Coating Lacticaseibacillus rhamnosus GG in Alginate Systems: an Emerging Strategy Towards Improved Viability in Orange Juice

Abstract

Fruit juices are successfully proposed as suitable probiotic vehicles, but researchers’ efforts should be developed to avoid effects of bacteria overgrowing on sensory and nutritional cues of final products and to preserve viability of probiotic bacteria during storage. In the present study, encapsulation of Lacticaseibacillus rhamnosus GG strain in alginate systems was performed through ionotropic gelation technology. The alginate systems were optimized by using Box-Behnken Design to investigate the influence of three independent variables at three different levels: particle mean size and polydispersity index. The optimized probiotic-loaded alginate particles were added to orange juice samples. The viability of the probiotic strain, both as free and microencapsulated, was evaluated in orange juice stored at 5°C for 35 days. Morphology and size of probiotic-loaded alginate particles were found suitable for incorporation into juice. TEM analysis revealed that unloaded systems were clustered as nanoparticles (CL_NP), while the loaded sample appeared as a coated system (Coated_LGG). Microbiological evaluation revealed that the encapsulation assured the survival of Coated_LGG, with a reduction of less than 1-unit log in cellular density after 35 days of refrigerated storage in orange juice. Results indicated that the encapsulated bacteria did not affect the macroscopic properties neither the microbiological characteristic of orange juice; thus, it can be proposed as functional food.

Viability of Probiotic Microorganisms and the Effect of Their Addition to Fruit and Vegetable Juices

“…However, divergent results were found in the study by Bonaccorso et al [ 43 ], according to whom pH remained constant for 35-day storage at 5 °C. According to the aforementioned authors, it may have happened due to the reduced metabolism of these bacteria at low temperatures.…”

“…Orange is an important fruit recognized for its sensory and nutritional characteristics and health benefits, as well as being an important source of vitamins, mainly vitamin C, fiber, and minerals. It has high antioxidant capacity due to its high content of bioactive compounds such as ascorbic acid, flavonoids, and carotenoids [ 1 , 22 , 27 , 43 ].…”

“…From another perspective, Olivares et al [ 38 ] and Bonaccorso et al [ 43 ] compared the microbiological features of juices added with free or microencapsulated microorganisms. However, the results in their study were divergent.…”

“…On the other hand, Bonaccorso et al [ 43 ] observed the multiplication of microorganisms such as Leuconostoc spp., mesophiles, psychotrophics, molds and yeasts in orange juice free from prior treatment or the addition of preservatives. Furthermore, the authors observed that the number of microorganisms was higher in samples added with free probiotic bacteria than in those added with microencapsulated microorganisms.…”

Multi-Functional Potential of Lactic Acid Bacteria Strains and Antimicrobial Effects in Minimally Processed Pomegranate (Punica granatum L. cv Jolly Red) Arils

“…Moreover, consumers require healthier food without chemical additives and industries continuously propose novel bio-additive compounds. The exploitation of natural bio-preservatives, or addition of lactic acid bacteria (LAB) and/or their metabolites with antagonistic effects against the deleterious microorganisms are continuously proposed [ 17 , 18 ], and successfully applied for controlling the growth of other microorganisms and/or for enhancing the nutritional values [ 19 ]. In this scenario, the proposal of applying post-biotics has emerged with the advantage of a lower interaction with the food matrix and greater ease of use [ 20 , 21 , 22 ].…”