Food additive carrageenan: Part II: A critical review of carrageenan in vivo safety studies

Dietary Carrageenan Amplifies the Inflammatory Profile, but not Permeability, of Intestinal Epithelial Cells from Patients With Crohn's Disease

BACKGROUND

The consumption of ultra-processed foods has increased significantly worldwide and is associated with the rise in inflammatory bowel diseases. However, any causative factors and their underlying mechanisms are yet to be identified. This study aimed to further elucidate whether different types of the dietary emulsifier carrageenan (CGN) can alter the permeability and inflammatory state of the intestinal epithelium.

METHODS

Caco-2/HT29-MTX cocultures (n = 4) were exposed to either κ-, ι-, or λ-CGN (100 µg mL-1) for 24 hours. Organoid-derived monolayers from patients with Crohn's Disease (CD) were exposed to κ-CGN (100 µg mL-1) for 48 hours (n = 10). In both models, an inflamed condition was established by adding a mix of inflammatory stimuli. Changes in permeability were measured by transepithelial electrical resistance (TEER). In the organoid-derived monolayers, cytokines were quantified in the apical and basolateral supernatant and gene expression was analyzed with RT-qPCR.

RESULTS

None of the CGN subtypes altered permeability of non-inflamed or inflamed Caco-2/HT29-MTX cocultures. In organoid-derived monolayers, κ-CGN did not affect TEER, but induced alterations in the gene expression of tight junctions and mucus proteins. Expression of TNF, IL8, and IL1B increased upon κ-CGN stimulation, both in inflamed and non-inflamed monolayers. Cytokine release in the supernatant was increased by κ-CGN for IL-6, IL-13, IL-4, IL-2, and IL-10.

CONCLUSIONS

Dietary CGN caused upregulation of inflammatory markers and affected cytokine release of intestinal epithelial cells from CD patients, while permeability remained unaltered. When inflammation was already present, this pro-inflammatory effect was more pronounced, suggesting a role for dietary CGN during active CD.

Evaluation of In Vitro Toxicity of OrPhyllo™, a New Vehicle to Produce Orodispersible Films

Orodispersible films (ODFs) are advanced drug delivery systems that consist of thin, mechanically robust polymeric films designed to dissolve or disintegrate quickly in the oral cavity, facilitating local and systemic drug administration. Orphyllo™ is a novel ODF vehicle developed to enhance the stability and delivery efficiency of active pharmaceutical ingredients. This study aimed to assess the safety profile of Orphyllo™ through a comprehensive evaluation of its cytotoxicity and genotoxicity on human oral mucosa cell lines. The cytotoxicity was evaluated using (3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide) MTT, Neutral Red Uptake (NR), and Lactate Dehydrogenase (LDH) assays, which tested the impact of Orphyllo™ at concentrations of 5.0% and 10.0% over 24, 48, and 72 hours. Results indicated no significant reduction in cell viability (P > 0.05), demonstrating the formulation's biocompatibility. To evaluate genotoxicity, the micronucleus test was performed, showing no significant increase in the frequency of micronuclei compared to the control group, thus indicating no DNA damage. Additionally, the Annexin/7-AAD assay was employed to assess apoptosis and necrosis, revealing no significant induction of cell death at the tested concentrations (P > 0.05). These findings highlight that Orphyllo™ presents, even at an early stage, the potential to become a promising vehicle for oral drug administration applications, with potential benefits in several therapeutic areas, especially for populations that require ease of administration.

κ-Carrageenan from Grateloupia filicina protects against PM2.5-induced intraocular pressure elevation

This study investigates the efficacy of GFP01, an almost pure κ-carrageenan derived from Grateloupia filicina, in counteracting intraocular pressure (IOP) elevation induced by PM2.5 exposure. GFP01, characterized by a molecular weight of 97.8 kDa, exhibits a linear backbone composed of 4-O-sulfated-β-D-galactose and 3,6-anhydro-α-D-galactose. In a murine model subjected to PM2.5-induced high IOP, GFP01 treatment significantly mitigated IOP compared to the PM2.5 group (n = 12, p < 0.01). In vitro assays revealed a 27.7 % increase in cell viability in human trabecular meshwork cells (HTMCs) treated with GFP01 compared to controls exposed to PM2.5 (p < 0.001, n = 5 cell lines). Additionally, GFP01 decreased PM2.5-induced transendothelial electrical resistance (TEER) of angular aqueous plexus (AAP) cells by 35.8 % at 48 h post-treatment (p < 0.05, n = 3 cell lines). Western blot analysis further demonstrated GFP01's role in inhibiting NLRP3/caspase-1/GSDMD/IL-1β axis in ocular tissues and HTMCs. Cytotoxicity assessment and slit-lamp imaging confirmed the safety of GFP01. In conclusion, GFP01 demonstrates a significant protective effect against PM2.5-induced IOP elevation, making it a promising therapeutic candidate for clinical applications.

Effect of Food Matrix on Regulation of Intestinal Barrier and Microbiota Homeostasis by Polysaccharides Sulfated Carrageenan

Carrageenan (CGN) has side effects on the intestinal barrier. Damage to the intestinal barrier is associated with exposure to sulfate groups. Food matrix has significant influence on the exposure quantity of sulfate groups and conformation in κ-CGN, but the corresponding side effects are not reported specifically. This study aimed to explore the regulatory effect of κ-CGN dissolved in aqueous (κ-CGN) and in 3% casein (κ-carrageenan-casein, κ-CC) on the intestinal barrier and microbiota homeostasis. Research has shown that both κ-CGN and κ-CC can induce different extents of intestinal barrier damage through disrupting microbiota homeostasis. Importantly, κ-CGN in casein with lower sulfate groups content was found to repair the intestinal barrier injury induced by an equivalent dose of κ-CGN aqueous through increasing the abundance of Oscillibacter and decreasing Weissella. These alleviating effects were reflected in lower levels of tumor necrosis factor (TNF)-α and C-reaction protein (CRP), higher levels of interleukin (IL)-10, raised secretion of mucus and goblet cells, and improved expression of epithelial cell compact proteins zonula occluden (ZO)-1 and mucin protein 2 (MUC2). This study states that κ-CGN in casein has a positive regulatory effect on the intestinal barrier damage compared to in aqueous solution, which can provide guidance for processing and utilization of CGN.

