Simulated Intestinal Digestion Research Articles

The production of stirred yogurt fortified with prebiotic xylooligosaccharide, probiotic and synbiotic microcapsules

Xylooligosaccharides are considered safe emergent food ingredients with various promising biological activities. Herein, xylooligosaccharides were produced through enzymatic hydrolysis of beech wood xylan and their prebiotic activity was evaluated. The reported results indicated that the produced xylooligosaccharides own confident influence for stimulating the growth of different useful bacterial strains with a significant resistance to simulated intestinal juice digestion but decomposed by more than 50% in simulated gastric juice. Therefore, encapsulation of the produced xylooligosaccharides was assessed to enhance its gastric-digestion resistance. The results indicated that the encapsulation matrix composed of sodium alginate and whey protein concentrate led to an entrapment efficiency of 85.26% for xylooligosaccharides with 100% protective efficiency in simulated gastric juice. Moreover, the incorporation of the produced xylooligosaccharides in the preparation of synbiotic microcapsules including the probiotic Lactobacillus acidophilus was evaluated. The results indicated that the entrapment efficiency for XOS in the prepared synbiotic microcapsule was 93.89%. Finally, the applicability of the produced xylooligosaccharides in the manufacture of stirred yogurt fortified with the probiotic Lactobacillus acidophilus was evaluated. Fortification with the produced xylooligosaccharides maintained the viability of the probiotic strain along the storage period with significant viability propagation (10.45 log cfu/mL after 20 days storage period) by the use of synbiotic microcapsules.

Effects of microbial transglutaminase on the gelling property and in vitro digestibility of fish scale gelatin from grass carp

Fish scales are good sources of gelatin, but the wide application of fish scale gelatin (FSG) is highly restricted due to its poor gelling property. In this study, microbial transglutaminase (MTG) was utilized to improve the gelling property of FSG from grass carp. The effects of MTG on the gel strength, textural property, rheological property, triple-helix structure, chemical structure, thermal property, and microstructure of FSG were investigated. Then, the in vitro gastric and simulated intestinal digestibility of the cross-linked FSG were further studied. The cross-linking of FSG by MTG at all concentrations increased the gel strength, hardness, chewiness, peak temperature, and sol-gel transition temperatures. The MTG at a low concentration promoted the formation of an ordered triple-helix structure and a compact network in FSG, while the high-concentration MTG had an opposite effect. Besides, the cross-linking of FSG by MTG generally increased the digestion time of FSG and allowed the release of more unique peptides during gastric and intestinal digestion. Peptides with various bioactivities were released after the simulated intestinal digestion of the native and modified FSGs. This study may provide some guidance for the deep utilization of FSG in the food industry and further promote the exploitation of fish scales.

Co-incorporation of probiotics into 3D printed custard cream with hydrophilic and hydrophobic bioactives

There is an emerging need for food with specific functionality and nutrition. This work investigated the feasibility of developing 3D printed custard cream co-enriched with probiotics, hydrophilic and hydrophobic bioactives. The effect of EGCG and resveratrol on survival of probiotics encapsulated in 3D printed custard cream during storage, heating, and simulated gastrointestinal conditions were investigated. The addition of bioactives and probiotic coacervates didn't exhibit great influence on the emulsion structure, gel-like rheological behavior and great printing properties of the resulting custard cream samples. The cell survival of encapsulated probiotics in the custard cream with bioactives was prominently increased during storage at 4 °C as well as under heating at 63 and 75 °C. The co-encapsulation of probiotics, EGCG and resveratrol in the custard cream improved the viability of probiotic in the gastrointestinal tract. There was only a 0.85 log and 1.52 log loss of probiotic viability in the custard cream after digestion in simulated gastric and small intestinal digestion conditions. Meanwhile, EGCG and resveratrol in this sample showed a maximum release after simulated digestion, which reached 68.10% and 71.69% release at the end of digestion. Therefore, the co-encapsulation of EGCG, resveratrol with probiotic in this 3D printable custard cream delivery system would be an efficient approach to simultaneous delivery bioactives and probiotic in the gastrointestinal tract with synergistic beneficial effects.

