The impact of food-grade carrageenans and consumer age on the in vitro proteolysis of whey proteins

Modulation of gut-microbiota through probiotics and dietary interventions to improve host health

Dietary patterns play an important role in regards to the modulation and control of the gut microbiome composition and function. The interaction between diet and microbiota plays an important role in order to maintain intestinal homeostasis, which ultimately affect the host's health. Diet directly impacts the microbes that inhabit the gastrointestinal tract (GIT), which then contributes to the production of secondary metabolites, such as short-chain fatty acids, neurotransmitters, and antimicrobial peptides. Dietary consumption with genetically modified probiotics can be the best vaccine delivery vector and protect cells from various illnesses. A holistic approach to disease prevention, treatment, and management takes these intrinsically linked diet-microbes, microbe-microbe interactions, and microbe-host interactions into account. Dietary components, such as fiber can modulate beneficial gut microbiota, and they have resulting ameliorative effects against metabolic disorders. Medical interventions, such as antibiotic drugs can conversely have detrimental effects on gut microbiota by disputing the balance between Bacteroides and firmicute, which contribute to continuing disease states. We summarize the known effects of various dietary components, such as fibers, carbohydrates, fatty acids, vitamins, minerals, proteins, phenolic acids, and antibiotics on the composition of the gut microbiota in this article in addition to the beneficial effect of genetically modified probiotics and consequentially their role in regards to shaping human health. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Carrageenan as a Potential Factor of Inflammatory Bowel Diseases

Carrageenan is a widely used food additive and is seen as a potential candidate in the pharmaceutical industry. However, there are two faces to carrageenan that allows it to be used positively for therapeutic purposes. Carrageenan can be used to create edible films and for encapsulating drugs, and there is also interest in the use of carrageenan for food printing. Carrageenan is a naturally occurring polysaccharide gum. Depending on the type of carrageenan, it is used in regulating the composition of intestinal microflora, including the increase in the population of Bifidobacterium bacteria. On the other hand, the studies have demonstrated the harmfulness of carrageenan in animal and human models, indicating a direct link between diet and intestinal inflammatory states. Carrageenan changes the intestinal microflora, especially Akkermansia muciniphilia, degrades the mucous barrier and breaks down the mucous barrier, causing an inflammatory reaction. It directly affects epithelial cells by activating the pro-inflammatory nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) pathway. The mechanism is based on activation of the TLR4 receptor, alterations in macrophage activity, production of proinflammatory cytokines and activation of innate immune pathways. Carrageenan increases the content of Bacteroidetes bacteria, also causing a reduction in the number of short chain fatty acid (SCFA)-producing bacteria. The result is damage to the integrity of the intestinal membrane and reduction of the mucin layer. The group most exposed to the harmful effects of carrageenan are people suffering from intestinal inflammation, including Crohn disease (CD) and ulcerative colitis (UC).

Carrageenan impact on digestive proteolysis of meat proteins in meatballs or soluble hydrolyzed collagen

In a health-conscious age, vivid discussion has been made on the healthfulness of processed foods and food additives. This study focuses on carrageenan (CGN), an approved but debated family of sulphated galactans from algae used as gelling, thickening and stabilizing agents but with indications of possible adverse effects, including as an inhibitor of digestive proteolysis. To challenge this inhibitory hypothesis, food-grade kappa-, iota and lambda-CGN preparations were used to produce beef meatballs whose proteolysis was studied using an in vitro digestion model coupled to various proteomic analyses. Results show that CGN anti-nutritional effects are abolished in beef meatballs. Specifically, proteomic analysis of gastric digesta of myosin light chain 1 (MYL1), alpha skeletal muscle (ACTA1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and fructose-bisphosphate aldolase (ALDOA) reveal no appreciable differences in the profiles of bioaccessible peptides. Separate digestions of a soluble collagen hydrolysate show CGN does inhibit proteolysis of soluble collagen, therefore supporting the notion that the meat matrix confers a shielding effect that eliminates CGN ability to interfere with digestive proteolysis. Thus, this work shows that CGN ability to hinder digestive proteolysis may not apply to all foods and contributes evidence important to the discussions on CGN uses, indications and regulatory status.

