Unpurified Gelidium-extracted carbohydrate-rich fractions improve probiotic protection during storage

A comprehensive review on the utilization of biopolymer hydrogels to encapsulate and protect probiotics in foods

Probiotics must survive in foods and passage through the human mouth, stomach, and small intestine to reach the colon in a viable state and exhibit their beneficial health effects. Probiotic viability can be improved by encapsulating them inside hydrogel-based delivery systems. These systems typically comprise a 3D network of cross-linked polymers that retain large amounts of water within their pores. This study discussed the stability of probiotics and morphology of hydrogel beads after encapsulation, encapsulation efficiency, utilization of natural polymers, and encapsulation mechanisms. Examples of the application of these hydrogel-based delivery systems are then given. These studies show that encapsulation of probiotics in hydrogels can improve their viability, provide favorable conditions in the food matrix, and control their release for efficient colonization in the large intestine. Finally, we highlight areas where future research is required, such as the large-scale production of encapsulated probiotics and the in vivo testing of their efficacy using animal and human studies.

Yield optimization, physicochemical characterizations, and antioxidant properties of food grade agar from Gracilaria tenuistipitata of Cox's Bazar coast, Bangladesh

The present study was aimed at investigating the optimization of extraction variables for food grade quality agar from Gracilaria tenuistipitata, so far, the first study on Bangladeshi seaweed. Water (native)- and NaOH (alkali)-pretreated agars were comparatively analyzed by several physicochemical parameters. All extraction variables significantly affected the agar yield in both extraction conditions. Alkali-pretreated agar provided a better yield (12-13% w/w) and gel strength (201 g/cm2) in extraction conditions as followed by 2% NaOH pretreatment at 30°C for 3 h, seaweed to water ratio at 1:150, and extraction temperature at 100°C for 2 h. Gelling and melting temperatures, color, and pH values of both agars were found to be comparable with commercial agar. Significantly higher sulfate contents including organic and inorganic and total carotenoids were reported in native (3.14% and 1.29 μg/mL) than that in alkali-pretreated agar (1.27% and 0.62 μg/mL). FTIR spectrum demonstrated the purity of the agar as characterized by the stronger relative intensity with higher degree of conversion of L-galactose 6-sulfate to 3,6-anhydrogalactose in alkali pretreatment group than that of native ones. Moreover, antioxidant activity (% DPPH scavenging) was observed and confirmed by IC50 values of 5.42 and 9.02 mg/mL in water- and alkali-pretreated agars, respectively. The results suggested that agar from G. tenuistipitata with optimized alkali extraction conditions could promote cost-effective yield with improved physicochemical characteristics and biofunctional values upon consumption by the consumers as food materials.

Effect of the molecular structure and mechanical properties of plant-based hydrogels in food systems to deliver probiotics: an updated review

Probiotic products' economic value and market popularity have grown over time as more people discover their health advantages and adopt healthier lifestyles. There is a significant societal and cultural interest in these products known as foods or medicines. Products containing probiotics that claim to provide health advantages must maintain a "minimum therapeutic" level (107-106 CFU/g) of bacteria during their entire shelf lives. Since probiotic bacteria are susceptible to degradation and reduction by physical and chemical conditions (including acidity, natural antimicrobial agents, nutrient contents, redox potential, temperature, water activity, the existence of other bacteria, and sensitivity to metabolites), the most challenging problem for a food manufacturer is ensuring probiotic cells' survival and stability enhancement throughout the manufacturing stage. Currently, the use of plant-based hydrogels for improved and targeted probiotic delivery has gained substantial attention as a potential approach to overcoming the mentioned restrictions. To achieve the best possible results from hydrogels, whether used as a coating for encapsulated probiotics (with the goal of stomach protection) or as carriers for direct encapsulation of live microorganisms should be applied kind of procedures that ensure high bacterial survival during hydrogels application. This paper summarizes polysaccharides, proteins, and lipid-based hydrogels as carriers of encapsulated probiotics in delivery systems, reviews their structures, analyzes their advantages and disadvantages, studies their mechanical characteristics, and draws comparisons between them. The discussion then turns to how the criterion affects encapsulation, applications, and future possibilities.

Characterization and gelling properties of a bioactive extract from Ascophyllum nodosum obtained using a chemical-free approach

The bioactivity and gelling properties of a carbohydrate-rich algal extract obtained from locally harvested Ascophyllum nodosum seaweed using a chemical-free approach were investigated for its potential interest in food applications. Physicochemical characterisation and compositional analysis of the extract, using FTIR, biochemical methods and monosaccharide analysis, confirmed the presence of alginates and fucoidans, although the main polysaccharide present in it was laminarin. Significant amounts of phenolic compounds (~9 ​mg phloroglucinol/100 ​mg sample) were also detected. As a result, the extract exhibited good antioxidant activity. It also showed promising prebiotic potential, promoting the growth of beneficial Lactobacillus sp. and Bifidobacteria sp. when compared with commercial prebiotics, but not that of pathogenic bacteria such as E. coli or P. aeruginosa. The gelling properties of the raw extract were explored to optimize hydrogel bead formation by external gelation in CaCl₂ solutions. This was enhanced at neutral to alkaline pHs and high extract and CaCl₂ concentrations. The mechanical strength, nano- and microstructure of the hydrogel beads prepared under optimised conditions were determined using compression tests, synchrotron small- and wide-angle X-ray scattering (SAXS/WAXS) and scanning electron microscopy (SEM). It was concluded that the raw algal extract at neutral pH had potential for use as a gelling agent, although further enrichment with alginate improved the mechanical properties of the obtained gels. The advantages and disadvantages of applying the non-purified algal extract in comparison with purified carbohydrates are discussed.

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Carbohydrate-rich extract from A. nodosum obtained using a chemical-free process.

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The algal extract exhibited in-vitro antioxidant and prebiotic properties.

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Beads were obtained by external gelation of the extract at neutral to alkaline pH.

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Enrichment with alginate improved the mechanical properties of the gels.

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Components of the extract acted as fillers, reducing structural changes upon drying.

Co-Encapsulated Synbiotics and Immobilized Probiotics in Human Health and Gut Microbiota Modulation

Growing interest in the development of innovative functional products as ideal carriers for synbiotics, e.g., nutrient bars, yogurt, chocolate, juice, ice cream, and cheese, to ensure the daily intake of probiotics and prebiotics, which are needed to maintain a healthy gut microbiota and overall well-being, is undeniable and inevitable. This review focuses on the modern approaches that are currently being developed to modulate the gut microbiota, with an emphasis on the health benefits mediated by co-encapsulated synbiotics and immobilized probiotics. The impact of processing, storage, and simulated gastrointestinal conditions on the viability and bioactivity of probiotics together with prebiotics such as omega-3 polyunsaturated fatty acids, phytochemicals, and dietary fibers using various delivery systems are considered. Despite the proven biological properties of synbiotics, research in this area needs to be focused on the proper selection of probiotic strains, their prebiotic counterparts, and delivery systems to avoid suppression of their synergistic or complementary effect on human health. Future directions should lead to the development of functional food products containing stable synbiotics tailored for different age groups or specifically designed to fulfill the needs of adjuvant therapy.