In Vitro Hypoglycemic Potential, Antioxidant and Prebiotic Activity after Simulated Digestion of Combined Blueberry Pomace and Chia Seed Extracts

This study aimed to evaluate the hypoglycemic potential, antioxidant activity and prebiotic activity of a hydroalcoholic extract of blueberry pomace (BP), an aqueous extract of chia seeds (CS) and a novel combination of BP–CS extracts (BCM) for further use as ingredient of functional food. Spectrometric and HPLC analyses were used to characterize the total phenolic and flavonoid content and composition of BP, while CS was analyzed for total carbohydrate content. Data showed that the BCM mixture exerted an inhibition of α-amylase activity, which was 1.36 times higher than that of BP and 1.25 higher than CS extract. The mixture also showed better scavenging activity of free DPPH radicals than individual extracts, and had an IC50 value of 603.12 µg/mL. In vitro testing indicated that both serum- and colon-reaching products of simulated intestinal digestion of BCM presented the capacity to protect Caco-2 intestinal cells against oxidative stress by inhibition of reactive oxygen species production. In addition, the colon-reaching product of BCM digestion had the capacity to significantly (p < 0.05) stimulate the growth of Lactobacillus rhamnosus and Lactobacillus acidophilus, revealing a prebiotic potential. All these results indicated that improved biological activity of the novel combination of BP and CS extracts could be due to the synergistic action of constituents. The combination is recommended for further testing and the development of novel functional food for controlling type 2 diabetes and gastrointestinal conditions.

Evaluating the efficacy of non-thermal microbial load reduction treatments of heat labile food components for in vitro fermentation experiments.

Increasingly, in vitro simulated colon fermentations are being used as a pre-clinical step to assess the impacts of foods and drugs on the gut microbiota in a cost-effective manner. One challenge in such systems is that they are potentially susceptible to the influences of contaminating microbes in test materials. Simulated gastric and intestinal digestion can relieve some of these concerns, however, live microbes may remain that can confound analysis. Autoclave treatment of test materials is the surest way to eliminate these microbes but presents problems when using heat labile components such as resistant starch. In this study, liquid chemical sterilant alternatives to moist heat sterilization were explored for treating pulse flours for use during in vitro simulated colon fermentation. Key attributes considered in chemical selection were accessibility, impact on treated food components, and effectiveness of the treatments for reducing microbial load. Three chemicals were selected for evaluation, bleach, alcohol, and hydrogen peroxide, at varying concentrations. Flours chosen for testing were from green lentil, field pea, chickpea, or sprouted green lentil. All treatments significantly reduced microbial loads, though there were still detectable levels of microbes after alcohol treatments. Furthermore, in vitro simulated colon fermentations of the treated pulses showed minimal difference from the untreated control both in terms of microbial composition and short chain fatty acid production. Scanning electron microscopy showed minimal impact of sterilization treatments on the gross structure of the pulse flours. Together these results suggest that bleach and hydrogen peroxide treatments can be effective nonthermal treatments to eliminate contaminating microbes in pulse flours without causing significant damage to starch and other fermentable substrates. This is thus also a promising treatment method for other starchy food substrates, though further testing is required.

Changes of Bioactive Components and Antioxidant Capacity of Pear Ferment in Simulated Gastrointestinal Digestion In Vitro.

Fruit ferment is rich in polyphenols, organic acids, enzymes, and other bioactive components, which contribute to their antioxidant ability. In this study, we investigated the effect of the simulated gastric and intestinal digestion in vitro on the total phenolic content (TPC), total flavonoid content (TFC), phenolic components content, organic acid content, protease activity, superoxide dismutase (SOD) activity, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity (DPPH-RSA), hydroxyl (·OH) radical scavenging activity (·OH-RSA), and total reducing capacity in 'Xuehua' pear (Pyrus bretschneideri Rehd) ferment. The result showed that the TPC, TFC, protease activity, and phenolic components such as arbutin, protocatechuic acid, malic acid, and acetic acid showed a rising trend during the simulated gastric digestion in 'Xuehua' pear ferment, and these components might contribute to the increasing of ·OH-RSA and total reducing capacity. The SOD activity and epicatechin content showed an increasing trend at first and then a decreasing trend, which was likely associated with DPPH-RSA. During in vitro-simulated intestinal digestion, the majority of evaluated items reduced, except for protease activity, quercetin, and tartaric acid. The reason for the decreasing of bio-accessibility resulted from the inhibition of the digestive environment, and the transformation between substances, such as the conversion of hyperoside to quercetin. The correlation analysis indicated that the antioxidant capacity of 'Xuehua' pear ferment was mainly affected by its bioactive compounds and enzymes activity as well as the food matrices and digestive environment. The comparison between the digestive group with and without enzymes suggested that the simulated gastrointestinal digestion could boost the release and delay the degradation of phenolic components, flavonoids, and organic acid, protect protease and SOD activity, and stabilize DPPH-RSA, ·OH-RSA, and total reducing capacity in 'Xuehua' pear ferment; thus, the 'Xuehua' pear ferment could be considered as an easily digestible food.