Encapsulation and stabilization of lactoferrin in polyelectrolyte ternary complexes

Effective delivery of the bioactive protein, lactoferrin (LF), remains a challenge as it is sensitive to environmental changes and easily denatured during heating, restricting its application in functional food products. To overcome these challenges, we formulated novel polyelectrolyte ternary complexes of LF with gelatin (G) and negatively charged polysaccharides, to improve the thermal stability of LF with retained antibacterial activity. Linear, highly charged polysaccharides were able to form interpolymeric complexes with LF and G, while coacervates were formed with branched polysaccharides. A unique multiphase coacervate was observed in the gum Arabic GA-LF-G complex, where a special coacervate-in-coacervate structure was found. The ternary complexes made with GA, soy soluble polysaccharide (SSP), or high methoxyl pectin (HMP) preserved the protein structures and demonstrated enhanced thermal stability of LF. The GA-LF-G complex was especially stable with >90% retention of the native LF after treatment at 90 °C for 2 min in a water bath or at 145 °C for 30 s, while the LF control had only ~ 7% undenatured LF under both conditions. In comparison to untreated LF, LF in ternary complex retained significant antibacterial activity on both Gram-positive and Gram-negative bacteria, even after heat treatment. These ternary complexes of LF maintain the desired functionality of LF, thermal stability and antibacterial activity, in the final products. The ternary complex structure, particularly the multiphase coacervate, may serve as a template for the encapsulation and stabilization of other bioactives and peptides.

Impact of Flaxseed Gums on the Colloidal Changes and In Vitro Digestibility of Milk Proteins

Flaxseed (Linum usitatissimum L.) mucilage is one of the most studied plant seed gums in terms of its techno-functional and health-promoting properties. Nonetheless, the interplay of flaxseed gum (FG) with other food biopolymers, such as milk proteins, under in vitro digestion conditions remains underexplored. The aim of the present work was to investigate the colloidal interplay between flaxseed gum (golden or brown) and milk proteins (sodium caseinate or whey protein isolate) under simulated in vitro digestion conditions and its relationship with the attained in vitro protein digestibility. The presence of flaxseed gum in the milk protein food models and in the oral food boluses obtained was associated with the occurrence of segregative microphase separation. Flaxseed gum exhibited a prominent role in controlling the acid-mediated protein aggregation phenomena, particularly in the sodium caseinate gastric chymes. The addition of FG in the food models was associated with a higher amount of intact total caseins and β-lactoglobulin at the end of the gastric processing step. Monitoring of the intestinal processing step revealed a very advanced cleavage of the whey proteins (>98%) and caseins (>90%). The degree of the milk protein hydrolysis achieved at the end of the intestinal processing was significantly higher in the systems containing flaxseed gum (i.e., 59−62%) than their gum-free protein counterparts (i.e., 46−47%). It was postulated that the electrostatic milk protein complexation capacity and, to a lesser extent, the thickening effect of flaxseed gum influenced the in vitro digestibility of the milk proteins.

Effects of κ-carrageenan of gel quality on threadfin bream (Nemipterus spp.) surimi containing salted duck egg white powder

This study aimed to evaluate the combined effect of κ-carrageenan and salted duck egg white powder (SDEWP) in improving the gel quality of threadfin bream surimi. Effects of κ-carrageenan at different levels (0-2 %) on gel properties of threadfin bream surimi without and with salted duck egg white powder at 3 % (protein equivalent) were investigated. A combination of 0.5 % κ-carrageenan and SDEWP increased breaking force of surimi gel by 139.7 % and deformation by 55.1 %, compared to the control (P < 0.05). The expressible moisture content (EMC) was decreased by 50.0 % in the surimi gel added with 0.5 % κ-carrageenan and SDEWP. Hardness, cohesiveness, gumminess, and chewiness of surimi gel were also improved (P < 0.05). However, springiness of surimi gel was not affected. SDEWP reduced proteolytic degradation in surimi gel. Surimi gel with augmented whiteness was attained when κ-carrageenan was added at higher levels. Microstructure of surimi gel shown that the gel became denser and more uniform when added with 0.5 % κ-carrageenan and SDEWP. Therefore, κ-carrageenan can be used to enhance the effectiveness of SDEWP and further improve the gel quality of threadfin bream surimi added with SDEWP.

Impact of alfalfa (Medicago sativa L.) galactomannan on the microstructural and physicochemical changes of milk proteins under static in-vitro digestion conditions

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The impact of alfalfa galactomannan (AAG) on the digestibility of milk proteins was studied.

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AAG mediated the intragastric aggregation of both sodium caseinate and whey protein isolate.

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AAG affected only the peptic cleavage of caseins and β-lactoglobulin in the gastric chymes.

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AAG enhanced the free amino acids release in the gastric chymes regardless of the protein type.

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The free amino acids release rate in the intestinal chymes were adversely related to AAG content.

