Bifidobacteria as Potential Functional Starter Cultures: A Case Study by MSc Students in Food Science and Technology (University of Foggia, Southern Italy)

Abstract

This research paper was the results of activity of MSc students of Food Science and Technology, attending the class "Biotechnology of Functional Starter". Five strains of bifidobacteria (Bifidobacterium animalis subsp. lactis; B. longum subsp. infantis; B. breve; B. animalis subsp. animalis; B. bifidum) were evaluated in order to assess their suitability as functional starter cultures, by studying the following technological and probiotic traits: growth at different temperatures, NaCl amounts and pH values; acidifying ability; metabolism (arginin deamination, esculin hydrolysis, acetoin production); survival at low pH and in presence of bile salts; hydrophobic properties; antibiotic resistance. After laboratory assays and strain selection through a multivariate analyses, it was highlighted that B. longum subsp. infantis and B. animalis subsp. lactis represent a good compromise as potential functional starter cultures, as B. animalis subp. lactis showed a high growth index at pH 5 and good values at 25 degrees C and 30 degrees C, as well as the minimal viability loss at pH 2.5. B. longum subsp. infantis DSMZ 20088 was the best microorganism for its growth index in presence of 6.5% of salt added and at 25 degrees C and 30 degrees C.