Food additives and their implication in inflammatory bowel disease and metabolic syndrome

Over the past half a century the Western diet (WD) has become saturated with food additives. During the same time, there has been an increase in Western diseases, such as inflammatory bowel disease (IBD) and metabolic syndrome (MetS). Emerging research has shown that food additives may be implicated in these diseases. However, critics have suggested that some of this research is problematic and may cause unnecessary fear amongst consumers. Here we review the emerging research concerning food additives and their implication in IBD and MetS, and criticisms thereof. To make the review more relevant to the WD, we only included common food additives, selected using supermarket data. Over a dozen common food additives from four categories were identified for their potential role in directly promoting these diseases. A consistent limitation of the research was the use of unrealistic human exposure conditions, such as high doses and modes of administration, as well as a lack of human trials. Another limitation was the absence of studies investigating the potential synergetic effect of consuming multiple food additives, as is common in the WD. Despite the limitations, there is some evidence that common food additives may be contributing to these additives, especially via their dysbiotic effect on the gut microbiota.

Marine polysaccharides for antibiofilm application: A focus on biomedical fields

Microbial pathogens such as bacteria and fungi form biofilms, which represent substantial hurdles in treating human illness owing to their adaptive resistance mechanism to conventional antibiotics. Biofilm may cause persistent infection in a variety of bodily areas, including wounds, oral cavity, and vaginal canal. Using invasive devices such as implants and catheters contributes significantly to developing healthcare-associated infections because they offer an ideal surface for biofilm formation. Marine organisms produce a variety of polysaccharides, which have recently attracted worldwide attention due to their biochemical features, various applications, and advantageous properties such as bioactivity, biodegradability, and biocompatibility. Because of their antimicrobial and antibiofilm features, several polysaccharides such as chitosan, fucoidan, carrageenan, alginate, and hyaluronic acid have been used to treat infected wounds as well as ophthalmic, oral, and vaginal infections. In addition, marine polysaccharides are currently employed as coatings on medical devices and implant materials, alone or in combination with other bioactive substances or nanomaterials, to protect the materials' undertones from microbial contamination. This review discussed the recent advancements in marine polysaccharides and their derivatives as a therapeutic potential against biofilm-associated diseases. The potential obstacles in the scalability of their production, clinical translation, and/or regulatory hurdles have also been discussed.

Carrageenan and insulin resistance in humans: a randomised double-blind cross-over trial

BACKGROUND

The potential impact of specific food additives, common in Western diets, on the risk of developing type 2 diabetes is not well understood. This study focuses on carrageenan, a widely used food additive known to induce insulin resistance and gut inflammation in animal models, and its effects on human health.

METHODS

In a randomised, double-blind, placebo-controlled, cross-over trial conducted at a university hospital metabolic study centre, 20 males (age 27.4 ± 4.3 years, BMI 24.5 ± 2.5 kg/m2) participated. The intervention involved oral intake of carrageenan (250 mg) or placebo in the morning and in the evening and each intervention lasted 2 weeks. The primary outcome measured was insulin sensitivity (using oral glucose tolerance test [OGTT] and hyperinsulinaemic-euglycaemic clamp). Additional end-points included whole body and hepatic insulin sensitivity, MRI-measured brain inflammation and insulin resistance, intestinal permeability (via lactulose-mannitol test and plasma zonulin levels), and gut microbiome composition. Immune-cell activation and pro-inflammatory cytokine release from peripheral blood mononuclear cells were measured.

RESULTS

Overall insulin sensitivity did not show significant differences between the treatments. However, interactions between BMI and treatment were observed (OGTT-based insulin sensitivity index: p=0.04, fasting insulin resistance: p=0.01, hepatic insulin sensitivity index: p=0.04). In overweight participants, carrageenan exposure resulted in lower whole body and hepatic insulin sensitivity, a trend towards increased brain inflammation, and elevated C-reactive protein (CRP) and IL-6 levels compared to placebo. Additionally, carrageenan was associated with increased intestinal permeability. In vitro natural killer (NK-)cell activation and increased pro-inflammatory cytokine release were found after carrageenan exposure in the participant's peripheral blood mononuclear cells.

CONCLUSIONS

These findings suggest that carrageenan, a common food additive, may contribute to insulin resistance and subclinical inflammation in overweight individuals through pro-inflammatory mechanisms in the gut. Further investigation into the long-term health impacts of carrageenan and other food additives is warranted.

TRIAL REGISTRATION

NCT02629705.

AJ, Kurian C, Chakraborty P, Paari KA. Food additives and contaminants in infant foods: a critical review of their health risk, trends and recent developments

The infant food market has expanded rapidly over the past two decades. However, the industry faces significant challenges, including concerns over the health effects of infant food additives and issues with food safety. However, new evidences suggest that certain food additives, such as those used to preserve and transport infant formula to keep it fresh for longer, should be avoided. Science into the effects of additives on human behavior makes up a sizable sector of the additives market. Problems such as hypernatremic dehydration, malnutrition, and obesity in infants are directly linked to faulty formula production. The Food and Drug Administration (FDA) has established the toxicity types and chemical tests necessary for evaluating the safety of food additives and GRAS (Generally Recognized as Safe) compounds. These tests are crucial in understanding the food safety aspects of food additives. The health effects of different types of food additives on infants are discussed in this context. The article gives an outline of various national and global agencies that provides recommendations and standards to gauge the quality of baby food. The immunological responses, allergic reaction pathways and other related health hazards among the infants and young children caused by the food additive are discussed in this article.

Graphical Abstract

Kappa-carrageenan in a pork-based high-fat diet inhibited lipid bioavailability through interactions with pork protein

κ-Carrageenan is a soluble dietary fiber widely used in meat products. Although its regulatory effect on glycolipid metabolism has been reported, the underlying mechanism remains unclear. The present study established a pork diet model for in vitro digestion to study how κ-carrageenan affected its digestive behavior and lipid bioavailability. The results revealed that κ-carrageenan addition to a pork-based high-fat diet reduced the rate of lipolysis and increased the number and size of lipid droplets in an in vitro digestion condition. However, κ-carrageenan did not inhibit lipolysis when lipids and κ-carrageenan were mixed directly or with the addition of pork protein. Furthermore, the pork protein in the diet significantly enhanced the inhibitory effect of κ-carrageenan on lipolysis with decreased proteolysis and raised hydrophobicity of protein hydrolysate. Our findings suggest that κ-carrageenan can inhibit dietary lipid bioavailability by interacting with pork protein in meat products or meat-based diets during digestion and indicate the positive role of carrageenan in the food industry to alleviate the excessive accumulation of lipids in the body.

Marine Polysaccharides Carrageenans Enhance Eryptosis and Alter Lipid Order of Cell Membranes in Erythrocytes

Aim In the current study, hemocompatibility of three major commercially available types of carrageenans (ι, κ and λ) was investigated focusing on eryptosis.

MATERIALS AND METHODS

Carrageenans of ι-, κ- and λ-types were incubated with washed erythrocytes (hematocrit 0.4%) at 0-1-5-10 g/L for either 24 h or 48 h. Incubation was followed by flow cytometry-based quantitative analysis of eryptosis parameters, including cell volume, cell membrane scrambling and reactive oxygen species (ROS) production, lipid peroxidation markers and confocal microscopy-based evaluation of intracellular Ca2+ levels, assessment of lipid order in cell membranes and the glutathione antioxidant system. Confocal microscopy was used to assess carrageenan cellular internalization using rhodamine B isothiocyanate-conjugated carrageenans.

