Lactulose in combination with soybean lecithin has a cryoprotective effect on probiotic taxa of bifidobacteria and Lactobacillaceae.

This article focuses on evaluating the cryoprotective effect of a combination of lactulose, a prebiotic disaccharide, and lecithin, an essential nutrient component, on probiotic bacteria from the bifidobacteria and Lactobacillaceae families during long-term storage at mild freezing temperature (−20°C). Using 12 probiotic strains, the study found that the lactulose plus lecithin (LL) solution provided a cryoprotective effect comparable to 25% glycerol, a standard cryoprotectant, maintaining viable cell counts above the therapeutic minimum (>10^7 CFU/mL) in most strains after 210 days. Results indicated better survival rates in bifidobacteria than Lactobacillaceae and revealed strain-dependent responses to the cryoprotective agents. The findings suggest that lactulose combined with lecithin could support the development of new frozen or freeze-dried probiotic and synbiotic formulations, termed nutriprobiotics and nutrisynbiotics, enhancing long-term preservation and potential health benefits.