Biopolymer interactions during gastric digestion: Implications for nutrient delivery

Effects and mechanisms of ultrasound-assisted emulsification treatment on the curcumin delivery and digestive properties of myofibrillar protein-carboxymethyl cellulose complex emulsion gel

Different emulsion gel systems are widely applied to deliver functional ingredients. The effects and mechanisms of ultrasound-assisted emulsification (UAE) treatment and carboxymethyl cellulose (CMC) modifying the curcumin delivery properties and in vitro digestibility of the myofibrillar protein (MP)-soybean oil emulsion gels were investigated. The rheological properties, droplet size, protein and CMC distribution, ultrastructure, surface hydrophobicity, sulfhydryl groups, and zeta potential of emulsion gels were also measured. Results indicate that UAE treatment and CMC addition both improved curcumin encapsulation and protection efficiency in MP emulsion gel, especially for the UAE combined with CMC (UAE-CMC) treatment which encapsulation efficiency, protection efficiency, the release rate, and bioaccessibility of curcumin increased from 86.75 % to 97.67 %, 44.85 % to 68.85 %, 18.44 % to 41.78 %, and 28.68 % to 44.93 % respectively. The protein digestibility during the gastric stage was decreased after the CMC addition and UAE treatment, and the protein digestibility during the intestinal stage was reduced after the CMC addition. The fatty acid release rate was increased after CMC addition and UAE treatment. Apparent viscosity, storage modulus, and loss modulus were decreased after CMC addition while increased after UAE and UAE-CMC treatment especially the storage modulus increased from 0.26 Pa to 41 Pa after UAE-CMC treatment. The oil size was decreased, the protein and CMC concentration around the oil was increased, and a denser and uniform emulsion gel network structure was formed after UAE treatment. The surface hydrophobicity, free SH groups, and absolute zeta potential were increased after UAE treatment. The UAE-CMC treatment could strengthen the MP emulsion gel structure and decrease the oil size to increase the curcumin delivery properties, and hydrophobic and electrostatic interaction might be essential forces to maintain the emulsion gel.

Physiochemical changes, metabolite discrepancies of brown seaweed-derived sulphated polysaccharides in the upper gastrointestinal tract and their effects on bioactive expression

Brown seaweed-derived polysaccharides, notably fucoidan and laminarin, are known for their extensive array of bioactivities and physicochemical properties. However, the effects of upper digestive tract modification on the bioactive performance of fucoidan and laminarin fractions (FLFs) sourced from Australian native species are largely unknown. Here, the digestibility and bioaccessibility of FLFs were evaluated by tracking the dynamic changes in reducing sugar content (CR), profiling the free monosaccharide composition using LC-MS, and comparing high-performance gel permeation chromatography profile variation via LC-SEC-RI. The effects of digestive progression on bioactive performance were assessed by comparing the antioxidant and antidiabetic potential of FLFs and FLF digesta. We observed that molecular weight (Mw) decreased during gastric digestion indicating that FLF aggregates were disrupted in the stomach. During intestinal digestion, Mw gradually decreased and CR increased indicating cleavage of glycosidic bonds releasing free sugars. Although the antioxidant and antidiabetic capacities were not eliminated by the digestion progression, the bioactive performance of FLFs under a digestive environment was reduced contrasting with the same concentration level of the undigested FLFs. These data provide comprehensive information on the digestibility and bioaccessibility of FLFs, and shed light on the effects of digestive progression on bioactive expression.

Delivery of encapsulated bioactive compounds within food matrices to the digestive tract: recent trends and future perspectives

Encapsulation technologies have achieved encouraging results improving the stability, bioaccessibility and absorption of bioactive compounds post-consumption. There is a bulk of published research on the gastrointestinal behavior of encapsulated bioactive food materials alone using in vitro and in vivo digestion models, but an aspect often overlooked is the impact of the food structure, which is much more complex to unravel and still not well understood. This review focuses on discussing the recent findings in the application of encapsulated bioactive components in fabricated food matrices. Studies have suggested that the integration of encapsulated bioactive compounds has been proven to have an impact on the physicochemical characteristics of the finished product in addition to the protective effect of encapsulation on the fortified bioactive compound. These products containing bioactive compounds undergo further structural reorganization during digestion, impacting the release and emptying rates of fortified bioactive compounds. Thus, by manipulation of various food structures and matrices, the release and delivery of these bioactive compounds can be altered. This knowledge provides new opportunities for designing specialized foods for specific populations.