RESULTS

All three types of carrageenans were found to trigger eryptosis. Pro-eryptotic properties were type-dependent and λ-carrageenan had the strongest impact inducing phosphatidylserine membrane asymmetry, changes in cell volume, Ca2+ signaling and oxidative stress characterized by ROS overproduction, activation of lipid peroxidation and severe glutathione system depletion. Eryptosis induction by carrageenans does not require their uptake by erythrocytes. Changes in physicochemical properties of cell membrane were also type-dependent. No carrageenan-induced generation of superoxide and hydroxyl radicals was observed in cell-free milieu.

CONCLUSIONS

Our findings suggest that ι-, κ- and λ-types trigger eryptosis in a type-dependent manner and indicate that carrageenans can be further investigated as potential eryptosis-regulating therapeutic agents.

Carrageenan films as promising mucoadhesive ocular drug delivery systems

Polymer mucoadhesive films being developed for use in ophthalmology represent a new tool for drug delivery and are considered an alternative to traditional dosage forms. Due to their mucoadhesive properties, carrageenans (CRGs) are widely used in various forms for drug delivery. In this study, films based on CRGs of various structural types (κ/β, κ, x, and λ) for use in ophthalmology were studied. The films were loaded with the active substance echinochrome (ECH), a sea urchin pigment used in ophthalmology. Spectral data showed that ECH remained stable after its incorporation into the CRG films and did not oxidize for at least six months. Hydrophilic CRG films with a thickness of 10-12 µm were characterized in terms of their swelling and mucoadhesive properties. The rheological properties of solutions formed after film dissolution in artificial tears were also assessed. κ- and κ/β-CRG films with ECH exhibited pseudoplastic behavior after rehydrating films with an artificial tear solution. The CRG-loaded films had different swelling characteristics depending on the structure of the CRG used. The films based on highly sulfated CRGs dissolved in artificial tears, while the films of low-sulfated κ/β-CRG exhibited limited swelling. All studied ECH-loaded films exhibited mucoadhesive properties, which were evaluated by a texture analyzer using mucous tissue of the small intestine of the pig as a model. There was a slight prolongation of ECH release from CRG films in artificial tears. The effect of CRG/ECH on the epithelial cell lines of the outer shell of the human eye was investigated. At low concentrations, ECH in the composition of the CRG/ECH complex had no cytotoxic effect on corneal epithelial and conjunctival human cells. The use of ECH-containing films can prevent the drug from being immediately washed away by tears and help to retain it by increasing viscosity and having mucoadhesive properties.

Methylation-GC-MS/FID-Based Glycosidic Linkage Analysis of Unfractionated Polysaccharides in Red Seaweeds

Glycosidic linkage analysis was conducted on the unfractionated polysaccharides in alcohol-insoluble residues (AIRs) prepared from six red seaweeds (Gracilariopsis sp., Prionitis sp., Mastocarpus papillatus, Callophyllis sp., Mazzaella splendens, and Palmaria palmata) using GC-MS/FID analysis of partially methylated alditol acetates (PMAAs). The cell walls of P. palmata primarily contained mixed-linkage xylans and small amounts of sulfated galactans and cellulose. In contrast, the unfractionated polysaccharides of the other five species were rich in galactans displaying diverse 3,6-anhydro-galactose and galactose linkages with varied sulfation patterns. Different levels of cellulose were also observed. This glycosidic linkage method offers advantages for cellulose analysis over traditional monosaccharide analysis that is known for underrepresenting glucose in crystalline cellulose. Relative linkage compositions calculated from GC-MS and GC-FID measurements showed that anhydro sugar linkages generated more responses in the latter detection method. This improved linkage workflow presents a useful tool for studying polysaccharide structural variations across red seaweed species. Furthermore, for the first time, relative linkage compositions from GC-MS and GC-FID measurements, along with normalized FID and total ion current (TIC) chromatograms without peak assignments, were analyzed using principal component analysis (PCA) as a proof-of-concept demonstration of the technique's potential to differentiate various red seaweed species.

Carrageenan oligosaccharide alleviates intestinal damage via gut microflora through activating IMD/relish pathway in female Drosophila melanogaster

Recent evidence suggests the anti-inflammatory effect of carrageenan oligosaccharides (COS). The effects of COS on intestinal injury induced by 0.6% sodium dodecyl sulfate (SDS) and the molecular mechanisms involved were investigated in this study. 0.625, 1.25, and 2.5 mg/mL COS in diet had no toxic effect in flies, and they could all prolong SDS-treated female flies' survival rate. 1.25 mg/mL COS prevented the development of inflammation by improving the intestinal barrier integrity and maintaining the intestinal morphology stability, inhibited the proliferation of intestine stem cells (ISCs), and the production of lysosomes induced by SDS, accompanied by a decrease in the expression of autophagy-related genes. Moreover, COS decreased the active oxygen species (ROS) content in gut and increased the antioxidant activity in SDS-induced female flies, while COS still played a role in increasing survival rate and decreasing intestinal leakage in CncC-RNAi flies. The improvement of anti-inflammation capacity may be associated with the regulation of intestinal microflora with COS supplementation for Drosophila melanogaster. COS changed the gut microbiota composition, and COS had no effect on germ-free (GF) flies. It is highlighted that COS could not work in Relish-RNAi flies, indicating relish is required for COS to perform beneficial effects. These results provide insights into the study of gut microbiota interacting with COS to modulate intestinal inflammation in specific hosts.

Evidence and hypotheses on adverse effects of the food additives carrageenan (E 407)/processed Eucheuma seaweed (E 407a) and carboxymethylcellulose (E 466) on the intestines: a scoping review

This scoping review provides an overview of publications reporting adverse effects on the intestines of the food additives carrageenan (CGN) (E 407)/processed Eucheuma seaweed (PES) (E 407a) and carboxymethylcellulose (CMC) (E 466). It includes evidence from human, experimental mammal and in vitro research publications, and other evidence. The databases Medline, Embase, Scopus, Web of Science Core Collection, Cochrane Database of Systematic Reviews and Epistemonikos were searched without time limits, in addition to grey literature. The publications retrieved were screened against predefined criteria. From two literature searches, 2572 records were screened, of which 224 records were included, as well as 38 records from grey literature, making a total of 262 included publications, 196 on CGN and 101 on CMC. These publications were coded and analyzed in Eppi-Reviewer and data gaps presented in interactive maps. For CGN, five, 69 and 33 research publications on humans, experimental mammals and in vitro experiments were found, further separated as degraded or native (non-degraded) CGN. For CMC, three human, 20 animal and 14 in vitro research publications were obtained. The most studied adverse effects on the intestines were for both additives inflammation, the gut microbiome, including fermentation, intestinal permeability, and cancer and metabolic effects, and immune effects for CGN. Further studies should focus on native CGN, in the form and molecular weight used as food additive. For both additives, randomized controlled trials of sufficient power and with realistic dietary exposure levels of single additives, performed in persons of all ages, including potentially vulnerable groups, are needed.