Microencapsulation of Probiotics with Soy Protein Isolate and Alginate for the Poultry Industry.

Many probiotic products, with properly selected microorganisms, may not be effective for the intended purpose due to the low tolerance of microorganisms to gastrointestinal digestion. The microencapsulation seems to be one of the most promising techniques to protect probiotics against adverse environmental conditions. Therefore, the aim of this work was the design of soy protein isolate-alginate microcapsules for the encapsulation of probiotics for the poultry industry by the water-in-oil emulsion technique. To this end, the strain Ligilactobacillus salivarius CRL2217, with the ability to bind wheat germ agglutinin (WGA) on its surface and protect intestinal epithelial cells from the cytotoxicity of the glycoprotein, was used as model microorganism. Several parameters were varied in order to find the better conditions for microencapsulation: oil source and nature, SPI and sodium alginate concentration, stirring equipment and time for emulsion formation, CaCl2 concentration, and absence or presence of stirring after the addition of the CaCl2 solution. The survival of entrapped cells to a simulated gastric digestion and their survival and release during simulated intestinal digestion were also investigated. The obtained particles effectively protected L. salivarius CRL2217 from the proteolytic activity and low pH present in the gastric environment. Besides, their content was released in contact with a simulated intestinal juice, as viable counts and binding of WGA after a simulated intestinal digestion revealed. This work paves the way for the design of probiotic supplements for poultry including gastrointestinal digestion-susceptible bacteria.

The impact of different fermenting microbes on residual purine content in fermented lamb jerky following in vitro digestion

This is the first study to investigate the effect of different lactic acid bacteria fermentation methods on the purine content of mutton jerky and to examine the changes in purine in these fermented mutton jerky samples underan in vitro simulated digestive system to determine an efficient method for regulating exogenous purine intake. According to the analysis, x3-2b Lactobacillus plantarum and composite bacteria can directly reduce the purine content in fermented dried mutton and achieve the purpose of reducing the intake of purine. However, after simulated intestinal digestion, it was observed that the purine content of these different sample groups was significantly decreased, and 37x-3 Pediococcus pentosaceus had the better effect. It has been shown that the 37x-3 Pediococcus pentosaceus, Lactobacillus sake, and composite bacteria significantly enhance the degree to which residual purine is depleted in the large intestine during digestion. In sum, one potentially successful method of regulating exogenous purine consumption is the development of fermented meat products using certain beneficial bacteria as a starter.

Porcine bile acids promote the utilization of fat and vitamin A under low-fat diets.

Fat-soluble vitamin malabsorption may occur due to low dietary fat content, even in the presence of an adequate supply of fat-soluble vitamins. Bile acids (BAs) have been confirmed as emulsifiers to promote fat absorption in high-fat diets. However, there are no direct evidence of exogenous BAs promoting the utilization of fat-soluble vitamins associated with fat absorption in vitro and in vivo. Therefore, we chose laying hens as model animals, as their diet usually does not contain much fat, to expand the study of BAs. BAs were investigated in vitro for emulsification, simulated intestinal digestion, and release rate of fat-soluble vitamins. Subsequently, a total of 450 healthy 45-week-old Hy-Line Gray laying hens were chosen for an 84-day feeding trial. They were divided into five treatments, feeding diets supplemented with 0, 30, 60, 90, and 120 mg/kg BAs, respectively. No extra fat was added to the basic diet (crude fat was 3.23%). In vitro, BAs effectively emulsified the water-oil interface. Moreover, BAs promoted the hydrolysis of fat by lipase to release more fatty acids. Although BAs increased the release rates of vitamins A, D, and E from vegetable oils, BAs improved for the digestion of vitamin A more effectively. Dietary supplementation of 60 mg/kg BAs in laying hens markedly improved the laying performance. The total number of follicles in ovaries increased in 30 and 60 mg/kg BAs groups. Both the crude fat and total energy utilization rates of BAs groups were improved. Lipase and lipoprotein lipase activities were enhanced in the small intestine in 60, 90, and 120 mg/kg BAs groups. Furthermore, we observed an increase in vitamin A content in the liver and serum of laying hens in the 60, 90, and 120 mg/kg BAs groups. The serum IgA content in the 90 and 120 mg/kg BAs groups was significantly improved. A decrease in serum malondialdehyde levels and an increase in glutathione peroxidase activity were also observed in BAs groups. The present study concluded that BAs promoted the absorption of vitamin A by promoting the absorption of fat even under low-fat diets, thereupon improving the reproduction and health of model animals.

