Microencapsulação de culturas probióticas por spray drying utilizando diferentes agentes encapsulantes

Abstract

Functional products have played an important role in the food industry because they have beneficial health properties for consumers. In this context, there are probiotic bacteria, which, due to their innumerable benefits, have been highlighted and today comprise approximately 65% of the world market for functional foods. However, despite the application of these microorganisms in the food industry, the maintenance of their viability is well discussed and studied, since probiotics are highly sensitive to environmental factors and also to the passage through the gastrointestinal tract. Thus, microencapsulation presents itself as a promising method to provide a suitable coating for such microorganisms, so that they can remain viable and reach their site of action in suitable amounts. In this work, different encapsulation matrices for the spray-drying microencapsulation process were studied in order to provide greater protection for Lactobacillus acidophilus La-5 and Bifidobacterium Bb-12, aiming at high survival rates and higher encapsulation efficiency (EE %). First, formulations composed of maltodextrin and gum arabic with Lactobacillus acidophilus La-5 (ML) and Bifidobacterium BB-12 (MB) were dried under different inlet air temperature conditions in the spray drier. The inlet temperature of 130 °C was chosen to provide microparticles with higher viability, lower water activity and humidity for both microencapsulated microorganisms. The microparticles of Lactobacillus acidophilus La-5 and Bifidobacterium Bb-12 with the different encapsulating matrices were produced, being: inulin (MS2), hi-maize (MS3) and trehalose (MS4) and the control sample (MS1). The different microparticles (MS1, MS2, MS3 and MS4) were evaluated for their resistance to heat treatments, simulated gastrointestinal conditions and different storage conditions. The morphology and average size of the different particles were also determined. For Lactobacillus acidophilus La-5 hi-maize (94.26%) and inulin (93.12%) were the encapsulating matrices that presented the highest encapsulation efficiency. Therefore, for Bifidobacterium Bb-12 hi-maize (95.24%) and trehalose (90.10%) confer greater encapsulation efficiency. The average size of the microparticles ranged from 6.68 to 20.9 μm and morphology showed that they were in spherical shape and with concavities. In the evaluation of resistance to heat treatments, gastrointestinal simulation and in the storage conditions, the matrices encapsulantes hi-maize and trehalose were the ones that demonstrate greater potential of protection for both microorganisms studied. Finally, the results of this study showed that the use of hi-maize and trehalose improved the viability and consequently the survival of Lactobacillus acidophilus La-5 and Bifidobacterium Bb-12 showing that these encapsulating matrices had high thermoprotective potential for microencapsulated probiotic cultures in spray dryer.