Current and emerging applications of carrageenan in the food industry

Carrageenan, a polysaccharide derived from red algae, has a long history of use as a food additive in food. Carrageenan comes in three classes, κ-, ι-, and λ-carrageenan, with different properties attributed to their organosulfate substitution levels, and their interactions with other food components give rise to properties such as water holding, thickening, gelling, and stabilizing. Over the years, carrageenan has been used in wide variety of food products such as meat, dairy, and flour-based products, and their mechanisms and functions in these matrices have also been studied. With the emergence of novel food technologies, carrageenan's potential applications have been extensively explored alongside, including encapsulation, edible films/coatings, plant-based analogs, and 3D/4D printing. As the food technology evolves, the required functions of food ingredients have changed, and carrageenan is being investigated for its role in these new areas. However, there are many similarities in the use of carrageenan in both classic and emerging applications, and understanding the underlying principles of carrageenan will lead to a proper use of carrageenan in emerging food products. This review focuses on the potential of carrageenan as a food ingredient in these emerging technologies mainly based on papers published within the past five years, highlighting its functions and applications to better understand its role in food products.

Origins and Evolution of Novel Bacteroides in Captive Apes

Bacterial strains evolve in response to the gut environment of their hosts, with genomic changes that influence their interactions with hosts as well as with other members of the gut community. Great apes in captivity have acquired strains of Bacteroides xylanisolvens, which are common within gut microbiome of humans but not typically found other apes, thereby enabling characterization of strain evolution following colonization. Here, we isolate, sequence and reconstruct the history of gene gain and loss events in numerous captive-ape-associated strains since their divergence from their closest human-associated strains. We show that multiple captive-ape-associated B. xylanisolvens lineages have independently acquired gene complexes that encode functions related to host mucin metabolism. Our results support the finding of high genome fluidity in Bacteroides, in that several strains, in moving from humans to captive apes, have rapidly gained large genomic regions that augment metabolic properties not previously present in their relatives.

Development and characterization of crosslinked k-carrageenan/sericin blend with covalent agents or thermal crosslink for indomethacin extended release

Modified release of multiparticulate pharmaceutical forms is a key therapeutic strategy to reduce side effects and toxicity caused by high and repeated doses of immediate-release oral drugs. This research focused on the encapsulation of indomethacin (IND) in the crosslinked k-Car/Ser polymeric matrix by covalent and thermal methods to evaluate drug delivery modulation and properties of the crosslinked blend. Therefore, the entrapment efficiency (EE %), drug loading (DL %) and physicochemical properties of the particles were investigated. The particles presented a spherical shape and a rough surface with a mean diameter of 1.38-2.15 mm (CCA) and 1.56-1.86 mm (thermal crosslink). FTIR investigation indicated the presence of IDM in the particles and X-ray pattern showed the maintenance of crystallinity of IDM. The in vitro release in acidic medium (pH 1.2) and phosphate buffer saline solution (pH 6.8) was 1.23-6.81 % and 81-100 %, respectively. Considering the results, the formulations remained stable after 6 months. The Weibull equation was adequately fitted for all formulations and a diffusion mechanism, swelling and relaxation of chain were observed. IDM-loaded k-carrageenan/sericin/CMC increases cell viability (> 75 % for neutral red and > 81 % for MTT). Finally, all formulations present gastro-resistance, pH response and altered release and have the potential to be used as drug delivery careers.

Influence of food emulsifiers on cellular function and inflammation, a preliminary study

Emulsifiers are extensively used as food additives and their consumption is increasing in Western countries. However, so far only few studies examined their potential effects on intestinal cellular functions and gut inflammation. The aim of this preliminary analysis was to study the emulsifiers and their concentrations capable of causing cellular damage compared to extra virgin olive oil (EVOO). We tested two commonly used emulsifiers (EMI, EMII) and EVOO on Caco-2 cells, derived from a colon carcinoma and widely used as a model of the intestinal inflammation. The diphenyltetrazolium bromide test MTT and clonogenic assay were used to study the effect of emulsifiers on cell viability. Cell migration was determined by the wound-healing assay. The inflammation was studied by measuring the levels of interleukin 6 (IL-6) and monocyte chemoattractant protein-1/C-C motif chemokine ligand 2 (CCL2), multifunctional cytokines with a major role in the acute-phase response. Furthermore, we analyzed the effect of conditioned media of Caco-2 cells treated with EMs on macrophages activation. In conclusion, our preliminary data provide evidence that EMs increase the proliferation and migration rate of Caco-2 cells. Moreover, Caco-2 cells treated with EMs enhance the IL-6 and CCL2 release and activated macrophages, supporting their role as proinflammatory molecules.

Biochemical characterization and elucidation of the action mode of a GH16 family κ-carrageenase for efficient preparation of carrageenan oligosaccharides

κ-Carrageenan oligosaccharides have a variety of biological activities. Degradation of κ-carrageenan by κ-carrageenase leads to degradation products with different degrees of polymerization (DPs). A novel gene (CecgkA) encoding a new κ-carrageenase was cloned from Colwellia echini and heterologously expressed in Escherichia coli BL21 (DE3). The enzyme is 1104 bp in length, encodes 367 amino acid residues and has a molecular weight of 41.30 kDa. Multiple alignment analysis showed that CeCgkA belongs to the glycoside hydrolase (GH16) family and has the highest homology with the κ-carrageenase of Rhodopirellula maiorica SM1, with 58% homology. The CeCgkA showed maximum activity (453.15 U/mg) at pH 8.0 and 35 °C. Determination of biochemical properties showed that CeCgkA was a thermal recovery enzyme, and 51.6% of the initial enzyme activity was recovered by immediately placing the sample at 35 °C for 60 min after enzymatic inactivation by boiling for 10 min. K⁺, Na⁺, and EDTA had an activating effect on the enzyme activity, while Ni²⁺, Cu²⁺, and Zn²⁺ inhibited the activity of the enzyme. In addition, TLC and ESI-MS analysis showed that the maximum recognition unit of CecgkA was decasaccharide and that the main degradation products were disaccharides, tetrasaccharides and hexasaccharides, indicating that the enzyme is an endo-type carrageenase.

