomatoes juice lacto fermentation using autochthonous strains or reference strains as starters for fermentation [ 24 , 25 , 26 , 27 , 28 ].…”

“…Before fermentation, strains were revitalized according to Ricci et al [ 17 ]. The starter inoculum was prepared cultivating the strains overnight (15 h), then cells were harvested by centrifugation (10,000 rpm for 10 min at 4 ° C), washed twice with Ringer’s solution (Oxoid, Milan, Italy), and re-suspended in sterile distilled water to reach the final concentration of 9.0 Log CFU/mL.…”

High-Value Compounds in Fruit, Vegetable and Cereal Byproducts: An Overview of Potential Sustainable Reuse and Exploitation

“…The antimicrobial effect might be attributed to the ability of lactic acid bacteria to produce antimicrobial compounds such as organic acids (lactic, acetic and propionic acid), diacetyl, and bacteriocins, as well as their ability to change the metabolic profile of phenols, terpenes, aliphatic alcohols, aldehydes, acids and isoflavonoids, which are useful in food preservation. This promising outcome suggests the possibility of applications of fermented byproduct extracts in food production in order to ensure safety and to extend food shelf life [93]. Lactic acid bacteria and yeast fermentations positively affected the antiradical and antimicrobial activities of discarded leaves of red chicory [94].…”