Natural Biomolecule Ovomucin-Chitosan Oligosaccharide Self-Assembly Nanogel for Lutein Application Enhancement: Characterization, Environmental Stability and Bioavailability

As an essential nutrient, lutein (LUT) has the ability to aid in the prevention of eye diseases, cardiovascular diseases, and cancer. However, the application of LUT is largely restricted by its poor solubility and susceptibility to oxidative degradation. Thus, in this study, LUT-loaded nanogel (OVM-COS-LUT) was prepared by a self-assembly of ovomucin (OVM) and chitosan oligosaccharide (COS) to enhance the effective protection and bioavailability of LUT. The nanogel had excellent dispersion (PDI = 0.25) and an 89.96% LUT encapsulation rate. XRD crystal structure analysis confirmed that the encapsulated LUT maintained an amorphous morphology. In addition, the nanogel showed satisfactory stability with pH levels ranging from 2 to 9 and high ionic strengths (>100 mM). Even under long-term storage, the nanogel maintained an optimistic stabilization and protection capacity; its effective retention rates could reach 96.54%. In vitro, digestion simulation showed that the bioaccessibility and sustained release of OVM-COS-LUT nanogel was superior to that of free LUT. The nanogel provided significant antioxidant activity, and no significant harmful effects were detected in cytotoxicity analyses at higher concentrations. In summary, OVM-COS-LUT can be utilized as a potential safe oral and functional carrier for encapsulating LUT.

Nisin lantibiotic prevents NAFLD liver steatosis and mitochondrial oxidative stress following periodontal disease by abrogating oral, gut and liver dysbiosis

Oral microbiome dysbiosis mediates chronic periodontal disease, gut microbial dysbiosis, and mucosal barrier disfunction that leads to steatohepatitis via the enterohepatic circulation. Improving this dysbiosis towards health may improve liver disease. Treatment with antibiotics and probiotics have been used to modulate the microbial, immunological, and clinical landscape of periodontal disease with some success. The aim of the present investigation was to evaluate the potential for nisin, an antimicrobial peptide produced by Lactococcus lactis, to counteract the periodontitis-associated gut dysbiosis and to modulate the glycolipid-metabolism and inflammation in the liver. Periodontal pathogens, namely Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia and Fusobacterium nucleatum, were administrated topically onto the oral cavity to establish polymicrobial periodontal disease in mice. In the context of disease, nisin treatment significantly shifted the microbiome towards a new composition, commensurate with health while preventing the harmful inflammation in the small intestine concomitant with decreased villi structural integrity, and heightened hepatic exposure to bacteria and lipid and malondialdehyde accumulation in the liver. Validation with RNA Seq analyses, confirmed the significant infection-related alteration of several genes involved in mitochondrial dysregulation, oxidative phosphorylation, and metal/iron binding and their restitution following nisin treatment. In support of these in vivo findings indicating that periodontopathogens induce gastrointestinal and liver distant organ lesions, human autopsy specimens demonstrated a correlation between tooth loss and severity of liver disease. Nisin's ability to shift the gut and liver microbiome towards a new state commensurate with health while mitigating enteritis, represents a novel approach to treating NAFLD-steatohepatitis-associated periodontal disease.

Particle size and water content impact breakdown and starch digestibility of chickpea snacks during in vitro gastrointestinal digestion

Chickpeas are an agriculturally-important legume that are an excellent source of protein, fiber, and minerals. Developing chickpea-based snacks could provide consumers with snack products rich in protein and other nutrients. In this study, chickpea puree (high moisture content) and cracker (low moisture content) were each produced with large (7 mm sieve; coarse) or small (2 mm sieve; fine) particle size to investigate the impact of initial particle size and moisture content on particle breakdown, starch hydrolysis, and protein hydrolysis during in vitro digestion. All treatments underwent static in vitro oral digestion, dynamic gastric digestion in the Human Gastric Simulator (HGS), and static in vitro small intestinal digestion. The emptying rate from the HGS was significantly (p < 0.05) higher for fine puree compared to the other treatments, due to higher saturation ratio and smaller initial particle size. The reducing sugars and free amino groups released (representing starch and protein hydrolysis, respectively) from fine puree were higher than coarse puree, and fine cracker was higher than coarse cracker due to the influence of initial particle size. For example, after 360 min total in vitro digestion, the starch hydrolysis of the fine cracker (48.1 ± 3.2%) was significantly higher than (p < 0.05) the coarse cracker (36.3 ± 5.8%). Overall, crackers had higher protein and starch hydrolysis compared to puree in the liquid phase during digestion. The study showed that both the smaller initial particle size and drying significantly (p < 0.05) increased the particle size reduction during gastric digestion and starch and protein digestibility in chickpea-based snacks.