Physicochemical Properties and Antiherpetic Activity of κ-Carrageenan Complex with Chitosan

Nanoparticles formation is one of the ways to modulate the physicochemical properties and enhance the activity of original polysaccharides. For this purpose, based on the polysaccharide of red algae, κ-carrageenan (κ-CRG), it polyelectrolyte complex (PEC), with chitosan, were obtained. The complex formation was confirmed by ultracentrifugation in a Percoll gradient, with dynamic light scattering. According to electron microscopy and DLS, PEC is dense spherical particles with sizes in the range of 150-250 nm. A decrease in the polydispersity of the initial CRG was detected after the PEC formation. Simultaneous exposure of Vero cells with the studied compounds and herpes simplex virus type 1 (HSV-1) showed that the PEC exhibited significant antiviral activity, effectively inhibiting the early stages of virus-cell interaction. A two-fold increase in the antiherpetic activity (selective index) of PEC compared to κ-CRG was shown, which may be due to a change in the physicochemical characteristics of κ-CRG in PEC.

Biological activity of algal derived carrageenan: A comprehensive review in light of human health and disease

Carrageenans are a family of natural linear sulfated polysaccharides derived from red seaweeds and used as a common food additive. Carrageenan's properties, impact on health, and aesthetic benefits have all been studied for a long time; however, the mechanisms are still unclear. In pharmaceutical aspects, carrageenan displayed potential antioxidant and immunomodulatory properties in both in vivo and in vitro action. It also contributes to potential disease-preventive activities through dynamic modulation of important intracellular signaling pathways, regulation of ROS buildup, and preservation of major cell survival and death processes which leads to potential drug development. Furthermore, the chemical synthesis of the current bioactive medicine with confirmational rearrangement may increase availability and bioactivity needs diligent examination. In this review, we give an up-to-date overview of recent research on Carrageenan with reference to health and therapeutic advantages. In addition, we have focused on structural conformation and its primary strategic deployment in disease prevention, as well as the mechanistic investigation of how it functions to combat various disease-preventive employed for future therapeutic interventions. This review may get new insights into the possible novel role of carrageenan and open up a novel disease-preventive mechanism and enhance human health.

κ-Selenocarrageenan Oligosaccharides Prepared by Deep-Sea Enzyme Alleviate Inflammatory Responses and Modulate Gut Microbiota in Ulcerative Colitis Mice

κ-Selenocarrageenan (KSC) is an organic selenium (Se) polysaccharide. There has been no report of an enzyme that can degrade κ-selenocarrageenan to κ-selenocarrageenan oligosaccharides (KSCOs). This study explored an enzyme, κ-selenocarrageenase (SeCar), from deep-sea bacteria and produced heterologously in Escherichia coli, which degraded KSC to KSCOs. Chemical and spectroscopic analyses demonstrated that purified KSCOs in hydrolysates were composed mainly of selenium-galactobiose. Organic selenium foods through dietary supplementation could help regulate inflammatory bowel diseases (IBD). This study discussed the effects of KSCOs on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in C57BL/6 mice. The results showed that KSCOs alleviated the symptoms of UC and suppressed colonic inflammation by reducing the activity of myeloperoxidase (MPO) and regulating the unbalanced secretion of inflammatory cytokines (tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-10). Furthermore, KSCOs treatment regulated the composition of gut microbiota, enriched the genera Bifidobacterium, Lachnospiraceae_NK4A136_group and Ruminococcus and inhibited Dubosiella, Turicibacter and Romboutsia. These findings proved that KSCOs obtained by enzymatic degradation could be utilized to prevent or treat UC.

How does carrageenan cause colitis? A review

Carrageenan is a common additive, but mounting studies have reported that it may cause or aggravate inflammation in the intestines. The safety of carrageenan remains controversial and its inflammatory mechanisms are unclear. In this review, the pathogenesis of colitis by carrageenans was discussed. We analyzed the pathogenesis of inflammatory bowel disease, followed that line of thought, the existing evidence of carrageenans causing colitis in cellular and animal models was summarized to draw its colitis pathogenesis. Two pathways were described including: 1) carrageenan changed the composition of intestinal microbiota, especially Akkermansia muciniphila, which destroyed the mucosal barrier and triggered the inflammatory immune response; and 2) carrageenan directly contacted with receptors on epithelial cells and activated the NF-κB inflammatory pathway. This review aim to provide guidance for exploring the treatment of colitis caused by carrageenan, and safe processing and utilization of carrageenan in food industry, which is worthy of study in the future.

Effect of physiological pH on the molecular characteristics, rheological behavior, and molecular dynamics of κ-carrageenan/casein

Introduction

During gastrointestinal digestion, κ-carrageenan (κ-CGN) undergoes physicochemical changes, which associated with the risk of colitis.

Methods

To understand the effect of physiological pH on the conformational transition and binding stability of κ-CGN and κ-carrageenan/casein (κ-CC), we conducted experiments at pH 3.0 (gastric environment) and pH 7.0 (intestinal environment). We evaluated zeta potential, free sulfate group content, Fourier transform infrared spectroscopy, thermodynamic properties, microstructure, and molecular mechanism.

Results and Discussion

Our results revealed that the helical conformation of κ-CGN and κ-CC were more ordered and stable, and sulfate group exposure both lower in the intestinal environment (pH 7.0). However, in gastric environment (pH 3.0), the charge density of κ-CGN decreased, accompanied by random curling conformation and free sulfate group content increased. In contrast, the intermolecular interactions between κ-CGN and casein increased in gastric acid environments due to casein flocculation and secondary structure folding, and significantly reduced the exposure of free sulfate groups of κ-CGN. Our research results provide an important theoretical basis for elucidating the molecular mechanism and structure-activity relationship of κ-CGN under casein matrix to protect the mucosal barrier and inhibit colitis, and are of great significance for guiding and expanding the safe application of κ-CGN, thus assisting food nutrition to be absorbed.

Marine macroalgae polysaccharides-based nanomaterials: an overview with respect to nanoscience applications

Background

Exploration of marine macroalgae poly-saccharide-based nanomaterials is emerging in the nanotechnology field, such as wound dressing, water treatment, environmental engineering, biosensor, and food technology.

Main body

In this article, the current innovation and encroachments of marine macroalgae polysaccharide-based nanoparticles (NPs), and their promising opportunities, for future prospect in different industries are briefly reviewed. The extraction and advancement of various natural sources from marine polysaccharides, including carrageenan, agarose, fucoidan, and ulvan, are highlighted in order to provide a wide range of impacts on the nanofood technology. Further, seaweed or marine macroalgae is an unexploited natural source of polysaccharides, which involves numerous different phytonutrients in the outermost layer of the cell and is rich in sulphated polysaccharides (SP), SP-based nanomaterial which has an enhanced potential value in the nanotechnology field.

Conclusion

At the end of this article, the promising prospect of SP-based NPs and their applications in the food sector is briefly addressed.

