Preservation of viability and anti-Listeria activity of lactic acid bacteria, Lactococcus lactis and Lactobacillus paracasei, entrapped in gelling matrices of alginate or alginate/caseinate

• Published in: Food control Vol. 47; pp. 7 - 19
• Main Authors: Léonard, Lucie, Beji, Olfa, Arnould, Christine, Noirot, Elodie, Bonnotte, Aline, Gharsallaoui, Adem, Degraeve, Pascal, Lherminier, Jeannine, Saurel, Rémi, Oulahal, Nadia
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.01.2015; Elsevier
• Subjects: anti-Listeria spp. activity; Aqueous two-phase system; Biological and medical sciences; Entrapment; Food engineering; Food industries; Fundamental and applied biological sciences. Psychology; General aspects; Hygiene and safety; Lactic acid bacteria; Life Sciences; Sodium alginate; Sodium caseinate; Entrapment; Sodium caseinate; Lactic acid bacteria; anti-Listeria spp. activity; Sodium caseinate (PubChem CID: 5284359); Calcium chloride (PubChem CID: 5284359); Sodium alginate; Sodium alginate (PubChem CID: 6850754); Aqueous two-phase system; Caseinate; Lactococcus lactis; Preservation; Aqueous two-phase system anti-Listeria spp. activity; Food additive; Alginates; Streptococcaceae; Gelling agent; Biphasic system; Listeria; Sodium; Bacteria; Lactobacillaceae; Micrococcales; Lactobacillus delbrueckii subsp. lactis; Viability
• ISSN: 0956-7135; 1873-7129
• DOI: 10.1016/j.foodcont.2014.06.020

In order to control undesirable microorganisms growth in foods, the performance of alginate and alginate–caseinate (an aqueous two-phase system) matrices entrapping lactic acid bacteria (LAB) (Lactobacillus paracasei LAB1 and Lactococcus lactis LAB3) was investigated. Polymeric matrices were initially loaded with LAB cells at ∼108−10 or ∼104−6 CFU mL−1, and were monitored, in liquid and gelled form (beads), for 12 days at 30 °C. In the liquid form, maximum cell density (∼109 CFU mL−1) was reached after 24 h whatever the matrix. Then, the LAB population decreased but remained higher in alginate–caseinate matrices: 107 and 106 CFU mL−1 of LAB3 cells were enumerated after 12 days in alginate–caseinate and in alginate matrices, respectively. Anti-Listeria activity (assayed by agar well diffusion method) did not vary much over 12 days and was also higher for cells entrapped in alginate–caseinate matrices. When matrices were gelled, similar trends were observed: at “Day 12”, LAB3 population was 104−5 and 102−3 CFU/bead, and, LAB1 population was 105−6 and 103−4 CFU/bead, in alginate–caseinate and alginate beads, respectively. Antimicrobial activity of alginate–caseinate beads containing LAB1 cells was quite constant over 12 days. The anti-Listeria activity of LAB cell-free supernatants incorporated in matrices with caseinate was also higher. In fact, the presence of caseinate was shown to promote both the survival of LAB cells and the release of their antimicrobial metabolites. Observation of liquid and gelled matrices by confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) revealed a preferential localization of LAB cells in casein-rich microdomains which could affect favorably the efficiency of bipolymeric matrices. •LAB cells were incorporated in alginate and alginate–caseinate liquid matrices and gels.•Anti-Listeria activity and cells viability were tested for 12 days at 30 °C.•Alginate–caseinate-LAB cells had the highest anti-Listeria activity.•The better release of antimicrobial metabolites could cause this improved activity.•A second factor could be the particular microstructure of aqueous two-phase system.