The digestive behavior of pectin in human gastrointestinal tract: a review on fermentation characteristics and degradation mechanism

Pectin is widely spread in nature and it develops an extremely complex structure in terms of monosaccharide composition, glycosidic linkage types, and non-glycosidic substituents. As a non-digestible polysaccharide, pectin exhibits resistance to human digestive enzymes, however, it is easily utilized by gut microbiota in the large intestine. Currently, pectin has been exploited as a novel functional component with numerous physiological benefits, and it shows a promising prospect in promoting human health. In this review, we introduce the regulatory effects of pectin on intestinal inflammation and metabolic syndromes. Subsequently, the digestive behavior of pectin in the upper gastrointestinal tract is summarized, and then it will be focused on pectin's fermentation characteristics in the large intestine. The fermentation selectivity of pectin by gut bacteria and the effects of pectin structure on intestinal microecology were discussed to highlight the interaction between pectin and bacterial community. Meanwhile, we also offer information on how gut bacteria orchestrate enzymes to degrade pectin. All of these findings provide insights into pectin digestion and advance the application of pectin in human health.

Effects of carboxymethyl cellulose on the emulsifying, gel and digestive properties of myofibrillar protein-soybean oil emulsion

Improving the qualities of vegetable oil replaced animal fat meat products is particularly fascinating for the development of healthy meat products. This work was designed to investigate the effects of different carboxymethyl cellulose (CMC) concentrations (0.01 %, 0.05 %, 0.1 %, 0.2 %, and 0.5 %) on the emulsifying, gelation, and digestive properties of myofibrillar protein (MP)-soybean oil emulsions. The changes in MP emulsion characteristics, gelation properties, protein digestibility, and oil release rate were determined. Results demonstrated that CMC addition decreased the average droplet size and increased the apparent viscosity, storage modulus, and loss modulus of MP emulsions, and a 0.5 % CMC addition significantly increased the storage stability during 6 weeks. Lower CMC addition (0.01 % to 0.1 %) increased the hardness, chewiness, and gumminess of emulsion gel especially for the 0.1 % CMC addition, while higher CMC (0.5 %) content decreased the texture properties and water holding capacity of emulsion gels. The addition of CMC decreased protein digestibility during the gastric stage, and 0.01 % and 0.05 % CMC addition significantly decreased the free fatty acid release rate. In summary, the addition of CMC could improve the stability of MP emulsion and the texture properties of the emulsion gels, and decrease protein digestibility during the gastric stage.

Factors associated with treatment failure, and possible applications of probiotic bacteria in the arsenal against Helicobacter pylori

INTRODUCTION

Helicobacter pylori is a widespread helical Gram-negative bacterium, which causes a variety of stomach disorders, such as peptic ulcer, chronic atrophic gastritis, and gastric cancer. This microbe frequently colonizes the mucosal layer of the human stomach and survives in the inhospitable microenvironment, by adapting to this hostile milieu.

AREAS COVERED

In this extensive review, we describe conventional antibiotic treatment regimens used against H. pylori including, empirical, tailored, and salvage therapies. Then, we present state-of-the-art information about reasons for treatment failure against H. pylori. Afterward, the latest advances in the use of probiotic bacteria against H. pylori infection are discussed. Finally, we propose a polymeric bio-platform to provide efficient delivery of probiotics for H. pylori infection.

EXPERT OPINION

For effective probiotic delivery systems, it is necessary to avoid the early release of probiotics at the acidic stomach pH, to protect them against enzymes and antimicrobials, and precisely target H. pylori bacteria which have colonized the antrum area of the stomach (basic pH).

In vitro digestion models for the design of safe and nutritious foods

Responsible development of future foods requires in depth understanding of food digestion in the human body based on robust research models, ranging from in vitro models to randomized controlled human trials. This chapter overviews fundamental aspects of food digestion, namely bioaccessibility and bioavailability, and models mirroring gastric, intestinal, and colonic conditions. Second, the chapter demonstrates the potential of in vitro digestion models to help screen adverse effects of food additives, such as Titanium dioxide or carrageenan, or underpin the determinants of macro- and micronutrient digestion in different strata of the population, for example digestion of emulsions. Such efforts support rationalized design of functional foods, such as infant formulae, cheese, cereals and biscuits which are validated in vivo or in randomized controlled trials.