The Anti-Inflammatory Effect of Carrageenan/Echinochrom Complex at Experimental Endotoxemia

The anti-inflammatory effects of the CRG/Ech complex in LPS-induced endotoxemia were investigated in vivo in mice and in vitro in LPS-stimulated RAW 264.7 cells and peritoneal macrophages. The results indicated that the CRG/Ech complex suppressed the LPS-induced inflammatory response by reducing the production of ROS and NO in the macrophages. Furthermore, the in vivo experiment indicated that the CRG/Ech complex minimized disorders of the physiological and metabolic processes in mice subjected to LPS intoxication and reduced the levels of proinflammatory cytokines in the mouse serum. The preventive administration of the CRG/Ech complex to mice prevented endotoxin-induced damage in the mouse model of endotoxemia, increased the mice’s resistance to LPS, and prevented increases in the levels of proinflammatory cytokines (TNFα). In this work, we showed by the molecular docking that Ech interacted with carrageenan, and that H-donor and H-acceptor bonds are involved in the formation of the complex.

Biochemical Characterization of a Cold-Adapted λ-Carrageenase OUC-CglA from Maribacter vaceletii: An Efficient Tool for λ-Carrageenan Degradation

λ-Carrageenase with high activity is an effective and environmentally friendly tool enzyme for the preparation of λ-carrageenan oligosaccharides with various biological activities. Herein, a novel GH150 (glycoside hydrolases family 150) λ-carrageenase OUC-CglA from Maribacter vaceletii was heterologously expressed, purified, and characterized. The recombinant OUC-CglA performs strict selectivity toward λ-carrageenan with a specific activity of 418.7 U/mg under its optimal reaction conditions of 20 °C and pH 7.0. Additionally, OUC-CglA is a typical cold-adapted λ-carrageenase because it unfolds 90% and 63% of its maximum activity at 15 and 10 °C, respectively. The hydrolysis process suggests that OUC-CglA is an endotype λ-carrageenase with the final products consisting of λ-neocarrabiose, λ-neocarratetraose, λ-neocarrahexaose, and other long-chain λ-neocarrageenan oligosaccharides. As a result, high activity, cold-adaptation, and principal products of OUC-CglA make it a potential biocatalyst for the effective preparation of λ-carrageenan oligosaccharides.

A novel multifunctional Salecan/κ-carrageenan composite hydrogel with anti-freezing properties: Advanced rheology, thermal analysis and model fitting

The multifunctional hydrogels (HGs) have attracted intensive concern in biomedicine, food, and flexible devices. Nevertheless, chemically crosslinked synthetic HGs are commonly under specific restrictions because of their possible biotoxicity. This study focuses on the employment of physical approaches to prepare novel Salecan/κ-carrageenan composites HGs (CHGs) without changing their basic structures. Comprehensive rheological and thermal studies have been performed to investigate their distinctive properties. The data obtained from the tests and model fitting confirmed that the highest activation energy of CHGs was 172,142.2 J/mol, and the maximum equilibrium creep compliance was 0.0085 1/Pa. The sample recovery rate could reach 92.6%, while the anti-freezing temperature can be as low as -20 °C. It is the first report focusing on novel CHGs made from Salecan and κ-carrageenan with ideal anti-freezing ability, enhanced thermostability, good injectability, self-recovery, and other rheological properties that will provide effective support for various future applications.

Ultrasound Viscoelastic Properties of Biomass Polysaccharide Hydrogels as Evaluated by Rheometer Equipped with Sono-Device

A viscoelastic rheometer was equipped with a sono-device and a water bath to enable measurement of storage moduli G′ and loss moduli G″ of biomass polysaccharide hydrogels such as Kanten agarose, κ-carrageenan, and konjac glucomannan under ultrasound (US) exposure. The action of low power of 43 kHz US on their hydrogels significantly decreased G′ of Kanten agarose and carrageenan after a few seconds of US exposure 0.1% strain. When US with 20 W output power was exposed under mechanical strain at 0.1%, lower values were obtained cyclically for 3 min US intervals. The values then reverted to the original moduli values when US was stopped in cases of Kanten agarose and carrageenan hydrogels. As G″ values were increased during US operation, the anhydro-L-galactose segments in their hydrogels were unable to relax the external US forces within the gel sufficiently, thereby leading to gel structure collapse at a higher strain percentage. These results suggest that US exposure induced deformational change in the hydrogel structure formed by hydrogen-bonded cross-links. However, US deformation was less in the case of deacetylated cross-linkage in konjac glucomannan hydrogel.

Algal polysaccharides and derivatives as potential therapeutics for obesity and related metabolic diseases

The potential and challenges of algal polysaccharides and their derivatives as potential therapeutic agents for obesity and its related metabolic diseases.

Hepatic antioxidant activity, immunomodulation, and pro-anti-inflammatory cytokines manipulation of κ-carrageenan (κ-CGN) in cobia, Rachycentron canadum against Lactococcus garvieae

The effects of dietary k-Carrageenan (k-CGN) at 10, 20, and 30 g kg-1 on growth rate, hemato-biochemical indices, innate-adaptive parameters and modification of pro- and/or anti-inflammatory cytokines and chemokines pathway in cobia, Rachycentron canadum against Lactococcus garvieae is reported. The weight gain (WG) increased substantially (P < 0.05) in all k-CGN treated groups; the specific growth rate (SGR) was significant in healthy uninfected normal (HuN) and L. garvieae challenged (LaC) groups fed with 20 g kg-1k-CGN diet on 45 and 60 days. The white blood cell (WBC) counts, total protein (TP) level, total anti-oxidant (T-AOC), catalase (CAT), and glutathione (GSH) activities increased significantly when fed with 20 g and 30 g kg-1k-CG diets on 45th and 60th day. The immunological parameters such as phagocytic (PC) index and the activity of phagocytic (PC), respiratory burst (RB), superoxide dismutase (SOD), alternate complement pathway (ACH50), and lysozyme (LZM) were significantly enhanced with all k-CG diets in 45 and 60 days of treatment. No cumulative mortality (CM) in HuN group fed by control or any k-CGN diets. CM was 5% in LaC group fed with 20 g kg-1k-CGN diet whereas in LaC groups fed with 10 g and 30 g kg-1k-CGN diets the CM was 10%. The interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNFα) pro-inflammatory cytokines mRNA transcripts were one-fold high (P < 0.05) in both HuN and LaC group fed all k-CGN enriched diets on 45 and 60 days. Similarly, IL-18 and TLR2 mRNA was one-fold high expression in both groups fed the 20 g and 30 g kg-1k-CGN enriched diets on 45 or 60 days. Interferon gamma (IFNγ) and interferon regulatory factor 3/7 (IRF3/IRF7) mRNA transcripts did not change with any diet. IL-6, IL-10, and IL-11 mRNA were one-fold high expressions in both groups fed the 20 g and 30 g kg-1k-CGN enriched diets on 45 and 60 days. However, the expression of CC1, CC3, and CCR9 pro-inflammatory chemokines mRNA did not vary with any control or k-CGN enriched diets. The results indicate that diet enriched with k-CGN at 20 g kg-1 significantly influences the growth, antioxidant and innate-adaptive immune performance, and pro-anti-inflammatory cytokines and chemokines regulation in cobia against L. garvieae.

