Gravitational and microwave-assisted multi-stages block freeze concentration process to obtain enriched concentrated beet (Beta vulgaris L.) by-products extract: bioactive compounds and simulated gastrointestinal profile

Polyfunctional sugar-free white chocolate fortified with Lacticaseibacillus rhamnosus GG co-encapsulated with beet residue extract (Beta vulgaris L.)

Chocolate is a worldwide consumed food. This study investigated the fortification of sugar-free white chocolate with Lacticaseibacillus rhamnosus GG microcapsule co-encapsulated with beet residue extract. The chocolates were evaluated for moisture, water activity, texture, color properties, melting, physicochemical, and probiotic stability during storage. Furthermore, the survival of L. rhamnosus GG and the bioaccessibility of phenolic compounds were investigated under in vitro simulated gastrointestinal conditions. Regarding the characterization of probiotic microcapsules, the encapsulation efficiency of L. rhamnosus GG was > 89 % while the encapsulation efficiency of phenolic compounds was > 62 %. Chocolates containing probiotic microcapsules were less hard and resistant to breakage. All chocolates had a similar melting behavior (endothermic peaks between 32.80 and 34.40 °C). After 120 days of storage at 4 °C, probiotic populations > 6.77 log CFU/g were detected in chocolate samples. This result demonstrates the potential of this matrix to carry L. rhamnosus GG cells. Regarding the resistance of probiotic strains during gastric simulation, the co-encapsulation of L. rhamnosus GG with beet extract contributed to high counts during gastrointestinal transit, reaching the colon (48 h) with viable cell counts equal to 11.80 log CFU/g. Finally, one of our main findings was that probiotics used phenolic compounds as a substrate source, which may be an observed prebiotic effect.

Encapsulation of Concentrated Solution Obtained by Block Freeze Concentration in Calcium Alginate and Corn Starch Calcium Alginate Hydrogel Beads

A model (sucrose and gallic acid) solution was concentrated by block freeze concentration (BFC) at three centrifugation cycles, and the solutions were encapsulated in calcium alginate and corn starch calcium alginate hydrogel beads. Static and dynamic tests determined the rheological behavior, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) established thermal and structural properties, and the release kinetics was evaluated under in vitro simulated digestion experiment. The highest efficiency encapsulation value was close to 96%. As the concentrated solution increased in terms of solutes and gallic acid, the solutions were fitted to the Herschel-Bulkley model. Moreover, from the second cycle, the solutions exhibited the highest values of storage modulus (G') and loss modulus (G″), contributing to form a more stable encapsulation. The FTIR and DSC results demonstrated strong interactions between corn starch and alginate, establishing a good compatibility and stability in the bead formation. The kinetic release model under in vitro conditions was fitted to the Korsmeyer-Peppas model, demonstrating the significant stability of the model solutions inside the beads. Therefore, the present study proposes a clear and precise definition for the elaboration of liquid foods obtained by BFC and its incorporation inside an edible material that facilitates the controlled release in specific sites.