Phenolic Release during In Vitro Digestion of Cold and Hot Extruded Noodles Supplemented with Starch and Phenolic Extracts

Dietary phenolic compounds must be released from the food matrix in the gastrointestinal tract to play a bioactive role, the release of which is interfered with by food structure. The release of phenolics (unbound and bound) of cold and hot extruded noodles enriched with phenolics (2.0%) during simulated in vitro gastrointestinal digestion was investigated. Bound phenolic content and X-ray diffraction (XRD) analysis were utilized to characterize the intensity and manner of starch-phenolic complexation during the preparation of extruded noodles. Hot extrusion induced the formation of more complexes, especially the V-type inclusion complexes, with a higher proportion of bound phenolics than cold extrusion, contributing to a more controlled release of phenolics along with slower starch digestion. For instance, during simulated small intestinal digestion, less unbound phenolics (59.4%) were released from hot extruded phenolic-enhanced noodles than from the corresponding cold extruded noodles (68.2%). This is similar to the release behavior of bound phenolics, that cold extruded noodles released more bound phenolics (56.5%) than hot extruded noodles (41.9%). For noodles extruded with rutin, the release of unbound rutin from hot extruded noodles and cold extruded noodles was 63.6% and 79.0%, respectively, in the small intestine phase, and bound rutin was released at a much lower amount from the hot extruded noodles (55.8%) than from the cold extruded noodles (89.7%). Hot extrusion may allow more potential bioaccessible phenolics (such as rutin), further improving the development of starchy foods enriched with controlled phenolics.

Digestion of protein and toxic gluten peptides in wheat bread, pasta and cereal and the effect of a supplemental enzyme mix.

There has been an increasing interest in the relationship between wheat digestibility and potential toxicity to the host. However, there is a lack of understanding about temporal profile of digestion of wheat proteins from different food matrices under physiologically relevant conditions. In this study, digestion of three wheat-based foods (bread, pasta and cereal) was conducted based on the INFOGEST semi-dynamic protocol in the absence and presence of a commercial supplemental enzyme preparation (a Glutalytic® based supplement, which will be marketed as Elevase®). Protein hydrolysis (OPA- ortho-phthalaldehyde - assay), molecular weight distribution (SEC-HPLC) and potential toxicity (R5 antibody-based competitive ELISA), were assessed. Our results demonstrated that under normal conditions, the complexity of the food influenced the temporal profile of protein hydrolysis and gluten breakdown throughout simulated gastric and intestinal digestion. However, treatment with the enzyme supplement significantly and acutely increased protein hydrolysis and gluten degradation in the gastric stage, and this enhanced digestion was maintained into the intestinal environment. These findings highlight the limitations of temporal gastric proteolysis and gluten degradation under normal conditions to different food types. They also show that supplemental enzyme mixes can effectively accelerate the breakdown of protein and hydrolysis of toxic gliadin fractions from the early stages of gastric digestion, thereby reducing intestinal exposure and potentially limiting the sensitization of the host.

