Preservation of Mimosa tenuiflora Antiaflatoxigenic Activity Using Microencapsulation by Spray-Drying

Mimosa tenuiflora aqueous extract (MAE) is rich in phenolic compounds. Among them, condensed tannins have been demonstrated to exhibit a strong antioxidant and antiaflatoxin B1 activities in Aspergillus flavus. Since antioxidant capacity can change with time due to environmental interactions, this study aimed to evaluate the ability of encapsulation by spray-drying of Mimosa tenuiflora aqueous extract to preserve their biological activities through storage. A dry formulation may also facilitate transportation and uses. For that, three different wall materials were used and compared for their efficiency. Total phenolic content, antioxidant activity, antifungal and antiaflatoxin activities were measured after the production of the microparticles and after one year of storage at room temperature. These results confirmed that encapsulation by spray-drying using polysaccharide wall materials is able to preserve antiaflatoxin activity of Mimosa tenuiflora extract better than freezing.

Exploring in vitro release and digestion of commercial DHA microcapsules from algae oil and tuna oil with whey protein and casein as wall materials

Microencapsulation is a promising technique to improve bioavailability and mask unpleasant smell of DHA oils. Yet, how the encapsulated DHA oils are ‘released’ and ‘digested’ within the gastrointestinal tract (GIT)...

Characterization of Oregano Essential Oil (Origanum vulgare L. subsp. hirtum) Particles Produced by the Novel Nano Spray Drying Technique

Oregano essential oil (OEO), due to its wide variety of biological activities, could be a “green” alternative to chemical preservatives. On the other hand, the difficulties in its use or storage have turned researchers’ interest in encapsulation strategies as a way to face stability and handling issues. Fabrication of OEO-loaded particles, using nano spray drying technique (NSD) and whey protein isolate-maltodextrin mixtures (1:1, 1:3) as wall materials appears to be a novel and promising strategy. The obtained particles were characterized in terms of volatile composition, encapsulation efficiency, and physicochemical, molecular, morphological, and antibacterial properties. The results confirmed that encapsulation of OEO using NSD achieved high levels of powder recovery (>77%) and encapsulation efficiency (>98%) while assisting in the retention of the main bioactive compounds. The partial replacement of WPI by MD significantly affected particles’ physical properties. FTIR analyses revealed the possible structural stabilization of core and wall materials, while SEM verified the very fine size and spherical shape. Finally, antibacterial studies demonstrated their activity against Escherichia coli and Staphylococcus aureus, which is much stronger in comparison with that of pure OEO, proving the positive effect of NSD and particles’ potential in future food applications.

Microencapsulation of Chokeberry Polyphenols and Volatiles: Application of Alginate and Pectin as Wall Materials

Microencapsulation is a rapidly evolving technology that allows preservation of various high-value, but unstable, compounds, such as polyphenols and volatiles. These components of chokeberry juice are reported to have various health-promoting properties. In the present study, hydrogel beads with alginate or alginate and pectin as wall materials and chokeberry juice as active agent were prepared using Encapsulator B-390. The effects of different compositions of wall material as well as the duration of complexation (30 or 90 min) with hardening solution on microencapsulation of chokeberry polyphenols and volatiles were investigated. Spectrophotometric and HPLC analyses showed that beads with pectin addition contained higher concentrations of polyphenols and anthocyanins compared to those prepared with alginate. Antioxidant activities evaluated with FRAP, CUPRAC, DPPH, and ABTS assays followed the same trend. Encapsulation of volatiles which were determined using GC-MS analysis also depended on the composition of hydrogel beads and in some cases on the time of complexation. Results of this study showed that the selection of the wall material is a relevant factor determining the preservation of polyphenols and volatiles. The incorporation of bioactive compounds in hydrogel beads opens up a wide range of possibilities for the development of functional and innovative foods.

Impact of Encapsulation Wall Materials and Drying Method on Physicochemical Properties and Digestibility of Encapsulated Chayote (Sechium edule (Jacq.) Swartz) and Kohlrabi (Brassica oleracea var gongylodes L.) Extracts

Chayote (Sechium edule (Jacq.) Swartz) and kohlrabi (Brassica oleracea var gongylodes L.) are medicinal plants widely distributed in Thailand. Several traditional medicines usually contain these extracts due to their pharmaceutical activities. However, appropriate technologies that are used for protection, stabilization, and slow release of plant extracts are a lot desired in terms of food application. In this study, chayote and kohlrabi extracts were encapsulated by several kinds of wall materials (maltodextrin, and the combination of maltodextrin and gum arabic or alginate) and drying methods (freeze-drying and tray-drying techniques). Thus, the objective of this research was to determine morphological and physicochemical properties, wall materials releasing, and antioxidant activity of encapsulated chayote and kohlrabi extracts powder. The morphology of all encapsulated chayote and kohlrabi extracts powder showed irregular spherical shape, monodispersity, and smooth surface. The encapsulated chayote and kohlrabi extracts powder with tray-drying technique tend to have more darkness and redness in color than the freeze-drying technique. Wall material releasing was expressed in glucose liberation of encapsulated extracts powder after amylolytic enzyme digestion. Encapsulation using maltodextrin as wall material provided higher wall material releasing than the other samples. After digestion analysis, the digested residues were examined for antioxidant activity. The results showed that the combination of maltodextrin and alginate for both freeze-drying and tray-drying techniques provided higher antioxidant activity after 60 and 120 min of digestion. Thus, the combination of maltodextrin and alginate, and drying with the freeze-drying technique was the best treatment in this experiment. This data can lead to a better understanding of wall materials types and releasing characteristics, which are used to control bioactive compounds liberation in the gastrointestinal tract.