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. As phenolic compounds were used p-coumaric and vanillic acids (0.0-0.4%) that were combined with salt (0.0-6.0%) and glucose (0.0-4.0%) through a Central Composite Design. As test organisms were used three strains of Lactobacillus plantarum (5 log cfu/ml); 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 played also 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.
Use of Central Composite Design in food microbiology: a case study on the effects of secondary phenolis on lactic acid bacteria from olives
SPERANZA, BARBARA;RACIOPPO, ANGELA;SINIGAGLIA, MILENA GRAZIA RITA;CORBO, MARIA ROSARIA;BEVILACQUA, ANTONIO
2015-01-01
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. As phenolic compounds were used p-coumaric and vanillic acids (0.0-0.4%) that were combined with salt (0.0-6.0%) and glucose (0.0-4.0%) through a Central Composite Design. As test organisms were used three strains of Lactobacillus plantarum (5 log cfu/ml); 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 played also 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.