Abstract

The objective of this study was to develop a dried apple snack enriched with probiotics, evaluate its viability using Refractance Window (RW (TM)) drying, and compare it with conventional hot air drying (CD) and freeze-drying (FD). Apple slices were impregnated with Lacticaseibacillus rhamnosus and dried at 45 degrees C using RW (TM) and CD and FD. Total polyphenol content (TPC), color (triangle E*), texture, and viable cell count were measured, and samples were stored for 28 days at 4 degrees C. Vacuum impregnation allowed for a probiotic inoculation of 8.53 log CFU/gdb. Retention values of 6.30, 6.67, and 7.20 log CFU/gdb were observed for CD, RW (TM), and FD, respectively; the population in CD, RW (TM) remained while FD showed a decrease of one order of magnitude during storage. Comparing RW (TM) with FD, triangle E* was not significantly different (p < 0.05) and RWTM presented lower hardness values and higher crispness than FD, but the RW (TM)-dried apple slices had the highest TPC retention (41.3%). Microstructural analysis showed that RW (TM) produced a smoother surface, facilitating uniform moisture diffusion and lower mass transfer resistance. The effective moisture diffusion coefficient was higher in RW (TM) than in CD, resulting in shorter drying times. As a consequence, RW (TM) produced dried apple snacks enriched with probiotics, with color and TPC retention comparable to FD.