Viability of probiotic Lactobacillus rhamnosus in structured emulsions containing saturated monoglycerides

Abstract The influence of structured emulsions containing saturated monoglycerides (MG) on the viability of a probiotic Lactobacillus rhamnosus strain during cold storage for up to 56 days was investigated. Six emulsions were prepared, containing sunflower oil or anhydrous milk fat (AMF) as lipid phase, and UHT skim milk or an aqueous solution of potassium bicarbonate or potassium carbonate as water phase, and the probiotic strain. All samples behaved like weak gels, but MG-based emulsion containing AMF show values of storage (G′) and loss (G″) moduli as well as strength significantly higher than those of the samples containing oil. Probiotic strain added as fresh pellet survived the gel preparation procedure regardless the type of MG-based emulsion. During cold storage, bacteria in the MG-based emulsion prepared using skim milk maintained a viability much higher than that of the control and other samples. The proposed approach could offer a way to protect probiotic bacteria and to deliver them into dairy products.