Microencapsulation of Lacticaseibacillus rhamnosus GG and L. plantarum 299 V by reverse spherification: a promising method to improve the survival of probiotics.

This research reports the first application of the reverse spherification (RVS) method for encapsulation of two probiotics (Lacticaseibacillus rhamnosus GG and L. plantarum 299 V) compared to the basic spherification (BS). These probiotics were encapsulated in different solutions encompassing various contents of alginate, gelatin, and gellan gum. The RVS bead diameters was about 1.5 times bigger and hardness was 70%-80% lower than BS samples. As determined by Raman spectral mapping, the RVS beads had two calcium alginate walls but the BS beads had only one. The inner wall of the RVS beads was more than three times thicker than outer wall. The encapsulation yields of gelatin/gellan gum and gelatin beads prepared by both methods were >1.5% alginate beads. All the RVS-prepared beads were resistant to stomach acid and showed no significant reduction in the intestine. Furthermore, the incorporation of gelatin and gellan gum into alginate led to higher cell protection. For 1.5% alginate beads, <67% survival was achieved after acid exposure but in others, >77% survival was observed; RVS beads were about 1 log above than BS ones. The proposed novel microencapsulation method efficiently increased the viability of probiotic bacteria compared to the conventional approaches.

Evaluating the Effects of Microwave-Assisted Hydrodistillation on Antifungal and Radical Scavenging Activities of Oliveria decumbens and Chaerophyllum macropodum Essential Oils.

In this study, radical scavenging and antifungal activities of Chaerophyllum macropodum and Oliveria decumbens essential oils (EOs) extracted with microwave-assisted hydrodistillation (MAHD) were evaluated in comparison with the same EOs extracted by conventional hydrodistillation (HD). The final EO yields that were obtained using HD (after 150 min) and MAHD (after 45 min) were 1.72 and 1.67% for C. macropodum and 8.10 and 7.91% for O. decumbens, respectively. There were no significant differences between the final EO yields extracted with HD and MAHD, but MAHD could significantly reduce the duration of the extraction operation. Average rates of EO accumulation (grams per minute) with MAHD were at least three times higher than with HD. Gas chromatography-mass spectrometry analysis of EOs indicated that there were no significant differences between the composition of EOs extracted by HD and MAHD. Both plants showed high radical scavenging activity, with 50% inhibitory concentration values of 0.430 to 0.431 mg/mL for C. macropodum and 0.142 to 0.146 mg/mL for O. decumbens. Antifungal activity was performed against six fungal species, including Aspergillus niger, Aspergillus oryzae, Penicillium chrysogenum, Trichoderma harzianum, Byssochlamys spectabilis, and Paecilomyces variotii. A. niger and A. oryzae were the most resistant fungi, and T. harzianum was the most susceptible. Evaluation of MIC and minimum fungicidal concentration values showed that the O. decumbens EOs were very active against all the tested fungi, which can be attributed to the high amounts of oxygenated terpenes in the EO content. Therefore, MAHD as a fast extraction technique did not have any adverse effects on chemical composition, radical scavenging activity, and antifungal activity of C. macropodum and O. decumbens EOs.