Mechanical Disintegration and Particle Size Sieving of Chondrus crispus (Irish Moss) Gametophytes and Their Effect on Carrageenan and Phycoerythrin Extraction

To better understand the migration properties of hybrid carrageenan from the seaweed tissue during carrageenan extraction, the effect of increasing the seaweed surface area by the mechanical disintegration of gametophyte Chondrus crispus chips was studied under various temperature and time extraction conditions. Dried Chondrus crispus seaweed chips were milled by a rotor beater mill and classified into eight different size fractions by sieving with varying mesh sizes from 50 to 2000 μm. During extraction at 22 °C, the red color of the filtrate increased significantly with the decreasing particle size of the fraction, correlating with the increasing phycoerythrin concentration (from 0.26 mg PE/g dry seaweed in the >2000 μm size fraction to 2.30 mg PE/g dry seaweed in the <50 μm size fraction). On the other hand, under the same extraction conditions, only a small increase in carrageenan precipitate was obtained with the decreasing size fractions (from no recovery in the >2000 μm size fraction to 2.1 ± 0.1 g/kg filtrate in the <50 μm size fraction). This yield was significantly lower than the ones from extractions at 45 °C (5.4 ± 0.1 g/kg) or at 90 °C (9.9 ± 2.1 g/kg) for the same particle size and time conditions. It could be concluded that hybrid carrageenan extraction is not surface area dependent, while phycoerythrin is. Therefore, it seems that phycoerythrin and carrageenan extraction follow different mechanisms. This creates potential for the selective extraction of each of those two compounds.

The mechanism exploration of the non-colonic toxicity and obesity inhibition of food-grade κ-carrageenan by transcriptome

Previous study has suggested the colonic nontoxicity and obesity inhibition of food-grade κ-carrageenan in obese mice. Further study using transcriptome is important to provide further understanding on the gene expressions of inflammation and obesity. Here, the obese mice without any treatment (HFD) or with 5% food-grade κ-carrageenan diet intervention (H5%) were used to perform colonic transcriptome sequencing. The results showed that genes involved in the inflammatory pathways or tight junction protein encoding were not significantly dysregulated by 5% carrageenan. However, the expression of lipid metabolism genes meaningfully changed as evidenced by the decreased gene levels of adipocytokines, lipogenesis, lipid absorption and transport, and the increased adipolysis and oxidation. In addition, the carrageenan metabolism experiments by toluidine blue (TB) staining of colon and high-performance size exclusion chromatography (HPSEC) of feces supernatant showed that the food-grade κ-carrageenan was not absorbed or significantly degraded in the digestive tract of obese mice. Hence, the fact that food-grade κ-carrageenan was not significantly metabolized by the organism and did not cause obvious dysregulation of colonic inflammatory genes provided evidences for its noncolonic toxicity in obese mice. An anti-obesity potential of food-grade κ-carrageenan was probably mediated by the regulation of lipids metabolism-related genes.

Disposable Food Packaging and Serving Materials-Trends and Biodegradability

Food is an integral part of everyone’s life. Disposable food serving utensils and tableware are a very convenient solution, especially when the possibility of the use of traditional dishes and cutlery is limited (e.g., takeaway meals). As a result, a whole range of products is available on the market: plates, trays, spoons, forks, knives, cups, straws, and more. Both the form of the product (adapted to the distribution and sales system) as well as its ecological aspect (biodegradability and life cycle) should be of interest to producers and consumers, especially considering the clearly growing trend of “eco-awareness”. This is particularly important in the case of single-use products. The aim of the study was to present the current trends regarding disposable utensils intended for contact with food in the context of their biodegradability. This paper has summarized not only conventional polymers but also their modern alternatives gaining the attention of manufacturers and consumers of single-use products (SUPs).

Experimental Evaluation of Food-Grade Semi-Refined Carrageenan Toxicity

The safety of food additives E407 and E407a has raised concerns in the scientific community. Thus, this study aims to assess the local and systemic toxic effects of the common food additive E407a in rats orally exposed to it for two weeks. Complex evaluations of the effects of semi-refined carrageenan (E407a) on rats upon oral exposure were performed. Local effects of E407a on the intestine were analyzed using routine histological stains and CD68 immunostaining. Furthermore, circulating levels of inflammatory markers were assessed. A fluorescent probe O1O (2- (2'-OH-phenyl)-5-phenyl-1,3-oxazole) was used for evaluating the state of leukocyte cell membranes. Cell death modes of leukocytes were analyzed by flow cytometry using Annexin V and 7-aminoactinomycin D staining. Oral administration of the common food additive E407a was found to be associated with altered small and large intestinal morphology, infiltration of the lamina propria in the small intestine with macrophages (CD68+ cells), high systemic levels of inflammation markers, and changes in the lipid order of the phospholipid bilayer in the cell membranes of leukocytes, alongside the activation of their apoptosis. Our findings suggest that oral exposure to E407a through rats results in the development of intestinal inflammation.

Efficacy of a Nasal Spray Containing Iota-Carrageenan in the Postexposure Prophylaxis of COVID-19 in Hospital Personnel Dedicated to Patients Care with COVID-19 Disease

BACKGROUND

Iota-Carrageenan (I-C) is a sulfate polysaccharide synthesized by red algae, with demonstrated antiviral activity and clinical efficacy as nasal spray in the treatment of common cold. In vitro, I-C inhibits SARS-CoV-2 infection in cell culture.

RESEARCH QUESTION

Can a nasal spray with Iota-Carrageenan be useful in the prophylaxis of COVID-19 in health care workers managing patients with COVID-19 disease?

STUDY DESIGN AND METHODS

This is a pilot pragmatic multicenter, randomized, double-blind, placebo-controlled study assessing the use of a nasal spray containing I-C in the prophylaxis of COVID-19 in hospital personnel dedicated to care of COVID-19 patients. Clinically healthy physicians, nurses, kinesiologists and other health care providers managing patients hospitalized for COVID-19 were assigned in a 1:1 ratio to receive four daily doses of I-C spray or placebo for 21 days. The primary end point was clinical COVID-19, as confirmed by reverse transcriptase polymerase chain reaction testing, over a period of 21 days. The trial is registered at ClinicalTrials.gov (NCT04521322).

