Influence of temperature and solute concentration during osmotic dehydration of apple (Malus domestica) cubes on the stability of probiotics

Currently, there is an upsurge in preference for the consumption of probiotic-rich foods. Besides their nutritive function, these compounds have demonstrated, in some instances, medicinal properties. The purpose of this study was to evaluate how temperature and sucrose concentration influenced the stability of probiotics (specifically Saccharomyces boulardii) during the osmotic dehydration of Granny Smith apple (Malus domestica) cubes. We prepared osmotic solutions with different sucrose concentrations (40, 50, and 60°Brix). We inoculated S. boulardii (250 mg each) into these solutions, followed by immersion of 1 cm-cubed apple cubes. We exposed these cubes to varying temperatures (37°C, 42°C, and 47°C) for a duration of 80 min. Various parameters were calculated, including the percentage of weight loss, percentage of solid gain, number of generations, and the doubling time. Results indicated that the apple cubes with more extreme dehydration were those treated at 50°Brix and 47°C exhibiting a weight loss of 40%. The treatment at 60°Brix and 42°C stood out, showing an increase of 350% of solid gain compared to other groups. Additionally, the highest number of generations of the strain occurred in the group treated at 50°Brix and 37°C, with a value of 9.32 ± 0.11 CFU/g and a doubling time of 7.50 ± 0.09 min. In conclusion, we deduced that under conditions of elevated temperatures and high solute concentrations, the S. boulardii strain might undergo inhibition and fail to develop adequately in the apple cubes subjected to osmotic dehydration.