Encapsulation of Lactobacillus casei in alginate microcapsules: improvement of the bacterial viability under simulated gastrointestinal conditions using flaxseed mucilage

Seed mucilage-based advanced carrier systems for food and nutraceuticals: fabrication, formulation efficiency, recent advancement, challenges, and perspectives

Seed mucilages are potential sources of natural polysaccharides. They are biodegradable, biocompatible, sustainable, renewable, and safe for human consumption. Due to the desirable physicochemical and functional properties (e.g. gelling, thickening, stabilizing, and emulsifying), seed mucilages have attracted extensive attention from researchers for utilization as a promising material for the development of advanced carrier systems. Seed mucilages have been utilized as natural polymers to improve the properties of various carrier systems (e.g. complex coacervates, beads, nanofibers, and gels) and for the delivery of diverse hydrophilic and lipophilic compounds (e.g. vitamins, essential oils, antioxidants, probiotics, and antimicrobial agents) to achieve enhanced stability, bioavailability, bioactivity of the encapsulated molecules, and improved quality attributes of food products. This review highlights the recent progress in seed mucilage-based carrier systems for food and nutraceutical applications. The main contents include (1) sources, extraction methods, and physicochemical and functional characteristics of seed mucilages, (2) application of seed mucilages for the development of advanced carrier systems, (3) major issues associated with carrier fabrication, and (4) mechanisms of carrier development, latest improvements in carrier formulation, carrier efficiency in the delivery of bioactive agents, and application in food and nutraceuticals. Furthermore, major challenges and future perspectives of seed mucilage-based carriers for a commercial application are discussed.

Insights from Syzygium aromaticum Essential Oil: Encapsulation, Characterization, and Antioxidant Activity

Alginate encapsulates loaded with clove essential oil (CEO) were prepared by ionic gelation, with subsequent freeze-drying. The objective of the present work was to develop a product with the ability to protect CEO against its easy volatility and oxidation. The following techniques were used to characterize the formulations: eugenol release, degree of swelling, GC/MS, TGA/DSC, and SEM. The alginate solution (1.0%) containing different concentrations of CEO (LF1: 1.0%; LF2: 0.5%; LF3: 0.1%) was dropped into a 3.0% CaCl2 solution. After lyophilization, the encapsulated samples were wrinkled and rigid, with high encapsulation power (LF3: 76.9% ± 0.5). Three chemical components were identified: eugenol (the major one), caryophyllene, and humulene. The antioxidant power (LF1: DPPH IC50 18.1 µg mL-1) was consistent with the phenol content (LF1: 172.2 mg GAE g-1). The encapsulated ones were thermally stable, as shown by analysis of FTIR peaks, eugenol molecular structure was kept unaltered. The degree of swelling was 19.2% (PBS). The release of eugenol (92.5%) in the PBS solution was faster than in the acidic medium. It was concluded that the low-cost technology used allows the maintenance of the content and characteristics of CEO in the three concentrations tested, offering a basis for further research with essential oil encapsulates.

Enrichment of set yoghurt with flaxseed oil, flaxseed mucilage and free or encapsulated Lacticaseibacillus casei: Effect on probiotic survival and yoghurt quality attributes

This study was intended to develop yoghurt products incorporated with flaxseed mucilage (FM), flaxseed oil (FO) and free or encapsulated Lacticaseibacillus casei probiotics. FM (0.9%) and sodium alginate (2%) were used as wall materials for encapsulating L. casei. Different physicochemical and sensory properties of the yoghurt, as well as the L. casei survival, were determined during 21 days of storage at 4 °C. Based on the results, FM showed a stimulatory effect on the growth of probiotics and thus, significantly decreased the Log reduction of the probiotics during storage (P < 0.05). Moreover, encapsulating probiotics significantly decreased the Log reduction during storage in comparison with the free bacteria (P < 0.05). Incorporating FM and free probiotics significantly increased the acidity and decreased the pH of the samples; while encapsulating L. casei successfully prevented the acidity increment in probiotic fortified yoghurt products (P < 0.05). The addition of FM significantly improved the water holding capacity of the yoghurt (P < 0.05). Incorporating either free L. casei, FO or FM significantly reduced the flavor and overall acceptance scores; while, the addition of L. casei in the encapsulated form did not significantly alter the overall acceptance scores of the yoghurt samples (P < 0.05).