This paper reports on the impact of alfalfa galactomannan (AAG, 0.1, 0.5 or 1% wt.) on the colloidal changes and digestibility of sodium caseinate (NaCN) and whey protein isolate (WPI) dispersions (10% wt.) under static in-vitro digestion conditions. Static laser light scattering and confocal laser scanning microscopy-assisted assessment of the NaCN-based gastric chymes confirmed the ability of AAG to control the acid-induced protein coagulation phenomena. Contrarily, the presence of AAG in the WPI-based gastric chymes was associated with the formation of larger aggregates due to the occurrence of segregative microphase separation. The kinetic modelling of the SDS-PAGE densitometric data showed that the intragastric peptic cleavage rates were higher for caseins than whey proteins (β-lactoglobulin, α-lactalbumin). However, free amino acid (FAA) release rates did not exceed 12% under intragastric conditions, whilst notably higher release rates were achieved in the intestinal digesta (36–52%). In all cases, the FAA release rates significantly increased in the presence of AAG.

Application of ultrasound treatment for improving the quality of infant meat puree

Infant meat puree has an indispensable effect on the oral development and nutritional intake of infants. However, commercially available products have poor texture and relatively low digestibility. In this study, ultrasound (20 kHz and 200 W, 400 W, or 600 W) was applied to the pretreatment of raw meat for preparing infant meat puree for 15 min, 30 min, and 45 min. To assess the impact of ultrasound on infant meat puree, the viscosity, texture, water distribution, particle size and in vitro digestibility were determined. The results showed that, compared with control, viscosity and hardness of meat puree decreased and the texture was better in 400 W and 600 W groups. The content of immobilized water increased in comparison with the control. Ultrasound had no obvious effect on the digestibility of meat puree in gastric phase, but it increased the digestibility in intestinal phase with the highest digestibility (80.85%±3.33) in 600 W, 15 min group. Overall, the ultrasound parameters of 600 W for 15 min can be selected as the best condition to process infant meat puree. The findings provide a new perspective for the improvement of infant meat puree.

Algae-derived hydrocolloids in foods: applications and health-related issues

Hydrocolloids are a class of food additives with broad applications in the food industry to develop structure in food ingredients. Hydrocolloids can be synthetic, plant-based, or animal-based. Increasing consumer awareness has led to the use of natural food ingredients derived from natural sources, making algae-derived hydrocolloids more appealing nowadays. Algae-derived hydrocolloids such as carrageenan, agar, and alginate are widely used in the food industry as thickening, gelling, and emulsifying agents. Carrageenans are sulfated polysaccharides with diverse structural specificities. The safety of carrageenan use in the food industry has been widely debated recently due to the reported pro-inflammatory activities of carrageenan and the probable digestion of carrageenan by the gut microbiota to generate pro-inflammatory oligosaccharides. In contrast, both agar and alginate are primarily nontoxic, and generally no dispute regarding the use of the same in food ingredients. This review provides an overview of the algae industry, the food additives, the algae-derived hydrocolloids, the applications of algae-derived hydrocolloids in food industries, health-related studies, and other sectors, along with future perspectives. Even though differences of opinion exist in the use of carrageenan, it is continued to be used by the food industry and will be used until suitable alternatives are available. In summary, algal hydrocolloids are 'label-friendly' and considered a safe option against synthetic additives.

Entrapment of natural compounds in spray-dried and heat-dried iota-carrageenan matrices as functional ingredients in surimi gels

Two drying methods (spray drying and heat drying) were used to entrap various natural compounds within a matrix of iota-carrageenan. The natural compounds were, namely, collagen hydrolysate (CH), pomegranate polyphenolic extract (PP) and shrimp lipid extract (SL). The resulting dry powders were compared in terms of water solubility, entrapment efficiency, hydrodynamic particle properties, ζ potential and antioxidant properties (ABTS radical scavenging capacity, ferric ion reducing power and Folin-reactive substances). Dry powders and plain compounds were incorporated into squid surimi gels, and after in vitro simulated gastrointestinal digestion (sGID), the residual antioxidant and angiotensin-converting enzyme (ACE)-inhibitory activities were evaluated. All powders showed antioxidant properties, electronegative ζ potential and great entrapment efficiency after rehydration (ranging from ∼70 to 97%). The heat-dried powders were composed of microparticles ranging from 177 to 380 μm resulting in low water solubility (21.6-36.1%), while the average particle size and solubility values of spray-dried preparations were 2.9-13.2 μm and >86%, respectively. In contrast to the plain compounds, the addition of any of the microparticle dried preparations allowed obtaining well-conformed surimi gels. The ACE-inhibitory capacity of the surimi gels after sGID was increased by the addition of any of the compounds studied, but to a lesser extent by their entrapment forms (except with the entrapped SL). The antioxidant activities of gels with the entrapped compounds were even lower than those of gels without bioactives in some cases. In conclusion, the addition of dried microparticles did not increase the biological activity as compared to the plain compounds; however, they were beneficial to ensure adequate gel consistency.

