Desenvolvimento e caracterização de cápsulas probióticas contendo Lactobacillus Rhamnosus

Abstract

Encapsulation is a technique that can be used for the protection of probiotics, conferring resistance to the acidic environment of the gastrointestinal tract allowing its use in fermented milk products. The present study had as objective evaluates the best encapsulation concentrations of L. rhamnosus using alginate of sodium, pectin and gelatin. Two experimental designs were conducted to capsules containing alginate and gelatin and pectin and gelatin. The variables investigated were concentrations of polymer and the dependent variable was the concentration of viable cells in the capsules. The highest concentration of viable cells (4.2 x 109 CFU/g) was achieved for concentrations of 1 % alginate and 0.1 % gelatin, whereas the concentration of alginate was variable that affected the response variable most significantly, reaching a negative estimated effect of -4.59. Statistical evaluation of the results obtained with microcapsules of pectin was not satisfactory. Results of IR spectra show that the three samples that were analyzed contain the alginate. The spectra shows peaks due to O−H group in the region of 3400−3454 cm−1. The spectra of Microcapsules shows a peak between 1637 cm−1 and 1639 cm−1 confirming the presence of the functional group –CONH2 that is present in the gelatin, whereas pure alginate does not show this peak. Thermal analysis of the material indicates a glass transition temperature (Tg) above the storage temperature of the microcapsules, which ensures the crystallization of the microcapsules. After 120 days of storage under refrigeration capsules have reached the concentration of 105UFC/mL, still being suitable for incorporation in food. Regarding the incorporation of the microcapsules and the free cells in the fermented milk, the free cells obtained by addition of L. rhamnosus ATCC 7469, presented the minimum score needed for a product to be considered probiotic. The microcapsules produced by the extrusion technique with alginate as encapsulating agents were suitable for microencapsulation of these probiotics, while microcapsules obtained were not satisfactory with pectin.