title: Use of central composite design in food microbiology: a case study on the effects of secondary phenols on lactic acid bacteria from olives.
abstract: This paper focuses on the use of statistical Design of Experiments (DoE) to investigate the effects of two anti-lactic acid bacteria compounds on growth and metabolism of lactobacilli isolated from Italian table olives. p-Coumaric and vanillic acids (0.0-0.4%) were used as phenolic compounds, which were combined with salt (0.0-6.0%) and glucose (0.0-4.0%) through a Central Composite Design. Three strains of Lactobacillus plantarum (5 log cfu/ml) were used as test organisms, samples were stored at 37 °C, and cell counts and pH were evaluated periodically. The growth of lactobacilli was affected in a significant way by salt, p-coumaric and vanillic acids, being the salt the most significant factor after 24 h (short storage time), then replaced by p-coumaric acid. p-Coumaric acid also played a significant role on the acidifying ability, expressed as decrease of pH of the medium: microbial metabolism, in fact, appeared as completely inhibited at 0.2% of p-coumaric acid.
authors.affiliation: Department of the Science of Agriculture, Food and Environment (SAFE), University of Foggia , Foggia , Italy.
authors.forename: Barbara
authors.initials: B
authors.lastname: Speranza
authors.forename: Angela
authors.initials: A
authors.lastname: Racioppo
authors.forename: Milena
authors.initials: M
authors.lastname: Sinigaglia
authors.forename: Maria Rosaria
authors.initials: MR
authors.lastname: Corbo
authors.forename: Antonio
authors.initials: A
authors.lastname: Bevilacqua
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D003373:Coumaric Acids / Q000494:pharmacology*; D005285:Fermentation; D005516:Food Microbiology / Q000706:statistics & numerical data; D005638:Fruit / Q000382:microbiology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D048191:Lactiplantibacillus plantarum / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D031658:Olea / Q000737:chemistry* / Q000382:microbiology; D010636:Phenols / Q000494:pharmacology*; D011422:Propionates; D012965:Sodium Chloride / Q000494:pharmacology; D014641:Vanillic Acid / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D003373:Coumaric Acids; D010636:Phenols; D011422:Propionates; D012965:Sodium Chloride; D014641:Vanillic Acid; C495469:p-coumaric acid
keywords: Central composite design; growth; lactic acid bacteria; pH; phenolic compounds