RESULTS

A total of 394 individuals were randomly assigned to receive I-C or placebo. Both treatment groups had similar baseline characteristics. The incidence of COVID-19 differs significantly between subjects receiving the nasal spray with I-C (2 of 196 [1.0%]) and those receiving placebo (10 of 198 [5.0%]). Relative risk reduction: 79.8% (95% CI 5.3 to 95.4; p=0.03). Absolute risk reduction: 4% (95% CI 0.6 to 7.4).

INTERPRETATION

In this pilot study a nasal spray with I-C showed significant efficacy in preventing COVID-19 in health care workers managing patients with COVID-19 disease.

CLINICAL TRIALS REGISTRATION

NCT04521322.

The Role of Carrageenan in Inflammatory Bowel Diseases and Allergic Reactions: Where Do We Stand?

Carrageenan (CGN) is a high molecular weight polysaccharide extracted from red seaweeds, composed of D-galactose residues linked in β-1,4 and α-1,3 galactose-galactose bond, widely used as a food additive in processed foods for its properties as a thickener, gelling agent, emulsifier, and stabilizer. In recent years, with the spread of the Western diet (WD), its consumption has increased. Nonetheless, there is a debate on its safety. CGN is extensively used as an inflammatory and adjuvant agent in vitro and in animal experimental models for the investigation of immune processes or to assess the activity of anti-inflammatory drugs. CGN can activate the innate immune pathways of inflammation, alter the gut microbiota composition and the thickness of the mucus barrier. Clinical evidence suggests that CGN is involved in the pathogenesis and clinical management of inflammatory bowel diseases (IBD), indeed food-exclusion diets can be an effective therapy for disease remission. Moreover, specific IgE to the oligosaccharide α-Gal has been associated with allergic reactions commonly referred to as the "α-Gal syndrome". This review aims to discuss the role of carrageenan in inflammatory bowel diseases and allergic reactions following the current evidence. Furthermore, as no definitive data are available on the safety and the effects of CGN, we suggest gaps to be filled and advise to limit the human exposure to CGN by reducing the consumption of ultra-processed foods.

Food additive E407a stimulates eryptosis in a dose-dependent manner

BACKGROUND

Concerns about the biosafety of the common food additive E407a have been raised. It has been demonstrated to induce intestinal inflammation, accompanied by activation of apoptosis, upon oral exposure. Thus, it is of interest to investigate how E407a affects eryptosis, a suicidal cell death mode of red blood cells.

OBJECTIVE

To evaluate the effects of semi-refined carrageenan (E407a) on eryptosis.

METHODS

Flow cytometry was employed to assess eryptosis in blood exposed to various concentrations of E407a (0 g/L, 1 g/L, 5 g/L, and 10 g/L) during incubation for 24 h by analyzing phosphatidylserine externalization in erythrocytes using annexin V staining and via evaluating reactive oxygen species (ROS) generation using 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA). In addition, the eryptosis indices mentioned above were determined in rats orally administered E407a at a dose of 140 mg/kg weight for 2 weeks. Confocal scanning laser microscopy was performed to visualize cell membrane scrambling.

RESULTS

Oral intake of E407a for 2 weeks by rats was not associated with membrane scrambling in erythrocytes. However, ROS overproduction was observed. Meanwhile, incubation of blood with various concentrations of semi-refined carrageenan resulted in a dose-dependent promotion of eryptosis, evidenced by the enhanced percentage of annexin V-positive erythrocytes and higher mean fluorescence intensity (MFI) values of annexin V-FITC in all erythrocytes. The highest concentration of E407a promotes a statistically significant increase in ROS generation in erythrocytes, suggesting the role of ROS-mediated induction of eryptosis in this case.

CONCLUSION

Incubation of blood with the food additive E407a leads to the activation of eryptosis in a dose-dependent manner. ROS-mediated mechanisms are partially responsible for E407a-induced eryptosis.

Carrageenan nasal spray may double the rate of recovery from coronavirus and influenza virus infections: Re-analysis of randomized trial data

In this individual patient data meta-analysis we examined datasets of two randomized placebo-controlled trials which investigated the effect of nasal carrageenan separately on children and adults. In both trials, iota-carrageenan was administered nasally three times per day for 7 days for patients with the common cold and follow-up lasted for 21 days. We used Cox regression to estimate the effect of carrageenan on recovery rate. We also used quantile regression to calculate the effect of carrageenan on colds of differing lengths. Nasal carrageenan increased the recovery rate from all colds by 54% (95% CI 15%-105%; p = .003). The increase in recovery rate was 139% for coronavirus infections, 119% for influenza A infections, and 70% for rhinovirus infections. The mean duration of all colds in the placebo groups of the first four quintiles were 4.0, 6.8, 8.8, and 13.7 days, respectively. The fifth quintile contained patients with censored data. The 13.7-day colds were shortened by 3.8 days (28% reduction), and 8.8-day colds by 1.3 days (15% reduction). Carrageenan had no meaningful effect on shorter colds. In the placebo group, 21 patients had colds lasting over 20 days, compared with six patients in the carrageenan group, which corresponds to a 71% (p = .003) reduction in the risk of longer colds. Given that carrageenan has an effect on diverse virus groups, and effects at the clinical level on two old coronaviruses, it seems plausible that carrageenan may have an effect on COVID-19. Further research on nasal iota-carrageenan is warranted.

Clean Label Trade-Offs: A Case Study of Plain Yogurt

Consumer demand for clean label has risen in recent years. However, clean label foods with simple and minimalistic ingredient lists are often expensive to produce and/or may possess less desirable sensory qualities. Accordingly, understanding consumer preferences regarding the clean label trend would be of great interest to the food industry. Here we investigate how ingredient lists and associated sensory quality descriptions may influence consumer preferences using a hypothetical choice experiment. In particular, we test the impacts of four common stabilizers (carrageenan, corn starch, milk protein concentrate, and pectin) and textural characteristics on preferences and willingness to pay for plain yogurt. A total of 250 yogurt consumers participated in the study. The results of a mixed logit analysis suggest that clean labeling significantly increases the likelihood of consumer choice, while poor texture reduces consumer choice. More importantly, the negative impact of poor texture seems to be less significant for clean label yogurts compared to that for yogurts with longer ingredient lists. Among all stabilizers, corn starch in particular has a significant negative impact on consumer choice. The estimated average consumer willingness to pay for clean labels is between $2.54 and $3.53 for 32 oz yogurt formulations. Furthermore, clean labels minimize the negative impact of textural defects with consumers willing to pay an estimated premium of $1.61 for the family size yogurt with a simple ingredient list. Results of latent class modeling reveal two classes of consumers with similar patterns of demand who prefer clean labels and, on average, would rather purchase a yogurt with a textural defect than opt out of purchasing a yogurt entirely. Implications for the food industry are discussed.