Food-grade carrageenans and their implications in health and disease

Food additives, often used to guarantee the texture, shelf-life, taste, and appearance of processed foods, have gained widespread attention due to their increased link to the growing incidence of chronic diseases. As one of the most common additives, carrageenans have been used in human diets for hundreds of years. While classified as generally recognized as safe (GRAS) for human consumption, numerous studies since the 1980s have suggested that carrageenans, particularly those with random coil conformations, may have adverse effects on gastrointestinal health, including aggravating intestinal inflammation. While these studies have provided some evidence of adverse effects, the topic is still controversial. Some have suggested that the negative consequence of the consumption of carrageenans may be structure dependent. Furthermore, pre-existing conditions may predispose individuals to varied outcomes of carrageenan intake. In this review, structure-function relationships of various carrageenans in the context of food safety are discussed. We reviewed the molecular mechanisms by which carrageenans exert their biological effects. We summarized the findings associated with carrageenan intake in animal models and clinical trials. Moreover, we examined the interactions between carrageenans and the gut microbiome in the pathogenesis of gastrointestinal disorders. This review argues for personalized guidance on carrageenan intake based on individuals' health status. Future research efforts that aim to close the knowledge gap on the effect of low-dose and chronic carrageenan intake as well as interactions among food additives should be conducive to the improved safety profile of carrageenans in processed food products.

Food and Beverages Containing Algae and Derived Ingredients Launched in the Market from 2015 to 2019: A Front-of-Pack Labeling Perspective with a Special Focus on Spain

Algae are a source of functional ingredients, with a large spectrum of healthy and functional compounds. Therefore, this study aimed to provide an overview on commercialized food and beverages made from algae and derived ingredients, with emphasis on the Spanish market, relying on the front-of-pack labeling. For this reason, the Mintel Global New Products Database was searched for foods and beverages containing “algae” ingredients, launched during the period 2015–2019. A total of 13,090 items were found worldwide, including 5720 items in Europe, in which 436 items were in Spain. Regardless of the market (global, European, and Spanish), a similar number of products categories (n = 20), dominant categories (dairy and desserts and ice cream) and dominant algal ingredient (carrageenans) were found. Nutritional information retrieved from Spanish products underlined that algae-based snacks had significantly lower energy, fat, and salt content compared to algae-free counterparts. On the contrary, spirulina- enriched ready to drink beverages had significantly higher energy and salt than algae-free. As such, reading the nutritional labeling is crucial to selecting products that suit consumer needs or/and expectations. Furthermore, only 8% of products reported the algal species and the level of inclusion, so this study emphasizes the importance of labeling legislation to provide complete product information to consumers.

Addition of Anionic Polysaccharide Stabilizers Modulates In Vitro Digestive Proteolysis of a Chocolate Milk Drink in Adults and Children

There is a need to better understand the possible anti-nutritional effect of food stabilizers on the digestibility of important macronutrients, like proteins. This study hypothesized that the anionic nature of κ-, ι-, λ-, Carrageenan (CGN) and xanthan gum directs their interactions with food proteins leading to their subsequent attenuated digestive proteolysis. Model chocolate milk drinks were tested for their colloidal properties, viscosity and proteolytic breakdown in adults and children using in vitro digestion models coupled with proteomic analyses. SDS-PAGE analyses of gastro-intestinal effluents highlight stabilizers hinder protein breakdown in adults and children. Zeta potential and colloidal particle size were the strongest determinants of stabilizers’ ability to hinder proteolysis. LC-MS proteomic analyses revealed stabilizer addition significantly reduced bioaccessibility of milk-derived bioactive peptides with differences in liberated peptide sequences arising mainly from their location on the outer rim of the protein structures. Further, liberation of bioactive peptides emptying from a child stomach into the intestine were most affected by the presence of ι-CGN. Overall, this study raises the notion that stabilizer charge and other properties of edible proteins are detrimental to the ability of humans to utilize the nutritional potential of such formulations. This could help food professionals and regulatory agencies carefully consider the use of anionic stabilizers in products aiming to serve as protein sources for children and other liable populations.