Chain conformation, mucoadhesive properties of fucoidan in the gastrointestinal tract and its effects on the gut microbiota

Fucoidans are valuable marine polysaccharides with various bioactivities and physicochemical properties. However, its digestive properties, mucoadhesive properties, and bioactivity in the gastrointestinal tract are still unclear. In this study, simulated digestion, fecal fermentation in vitro, and rheology models were utilized to investigate the chain conformation, influence on gut microbiota, and mucin adhesive properties of fucoidan from the sea cucumber Thelenota ananas (Ta-FUC). The results showed that Ta-FUC was nondigestible with a temporary decrease in molecular weight in gastric conditions, accompanied by the chain conformation becoming more flexible. Moreover, Ta-FUC exhibited strong mucin adhesive function in the simulated intestinal environment, with supramolecular disulfide, hydrogen, and hydrophobic interactions in order of intensity. During fermentation, Ta-FUC was degraded by the intestinal flora to produce various short-chain fatty acids and promoted the relative abundance of Bacteroidota and Firmicutes, reducing the proportion of Proteobacteria. Therefore, these results indicate that Ta-FUC could be a potential prebiotic and ingredient for developing targeted delivery systems in the functional food and pharmaceutical industries.

Therapeutic potential of non-starch polysaccharides on type 2 diabetes: from hypoglycemic mechanism to clinical trials

Non-starch polysaccharides (NSPs) have been reported to exert therapeutic potential on managing type 2 diabetes mellitus (T2DM). Various mechanisms have been proposed; however, several studies have not considered the correlations between the anti-T2DM activity of NSPs and their molecular structure. Moreover, the current understanding of the role of NSPs in T2DM treatment is mainly based on in vitro and in vivo data, and more human clinical trials are required to verify the actual efficacy in treating T2DM. The related anti-T2DM mechanisms of NSPs, including regulating insulin action, promoting glucose metabolism and regulating postprandial blood glucose level, anti-inflammatory and regulating gut microbiota (GM), are reviewed. The structure-function relationships are summarized, and the relationships between NSPs structure and anti-T2DM activity from clinical trials are highlighted. The development of anti-T2DM medication or dietary supplements of NSPs could be promoted with an in-depth understanding of the multiple regulatory effects in the treatment/intervention of T2DM.

Particle-dependent reproduction and exogenic biopolymer secretion of protozoa co-cultured rotifers

The rotifer-specific exogenic biopolymer, named Rotimer and its related molecular processes are affected by physical and chemical factors (e.g., temperature, pH or metal ions); however, the study of biological influences (e.g., the presence protozoa) concerning the particle-dependent reproduction (egg laying) and 'biopolymer producing capacity' (BPC) of rotifers is the objective of the present work. Non-planktonic rotifer species (Philodina acuticornis, Adineta vaga, Euchlanis dilatata, and Lecane bulla) were studied in paired micrometazoa-protozoa co-cultures involving Paramecium, Diplonema, and Amoeba. These protozoa can be beneficial food sources, enhancing reproduction, or even toxic factors for the above-mentioned animals, but can also function as particle-like mechanical stimulators. Furthermore, current studies reveal that bdelloids, similarly to monogonants, produce filamentous exudate; moreover, the body of bdelloids is covered by their exudate, unlike that of monogonants, especially in the case of A. vaga. A mathematical formula was developed as an improved version of a previously published viability marker to characterize the BPC and the relative amount of produced exudate in different conditions. Rotifer species secreting biopolymers appear to be a general trait indicating a common evolutionary background (e.g., calcium- and particle dependency) of such molecules; therefore, the BPC becomes an experiential sublethal influencing marker to these micrometazoans.

Structural breakdown of starch-based foods during gastric digestion and its link to glycemic response: In vivo and in vitro considerations

The digestion of starch-based foods in the small intestine as well as factors affecting their digestibility have been previously investigated and reviewed in detail. Starch digestibility has been studied both in vivo and in vitro, with increasing interest in the use of in vitro models. Although previous in vivo studies have indicated the effect of mastication and gastric digestion on the digestibility of solid starch-based foods, the physical breakdown of starch-based foods prior to small intestinal digestion is often less considered. Moreover, gastric digestion has received little attention in the attempt to understand the digestion of solid starch-based foods in the digestive tract. In this review, the physical breakdown of starch-based foods in the mouth and stomach, the quantification of these breakdown processes, and their links to physiological outcomes, such as gastric emptying and glycemic response, are discussed. In addition, the physical breakdown aspects related to gastric digestion that need to be considered when developing in vitro-in vivo correlation in starch digestion studies are discussed. The discussion demonstrates that physical breakdown prior to small intestinal digestion, especially during gastric digestion, should not be neglected in understanding the digestion of solid starch-based foods.