Biopreservation of emulsified food and cosmetic products by synergistic action of probiotics and plant extracts: a Franco-Bulgarian perspective

In the context of growing interest for functional foods and cosmetic products, emulsified products such as dressings or lotions have been proposed to deliver probiotics and plant extracts with interesting biological (e. g. anti-inflammatory) properties due to their daily consumption or application on skin, respectively. Besides these positive effects, emulsified products containing water are often prone to microbial growth justifying thus the addition of preservatives such as parabens in their formulation. Safety concerns regarding some synthetic preservatives have stimulated the development of natural antimicrobial ingredients (namely from plant or microbial origin) for the preservation of food or cosmetic products. Besides direct addition of antimicrobial biomolecules, the addition of living bioprotective bacteria such as probiotic lactic acid bacteria (LAB) is a promising approach. Franco-Bulgarian ESCAPE project ambition is to identify synergistic combinations of such probiotic LAB and plant extracts for the preservation of food or cosmetic emulsions. The methodology and the relevant scientific questions (application of hurdle technology principles, selection of plant extracts not affecting LAB growth/viability and antimicrobial activity, distribution of LAB and antimicrobial metabolites in the different phases of emulsions, effect of LAB and plant extracts on emulsions stability…) to tackle this objective are presented and discussed.