Lactobacillus plantarum e Lactobacillus rhamnosus livres e encapsulados incorporados em hambúrguer de carne bovina: um estudo dos impactos e da viabilidade

Abstract

The aim of this work was to evaluate the effect of Lactobacillus plantarum and Lactobacillus rhamnosus addition as free cells and in encapsulated forms, on the physicochemical and microbiological properties of beef burgers during 10 days of refrigerated storage. The capsules were prepared by external ionic gelation, using sodium alginate, powdered milk, green banana flour and xanthan gum as the coating material. Five formulations of beef burgers were prepared: C - without probiotic incorporation; FLP - addition of L. plantarum as free cells; ELP - addition of encapsulated L. plantarum; FLR - addition of L. rhamnosus as free cells; and ELR - addition of encapsulated L. rhamnosus. During the simulated gastrointestinal conditions, the elaborated capsule also provided greater protection for probiotics in all stages of the analysis, with final counts greater than 8 log CFU g-1 . The addition of probiotic strains had a significant effect on the preservation of a* parameter during the storage of beef burgers, especially in ELR treatment. The addition of L. plantarum and L. rhamnosus also affected positively (P < 0,05) the pH, texture and lipid oxidation parameters during the storage. The incorporation of probiotics as free cells or in encapsulated form resulted in higher counts of lactic acid bacteria, L. plantarum and L. rhamnosus in all treatments. However, ELP and ELR maintained higher viability (more than 8 and 11 log CFU g-1 , respectively) over 10 days of refrigerated storage. Furthermore, the incorporation of probiotic strains inhibited (P < 0.05) the proliferation of coliforms during storage. The results showed that both L. plantarum and L. rhamnosus can be used as a biopreservative agent to extend the quality of beef burgers. In addition, the addition of probiotics in encapsulation form showed to be the most effective method to improve the probiotic viability during refrigerated storage and simulated gastrointestinal conditions.