Development of alginate-pectin microparticles with dairy whey using vibration technology: Effects of matrix composition on the protection of Lactobacillus spp. from adverse conditions.

In this study, lactic acid bacteria with probiotic potential, including Lactobacillus plantarum ATCC8014, L. paracasei ML33 and L. pentosus ML82, were encapsulated with whey-alginate-pectin (WAP) or whey permeate-alginate-pectin (PAP) by an extrusion process using vibrational technology, with the resulting microparticles assessed for their resistance to adverse conditions. The aim was to assess the effect of the encapsulation wall materials on the viability of microorganisms, the encapsulation, refrigerated storage and simulated gastrointestinal tract conditions, the kinetic parameters of acidification, and the morphology of microparticles. The bacteria encapsulated with the WAP wall material were adequately protected. Furthermore, after three months of storage at 4 °C, the encapsulated bacteria exhibited a cell viability of >6 log CFU mL-1. In addition, the encapsulated L. plantarum ATCC8014 and L. pentosus ML82 isolates exhibited the highest viability at the end of the storage period among the assayed isolates. Encapsulated bacteria showed greater resistance to acidic conditions than unencapsulated bacteria when exposed to simulated gastrointestinal tract conditions. The maximum rate of milk acidification by encapsulated Lactobacillus spp. was approximately three-fold lower than that observed for unencapsulated bacteria. The resulting size of the microparticles generated using both combinations of wall materials used was approximately 150 µm. The cheese whey and whey permeate combined with alginate and pectin to adequately encapsulate and protect Lactobacillus spp. from the adverse conditions of the simulated gastrointestinal tract and from refrigeration storage temperatures. Furthermore, the sizes of the obtained microparticles indicated that the encapsulated materials are suitable for being incorporated into foods without changing their sensory properties.

Characterization of technological and probiotic properties of indigenous Lactobacillus spp. from south Brazil.

In this study, we isolated Lactobacillus spp. from bovine raw milk and artisanal cheese from southern Brazil, and evaluated their technological and probiotic potential to select new isolates for producing healthy fermented dairy foods with differentiated tastes and flavours. We obtained 48 new lactobacilli isolates, which were isolated from raw milk (38) and cheese (10). These bacterial isolates were closely related with ten species: Lactobacillus paracasei (50% of the isolates), L. parabuchneri (15%), L. pentosus (13%), L. zeae (4%), L. plantarum (4%), L. otakiensis (4%), L. casei (4%), L. harbinensis (2%), L. diolivorans (2%), and L. rhamnosus (2%). Isolates CH112 and CH131 showed the greatest acidification potential, reducing the pH of milk to below 5.3 after incubation for 6 h at 32 °C. Considering proteolytic activity and diacetyl production, isolates ML88a, ML04, and ML12 showed the most promising results. Isolate ML12 showed 100% survival rate when inoculated in gastric juice at pH 2.5. The evaluation of antibacterial activity of the lactobacilli showed that the pathogens Listeria monocytogenes, Staphylococcus aureus, Salmonella enteritidis, and Salmonella Typhimurium were strongly inhibited by the pure lactobacilli cultures. Five Lactobacillus isolates (ML01, ML04, ML12, ML88, and CH139) showed both technological and probiotic characteristics. Principal Component Analysis (PCA) was used to investigate correlations among technological and probiotic characteristics, and identified new promising lactobacilli isolates for exploring their characteristics. This study reveals the importance of selecting new microorganisms with potential applicability in the food industry for developing functional foods with differentiated aromas and flavours.

Evaluation of antiradical capacity by H2O2-hemin-induced luminol chemiluminescence.

This paper describes a screening method for antioxidant potential determination based on luminol/hemin/hydrogen peroxide chemiluminescence. The emission depletion, caused by an antiradical compound added during the chemiluminescence decay, is proportional to the number of reactive species trapped. Therefore, the difference between the areas of the emission decay curves, obtained in the absence and in the presence of the potential antioxidant, is a measure for the antiradical capacity of the sample. The technique has been applied to measure the antiradical capacity of pure compounds and complex mixtures from natural origin, providing reliable results that indicate the method's feasibility.