Artificial simulated saliva, gastric and intestinal digestion and fermentation in vitro by human gut microbiota of intrapolysaccharide from Paecilomyces cicadae TJJ1213

In this study, the in vitro digestion and fermentation of two intra-polysaccharide fractions (IPS1 and IPS2) from Paecilomyces cicadae TJJ1213 were investigated. The constituent monosaccharides of IPS1 and IPS2 were not changed after simulated saliva, gastric and small intestinal digestion. However, they can be hydrolyzed and utilized by gut microbiota, and short-chain fatty acids (SCFAs) level were increased after IPS1and IPS2 treatments. Furthermore, 16S rRNA sequencing analysis of fermentation samples were performed. Alpha-diversity, beta-diversity and taxonomic composition differences analysis revealed that IPS1 and IPS2 promoted the proliferation of beneficial bacteria and modulated the overall structure of gut microbiota. Taxonomic comparison analysis found that IPS1 increased the relative abundances of beneficial bacteria including Megamonas, Bifidobacterium and Lactobacillus, while IPS2 could increase the abundance of Bacteroides, Parabacteroides and Phascolarctobacterium. In addition, they can also decrease the levels of pathogenic bacteria containing Escherichia-Shigella, Klebsiella and Fusobacterium. These results indicated that IPS from P. cicadae TJJ1213 could be used as potential candidates for new functional foods.

Bilosomes: A controlled delivery system for the sustained release of torularhodin during digestion in the small intestine both in vitro and in vivo

Torularhodin is a carotenoid with various biological activities, but its poor chemical stability and low bioavailability are obstacles to its usage. In this study, different small intestinal controlled delivery systems of torularhodin; including liquid-lip, liposomes, niosomes, and bilosomes; were prepared and characterized. Then, in vitro simulated gastrointestinal digestion model and in vivo mouse model were used to evaluate their sustained-release properties. Finally, mathematical models such as release kinetics revealed the release mechanisms of different systems. The results of particle size distribution and release rate of torularhodin indicated that both the liquid-lip and liposomes systems were almost completely digested after 2 h of simulated small intestinal digestion. However, the bilosomes system remained intact after simulated gastric digestion and were slowly cleaved during simulated small intestinal digestion with a sustained release effect of torularhodin. The fitting results of six kinetic models demonstrated that the kinetic mechanism of torularhodin release from bilosomes was a non-fickian mechanism. The main mechanism may be that bilosomes enhance the permeability of enterocyte biofilms by opening tight junctions between intestinal epithelial cells, thereby prolonging the release of torularhodin in the small intestine. Pharmacokinetic results in mice showed that the area under the concentration time curve in the bilosomes system was 2.73 times that of the liquid-lip system, and the t 1/2 was as long as 22.5 h, demonstrating that bilosomes system was an efficient delivery system for enhancing both the stability and bioavailability of torularhodin in the small intestine. These findings can be used to help future potential applications of bilosomes delivery systems for improving the bioavailability of carotenoids in food.

Release characteristics and bioaccessibility of lutein from calcium alginate hydrogels during simulated digestion in vitro

SummaryIn this study, the release of lutein from calcium alginate hydrogels during simulated digestion in vitro was investigated. The results showed that the cross‐linked hydrogel with Ca2+ concentration >7.5 mM had a large amount of lutein retained on the surface, and digestive enzymes caused rapid degradation of the hydrogel structure, resulting in a high initial release rate. The particle size of the digestate was the largest in the simulated small intestinal digestion stage, with the gradual degradation of the outer wall proteins of lutein nanoparticles, showing a decreasing trend in the colonic digestion stage. The hydrogel cross‐linked with high concentration of Ca2+ mainly released lutein nanoparticles with small particle size. In the later stage, the probability of agglomeration between lutein nanoparticles increased. The cumulative release rate of lutein in the hydrogel with Ca2+ concentration <7.5 mM was higher after digestion, but lutein retention was <80%. The formation of lutein mixed micelles was hindered by the hydrogel with a Ca2+ content more than 7.5 mM, and lutein bioaccessibility was reduced. As a result, appropriate concentration of Ca2+ cross‐linked hydrogel carrier improved lutein bioavailability while also extending the residence period.

