University of Patras; Heriot-Watt University; University of Northumbria; EcoTechSystems srl; University of Northumbria; Democritus University of Thrace; University of Patras; Heriot-Watt University; University of Patras;
Microbial biosurfactants and bioemulsifiers are natural surface active molecules with enormous potential as ingredients in foods and other consumer products. These molecules include low molecular weight surfactants such as the glycolipid rhamnolipids and sophorolipids and polymeric emulsifiers (polysaccharides, proteo-glycans, glyco-proteins or lipoproteins). They are said to be more functional, less toxic, more biodegradable and better for the environment than currently used, often synthetic, counterparts. If these claims are to be verified there is a need to understand better the structure-function relationships in these molecules. Their application in foods has been held back somewhat by a lack of knowledge on their functionality in multicomponent systems, and a dearth of information on their toxic effects both to humans and in the environment. We report results on the structure and properties of rhamnolipid biosurfactant and two novel polymeric bioemulsifiers obtained from marine bacterial strains. Using UHPLC-MS, HPLC-SEC and NMR we can identify the surface active rhamnolipid components and functional groups in the bioemulsifers that suggest the latter are a glycoprotein or proteoglycan and a lipoprotein respectively. This information is linked to functional properties of relevance to foods and how rhamnolipids and microbial polymers interact with food proteins to modify emulsifying, foaming and gelation characteristics. Additionally, we report a full toxicology screen (both on human cell lines and environmental marker organisms) for the molecules. Our results give confidence that biosurfactants and bioemulsifiers are highly functional with low cyto- and environmental toxicity and show great potential as food ingredients.