Avaliação de exopolissacarídeos produzido por bactérias ácido-láticas probióticas, como agente tecnológico em bebida láctea fermentada contendo extrato hidrossolúvel de aveia

Abstract

The present study evaluated the production of exopolysaccharides by Leuconostoc mesenteroides KLM6 and its technological potential in a fermented dairy beverage containing water-soluble oat extract (FDBO). The bacterial strain was selected based on its microbiological safety, including the absence of virulence and resistance genes, as well as its probiotic potential, demonstrated by its ability to auto-aggregate, co-aggregate, adhere to hydrophobic surfaces, and tolerate different concentrations of bile salts. The fermented beverage was formulated with whole milk powder, whey, and water-soluble oat extract, and was tested at different fermentation temperatures and in combinations of L. mesenteroides KLM6 with Streptococcus thermophilus TA40. The study aimed to quantify the production of exopolysaccharides both in vitro and in FDBO, as well as to conduct physicochemical and rheological analyses, assess the viability of the probiotic microorganism, simulate gastrointestinal conditions, and evaluate microbiological and sensory parameters. The fermented dairy beverage with water-soluble oat extract showed the best performance in exopolysaccharide production at 38 °C, reaching a concentration of 175.21 ± 3.44 mg/L in the treatment with combined cultures. During 28 days of refrigerated storage, L. mesenteroides KLM6 maintained good stability, presenting viability of 7.28 ± 0.61 log CFU/mL, which exceeds the minimum required for probiotic effect (> 6 log CFU/mL). FDBO exhibited adequate pH and titratable acidity, low syneresis, good water-holding capacity, and high antioxidant activity. The simulated gastrointestinal tract evaluation demonstrated that L. mesenteroides KLM6 remained viable after exposure to acidic pH, gastric enzymes, bile salts, and pancreatin, reinforcing its survivability under physiological conditions. FDBO received high sensory acceptance for the attributes of color (83%), flavor (87%), aroma (86%), texture (87%), and purchase intent (73%), confirming the product's commercial potential. It was concluded that Leuconostoc mesenteroides KLM6 is a safe, potentially probiotic, and exopolysaccharide-producing strain, capable of improving the technological and functional characteristics of fermented dairy beverages. The oat extract proved to be a promising substrate for application in fermented foods, contributing to the development of innovative products with functional, sensory, and technological appeal.