The microbiome modulating potential of superheated steam (SHS) treatment of dietary fibres

In this study, wheat and oat bran fibres were used to investigate the potential beneficial prebiotic-enhancing effects of superheated steam (SHS) treatment. Following SHS treatment of fibres, in-vitro simulated gastric and intestinal digestion followed by batch culture fermentation was performed. 16S rRNA gene sequencing and short chain fatty acid analysis were conducted, which demonstrated that SHS treatment was associated with significant differences in beta diversity and the relative abundances of several microbial taxa. Principal Coordinate Analysis (PCoA) revealed significant separation between SHS-treated oat and non-treated oat (p = 0.013), and between SHS-treated wheat and non-treated wheat following in vitro batch fermentation (p = 0.042). Abundances of Ruminococcus were found to be significantly higher by 1.09-log in SHS-treated oat when compared with non-treated oat while abundances of Escherichia_Shigella, and Alistipes were significantly lower by 1.47-log and 0.39-log, respectively in the SHS-treated oat samples than the non-treated oat samples (p = 6.85E-06, p = 0.002037, p = 0.002458; respectively). These data demonstrate that SHS treatment of dietary fibre enhanced its effectiveness to modulate the gut microbiome.Industrial Relevance: Superheated steam (SHS) treatment has emerged as an effective method to improve the shelf-life of grains by reducing lipid hydrolysis and oxidation. Our results revealed that SHS treatment of wheat and oat brans led to increased physiological and chemical properties including higher water-binding capacity, water-extractable arabinoxylan, and total phenolics as well as improvement in human gut microbiota. Our results suggest that this method could be implemented in the food industry in order to improve beneficial properties of oat and wheat brans.

Fabrication of High-Acyl Gellan-Gum-Stabilized β-Carotene Emulsion: Physicochemical Properties and In Vitro Digestion Simulation

The β-carotene emulsion system using high-acyl gellan gum (HA) as an emulsifier was fabricated and systematically studied. The stability and stabilizing mechanism of the emulsion using medium-chain triglyceride as oil phase with a water-oil mass ratio of 9:1 under different physicochemical conditions of heat, pH, and ions were investigated by analyzing mean particle size (MPS), emulsion yield (EY), and dynamic stability. The effects of the HA-β-carotene emulsion system on the bioaccessibility of β-carotene in vitro were conducted. During the simulated oral digestion stage (SODP) and simulated gastric digestion stage (SGDP), the emulsion systems stabilized with different HA contents showed good stability, and the changes of MPS and zeta potential (ZP) were within 2.5 μm and 3.0 mV, respectively. After entering the simulated intestinal digestion phase (SIDP), β-carotene was released from oil droplets and formed micelles with bile salts, phospholipids, etc. HA-β-carotene emulsion can enhance the release rate of free fatty acid (FFA), which ultimately affects the β-carotene bioaccessibility. These results indicate that HA can be used to prepare carotene emulsion and improve its bioavailability. The study provides a reference for the application of HA as a natural emulsifier and the delivery of β-carotene.

Impact of Low-Temperature Storage on the Microstructure, Digestibility, and Absorption Capacity of Cooked Rice.

This study examined the effects of low-temperature storage on the microstructural, absorptive, and digestive properties of cooked rice. Cooked rice was refrigerated and stored at 4 °C for 0.5, 1, 3, 5, and 7 days, as well as frozen and preserved at −20, −40, and −80 °C for 0.5, 1, 3, 5, 7, 14, 21, and 28 days. The results indicated that the stored rice samples generally exhibited a higher absorption capacity for oil, cholesterol, and glucose than the freshly cooked rice. In addition, after storage, the digestibility of the cooked rice declined, namely, the rapidly digestible starch (RDS) content and estimated glycemic index (eGI) decreased, whereas the slowly digestible starch (SDS) and resistant starch (RS) content increased. Moreover, the increment of the storage temperatures or the extension of storage periods led to a lower amylolysis efficiency. Scanning electron microscopy (SEM) analysis indicated that storage temperature and duration could effectively modify the micromorphology of the stored rice samples and their digestion. Moreover, microstructural differences after storage and during simulated intestinal digestion could be correlated to the variations in the absorption capacity and digestibility. The findings from this study will be useful in providing alternative storage procedures to prepare rice products with improved nutritional qualities and functional properties.

The Caco-2 Cell Bioassay for Measurement of Food Iron Bioavailability.

