Ultrasound attenuation of lactobacilli and bifidobacteria: Effect on some technological and probiotic properties

• Published in: International journal of food microbiology 2017-02, Vol.243, p.78-83
• Main Authors: Racioppo, Angela, Corbo, Maria Rosaria, Piccoli, Claudia, Sinigaglia, Milena, Speranza, Barbara, Bevilacqua, Antonio
• Format: Article
• Language: English
• Subjects: Acid resistance; Acidification; Attenuation; Bacteria; Bacterial Adhesion; Beverages; Bifidobacterium - growth & development; Bifidobacterium - metabolism; Bile; Bile Acids and Salts - pharmacology; Caco-2 Cells; Cell Line, Tumor; Cells; Growth; Humans; Hydrogen-Ion Concentration; Hydrophobic and Hydrophilic Interactions; Hydrophobicity; Lactic acid; Lactic acid bacteria; Lactobacilli; Lactobacillus plantarum; Lactobacillus plantarum - growth & development; Lactobacillus plantarum - isolation & purification; Lactobacillus plantarum - metabolism; Lactobacillus reuteri - growth & development; Lactobacillus reuteri - metabolism; Metabolism; Microbial Viability; Microbiology; pH effects; Probiotics; Properties (attributes); Sodium chloride; Sonication; Strains (organisms); Ultrasonic Waves; Ultrasound
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2016.12.011

Attenuation can be regarded as a tool to modulate the metabolism of probiotic bacteria and, consequently, a strategy to reduce the acidification of the active drinks. Attenuation can be done through chemical and physical approaches and ultrasound (US) is a possibility, previously tested to modulate the metabolism of lactic acid bacteria inoculated in a rice drink, but no data are available on the effect of this treatment of the overall profile of probiotic bacteria. Therefore, the main topic of this paper was to study the effect of US-attenuation on some properties of Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, and Bifidobacterium infantis (survival at pH2, and 2.5, and with 0.3% of bile salt added, hydrophobicity, acidification, and growth at different temperatures, pH or in presence of 7% NaCl). A preliminary screening was done by using 3 power levels (40, 60, and 80%) and 3 different treatment times (2, 4, and 6min); immediately after sonication, acidification and viable count were tested. The best combination to avoid post-acidification was the following one: power, 60%; time, 6min; pulse, 2s. The effect of this combination on the overall profile of the test strains (functional and technological properties) was studied. This combination exerted a positive effect on the hydrophobicity and adhesion to Caco-2 cells of L. reuteri, although the growth at pH4 was negatively affected. In the other strains, there a was negative effect on acid and bile resistance. •US can be used to perform attenuation on lactobacilli and bifidobacteria.•The effect of attenuation can be enhanced by refrigeration.•US-attenuation increases the adhesion of Lactobacillus reuteri to Caco cells.•Acid and bile sensitivity of treated bacteria should be improved.