PROBIOTICS AND TEXTURE PROFILE: LACTICASEIBACILLUS RHAMNOSUS IN FERMENTED MILK DIRECTED TO SENIOR CONSUMERS WITH DYSPHAGIA

The increase in life expectancy has led to a significant expansion in the population of individuals over 60 years old, a group that is expected to reach 22% of the global population by 2050. With advancing age, psychomotor and physiological mechanisms become impaired, alongside an increase in chronic diseases, cognitive decline, and deficiencies in food intake due to syndromes such as dysphagia, as well as impaired nutrient absorption caused by gut microbiota dysbiosis. Therefore, strategies such as food supplementation with probiotic strains are recommended for individuals requiring higher nutritional support. Dairy products are source of essential macronutrients and excellent vehicles for promoting the consumption of probiotics due to culture adaptability, product versatility, and sensory acceptance. Lacticaseibacillus rhamnosus, in addition to its proven probiotic effect, is a filamentous culture capable of altering product viscosity through the production of exopolysaccharides. These biopolymers have been applied as an alternative to commercial thickeners, enabling in situ production of products adequate for the dysphagic population. Thus, this study aimed to evaluate the use of Lacticaseibacillus rhamnosus LRB, combined with a starter culture, as a strategy to modify texture properties of fermented milk, focusing on the development of a product tailored to dysphagic individuals. The fermented milks were produced by reconstituting skimmed milk powder at 13% total solids, heat-treated (85 °C/30 min), and immediately cooled in an ice bath. The samples were coded as ST (control), inoculated solely with the Streptococcus thermophilus starter culture (3%); SL1 (starter culture 3% and probiotic 1%); and SL2 (starter culture 3% and probiotic 2%). Process monitoring was performed through a fermentation curve up to pH 4.5, microorganism viability was evaluated by standard plate count, and technological characteristics were determined by water-holding capacity via centrifugation and supernatant weighing, viscosity profile, and flow test as described in the International Dysphagia Diet Standardization Initiative (IDDSI), assessing time-dependent dripping in a 10 mL slip-tip syringe. The L. rhamnosus count was 3.4x107 and 8.0x107 CFU/mL of product for SL1 and SL2, respectively. The addition of the probiotic did not affect the water-holding capacity of the fermented milks. However, the addition of 2% of the microorganism resulted in higher viscosity for SL2 (2,866.66 ± 295.14 cP; p < 0.05) compared to ST (2,326.67 ± 163.3 cP) and SL1 (2,668.333 ± 330.62 cP). According to the IDDSI classification, SL2 differed from the other samples, being classified as a moderately thick liquid, whereas ST and SL1 are considered mildly thick liquids. Thus, the use of L. rhamnosus LRB as an adjunct culture in fermented milks offers an alternative that combines bioactivity and technofunctionality with texture enhancement of fermented milk for consumers with dysphagia limitations.