Knowledge of Fe bioavailability is critical to the assessment of the nutritional quality of Fe in foods. In vivo measurement of Fe bioavailability is limited by cost, throughput, and the caveats inherent to isotopic labeling of the food Fe. Thus, there exists a critical need for an approach that is high-throughput and cost-effective. The Caco-2 cell bioassay was developed to satisfy this need. The Caco-2 cell bioassay for Fe bioavailability utilizes simulated gastric and intestinal digestion coupled with culture of a human intestinal epithelial cell line known as Caco-2. In Caco-2 cells, Fe uptake stimulates the intracellular formation of ferritin, an Fe storage protein easily measured by enzyme-linked immunosorbent assay (ELISA). Ferritin forms in proportion to Fe uptake; thus, by measuring Caco-2 cell ferritin production, one can assess intestinal Fe uptake from simulated food digests into the enterocyte. Via this approach, the model replicates the key initial step that determines food Fe bioavailability. Since its inception in 1998, this model approach has been rigorously compared to factors known to influence human Fe bioavailability. Moreover, it has been applied in parallel studies, with three human efficacy studies evaluating Fe biofortified crops. In all cases, the bioassay correctly predicted the relative amounts of Fe bioavailability from the factors, crops, and overall diet. This paper provides detailed methods on Caco-2 cell culture coupled with the in vitro digestion process and cell ferritin ELISA necessary to conduct the Caco-2 cell bioassay for Fe bioavailability.

Antioxidant Potential of Selected Wild Edible Leafy Vegetables of Sikkim Himalayan Region: Effects of Cooking Methods and Gastrointestinal Digestion on Activity.

Green leafy vegetables or GLVs are one of the main attractions in the local vegetable market and are widely consumed as the main course and side dish in the Sikkim Himalayan region (SHR). This study evaluated the total phenolic (TPC) and flavonoid contents (TFC) and antioxidant potential in different extracts such as methanolic (MeOH), ethyl acetate (EtOAC), and hexane extracts of selected GLVs followed by changes in the antioxidant activity on cooking and stimulated gastrointestinal (GI) digestion. The MeOH extracts of Urtica dioica L. (Sisnu), Nasturtium officinale W. T. Aiton (Simrayo), Diplazium esculentum Retz. Sw. (Ningro), and Chenopodium album L. (Bethu) were estimated to have higher TPC [22.73–45.84 μg gallic acid equivalent (GAE)/mg of extract]. In contrast, the plant extracts prepared using EtOAC (except for N. officinale, where TFC was found to be higher in hexane extract) were found to contain higher TFC (3.42–14.86 μg quercetin equivalent (QE)/mg of extract). The MeOH extracts also exhibited higher 2, 2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity (9.55–18.67 μg ascorbic acid equivalent (AAE)/mg of extract), total antioxidant activity (TAA) (0.27–0.32 mg AAE/mg of extract), and reducing power potential (RPP) (1.6–9.9 μg AAE/mg of extract). Among the test MeOH extracts, U. dioica demonstrated relatively higher antioxidant activities and was selected for cooking experiments followed by simulated GI digestion. The findings revealed that the loss of antioxidant activity was minimal in steam-cooked leaves (3.5% in 40 min) as compared to the boiled ones (18% in 10 min). The simulated GI (simulated salivary, gastric, and intestinal) digestion performed on raw, steam cooked, and boiled U. dioica leaves showed substantial enhancement of antioxidant properties (by 64.63%) through steam cooking in comparison to the raw leaves. Overall the study concludes that higher antioxidant properties can be achieved on the consumption of steam-cooked U. dioica leaves.

Preparation of novel self-assembled albumin nanoparticles from Camellia seed cake waste for lutein delivery

The potential utilization value of Camellia seed cake was explored by extracting albumin (CSCA) to develop nanoparticles for lutein delivery. First, thermal property and amphiphilicity of CSCA were evaluated to guide nanoparticle preparation. Next, CSCA nanoparticles modified with chitosan (CS) were prepared through a thermally induced self-assembly method derived by electrostatic attraction and hydrophobic interaction. The optimized nanoparticles were prepared from CSCA:CS at a mass ratio of 2:1 with pH of 4.5, and an incubation temperature and time of 80 ℃ and 10 min, respectively. The nanoparticles had the highest effective loading capacity for lutein at 5.89 ± 0.78%, and the corresponding encapsulation efficiency was 43.82 ± 5.69%. The storage stability of lutein was improved by nanoparticle loading, and the bioaccessibility of lutein in simulated intestinal digestion increased from 26.8 ± 4.4% to 57.3 ± 9.6% after encapsulation into nanoparticles. These findings may facilitate the development of new and sustainable proteins from plant waste for delivery system applications.