Caracterização de exopolissacarídeo obtido de soro de leite fermentado por Lactiplantibacillus plantarum e sua utilização como agente encapsulante de bactéria probiótica

Abstract

Lactic acid bacteria are used due to their probiotic potential, in addition to being able to produce bioactive substances. Therefore, it is known that the product generated by them depends on the substrate used. Whey is a by-product that can be a low-cost alternative for the production of these substances through fermentation by the action of lactic acid bacteria. The integration of the compound obtained with an emerging technology, such as encapsulation, may be able to ensure bioactivity. The present work aimed to characterize the exopolysaccharide obtained from fermented whey (EPS-LN60) by Lactiplantibacillus plantarum DF60Mi and use it as an encapsulating agent for probiotic bacteria. The prebiotic score, antioxidant activity and cytotoxicity of EPS-LN60 were determined. Solutions of 0% (F0), 0.5% (F1) and 1.0% (F2) of EPS-LN60 were produced and used as a cover for alginate capsules containing L. acidophilus LA-3 and evaluated for morphology, survival of LA-3 during storage and after exposure to simulated gastrointestinal conditions. The EPS yield obtained was 777 mg/L, with 43.78% of total sugars and 1.82% of proteins. The EPS spectrogram showed bonds and functional groups compatible with carbohydrate polymers, as well as high thermal stability (310 °C), providing potential industrial application. The monosaccharide composition showed the presence of galactose (51.1%), mannose (22.9%), glucose (20.8%) and rhamnose (5.2%), resulting in a heteropolysaccharide. The EPS prebiotic score (1.45 ± 0.17) was higher than that of the fructooligosaccharide (0.24 ± 0.05), the antioxidant activity was relevant at 1862 ± 23.08 µM FeSO4/g and there was an inhibition of 36 ± 2.78% of tumor cell growth (HCT-116) in vitro. The F1 and F2 capsules with EPS-LN60 were spherical and uniform, and the coating allowed approximately 85% survival of the LA-3 strain after 20 days. F0 did not have viable cells after 10 days. During the gastrointestinal simulation conditions, EPS was responsible for keeping the survival of the LA-3 strain above 86%. Therefore, the potential of EPS-LN60 was demonstrated in terms of its bioactivity and use as an encapsulating agent for the LA-3 strain, envisioning its exploitation as a functional ingredient by the food and pharmaceutical industries.