Preparation and Characteristics of Alginate Microparticles for Food, Pharmaceutical and Cosmetic Applications

Alginates are the most widely used natural polymers in the pharmaceutical, food and cosmetic industries. Usually, they are applied as a thickening, gel-forming and stabilizing agent. Moreover, the alginate-based formulations such as matrices, membranes, nanospheres or microcapsules are often used as delivery systems. Alginate microparticles (AMP) are biocompatible, biodegradable and nontoxic carriers, applied to encapsulate hydrophilic active substances, including probiotics. Here, we report the methods most frequently used for AMP production and encapsulation of different actives. The technological parameters important in the process of AMP preparation, such as alginate concentration, the type and concentration of other reagents (cross-linking agents, oils, emulsifiers and pH regulators), agitation speed or cross-linking time, are reviewed. Furthermore, the advantages and disadvantages of alginate microparticles as delivery systems are discussed, and an overview of the active ingredients enclosed in the alginate carriers are presented.

A Review of Extraction Techniques and Food Applications of Flaxseed Mucilage

Flaxseed contains significant concentration of mucilage or gum (a type of hydrocolloid). Flaxseed mucilage (FM) predominantly occurs in the outermost layer of the seed’s hull and is known to possess numerous health benefits such as delayed gastric emptying, reduced serum cholesterol, and improved glycemic control. FM is typically composed of an arabinoxylan (neutral in nature) and a pectic-like material (acidic in nature). Similar to gum arabic, FM exhibits good water-binding capacity and rheological properties (similar functionality); therefore, FM can be used as its replacement in foods. In this review, an overview of methods used for FM extraction and factors influencing the extraction yield were discussed initially. Thereafter, food applications of FM as gelling agent/gel-strengthening agent, structure-forming agent, stabilizing agent, fat replacer, anti-retrogradation agent, prebiotic, encapsulating agent, edible coatings and films/food packaging material, and emulsifier/emulsion stabilizer were included. At the end, some limitations to its wide application and potential solutions were added.

Effective encapsulation of reuterin-producing Limosilactobacillus reuteri in alginate beads prepared with different mucilages/gums

The mainly aim of this study was to use mucilaginous solutions obtained from tamarind, mutamba, cassia tora, psyllium and konjac powdered to encapsulate reuterin-producing Limosilactobacillus reuteri in alginate beads by extrusion technique. In the particles were determined the bacterial encapsulation efficiency, cell viability during storage and survival under simulated gastric and intestinal conditions. Moreover, the reuterin production, its entrapment into the beads and the influence on viability of encapsulated microorganism were evaluated. Scanning electron microscopy and Fourier Transform Infrared spectroscopy were employed to characterize the produced particles. The beads showed a relatively spherical shape with homogenous distribution of L. reuteri. The use of gums and mucilages combined with alginate improved the encapsulation efficiency (from 93.2 to 97.4%), the viability of encapsulated bacteria during refrigerated storage (especially in prolonged storage of 20, 30 and 60 days) and the survival after exposure to gastric and enteric environments (from 67.7 to 76.6%). The L. reuteri was able to produce reuterin via bioconversion of glycerol in the film-forming solutions, and the entrapment of the metabolite was improved using konjac, mutamba and tamarind mucilaginous solutions in the encapsulation process (45, 44.57 and 41.25%, respectively). Thus, our findings confirm the great potential of these hydrocolloids to different further purposes, enabling its application as support material for delivery of chemical or biological compounds.

Microencapsulation of Lactobacillus rhamnosus GG with flaxseed mucilage using co-extrusion technique

AIM

This study aimed to evaluate the protective effect of flaxseed mucilage on the co-extrusion microencapsulation of Lactobacillus rhamnosus GG.

METHODS

Core flow rate, chitosan coating, and flaxseed mucilage concentration were optimised for the microencapsulation of L. rhamnosus. The microbeads were characterised and evaluated on microencapsulation efficiency and cell released after 6 h of sequential digestion.

RESULTS

The optimised parameters for the L. rhamnosus microencapsulation were 1.0 mL/min core flow rate, 0.4% (w/v) chitosan coating, and 0.4% (w/v) flaxseed mucilage. The L. rhamnosus microbeads with flaxseed mucilage in core and wall materials had a smooth surface with 781.3 µm diameter, the highest microencapsulation efficiency (98.8% w/w), lowest swelling (5196.7% w/w) and erosion ratio (515.5% w/w), and least cell release (<40% w/w) with 9.31 log₁₀ CFU mL^-1 after sequential digestion.

CONCLUSIONS

This study showed the protective capacity of flaxseed mucilage towards the L. rhamnosus GG during microencapsulation and gastrointestinal environment.