Intestinal Phase Research Articles

The stability and digestion properties of nobiletin in emulsion gel based on RG-I type citrus physiological premature fruit drop pectin

Based on the fact that rhamnogalacturonan I (RG-I) type pectin gels have good digestive resistance to the stomach and small intestine, which is only degraded to the colon, as well as the good anti-colon cancer effect of nobiletin. In this study, emulsion gel of five different oil phase types (soybean oil, peanut oil, corn oil, sunflower oil and medium chain triglyceride (MCT)) were prepared using RG-I type citrus physiological premature fruit drop pectin (CPDP) as a substrate for in vitro simulated digestion experiments to investigate the delivery effect on nobiletin. The results showed that the bioaccessibility of nobiletin in soybean oil emulsion gel was lower in the small intestine phase relative to emulsion gel prepared with other oils, which was related to the higher saturated fatty acid content of soybean oil and the higher gel strength of soybean oil emulsion gel. Relative to the emulsion, the emulsion gel showed higher retention and lower bioaccessibility of nobiletin in the small intestine phase. Moreover, the centrifugal stability and thermal stability of nobiletin in the emulsion gel were higher than that of the emulsion, and the emulsion gel was stable in the pH range of 2–7 without delamination. In conclusion, the emulsion gel system prepared with RG-I type CPDP may be well suited for the colon targeted delivery of nobiletin, especially when soybean oil is the oil phase, which provides consideration for colon cancer resistance.

In vitro protein digestibility of RuBisCO from alfalfa obtained from different processing histories: Insights from free N-terminal and mass spectrometry study

Ribulose-1,5-bisphosphate-carboxylase/oxygenase (RuBisCO) from alfalfa is a potentially climate-friendly alternative protein with a promising amino acid composition. The balance between yield and purity is a challenge for alternative plant proteins, partly due to the naturally occurring antinutrients. Therefore, measuring the in vitro protein digestibility (IVPD) of RuBisCO with various purity levels is of interest. It was hypothesized that the digestibility of RuBisCO from alfalfa might vary with different processing histories and levels of refinement. To test this hypothesis, RuBisCO from alfalfa with 4 different processing histories were subjected to the INFOGEST IVPD protocol and measurement of free N-terminals and peptidomics. The result showed that the digestibility of RuBisCO was high regardless of the processing history and purity, as demonstrated by 77–99% sequence coverage in the gastric phase. In intestinal phase, increase of free N-terminals and lower sequence coverage (< 10%) indicated that the proteins were hydrolyzed to smaller peptides.

Effect of Salt Stress on the Phenolic Compounds, Antioxidant Capacity, Microbial Load, and In Vitro Bioaccessibility of Two Microalgae Species (Phaeodactylum tricornutum and Spirulina platensis).

Microalgae have gained attention as alternative food sources due to their nutritional value and biological effects. This study investigated the effect of salt stress on the antioxidant activity, phenolic profile, bioavailability of bioactive compounds, and microbial counts in the blue-green algae Spirulina platensis and diatom species Phaeodactylum tricornutum. These microalgae were cultured in growth mediums with different salt concentrations (15-35‱) We observed the highest antioxidant activity and phenolic compounds in the control groups. S. platensis (20‱) exhibited higher antioxidant activity compared to P. tricornutum (30‱), which decreased with increasing salt stress. Using HPLC-DAD-ESI-MS/MS, we identified and quantified 20 and 24 phenolic compounds in the P. tricornutum and S. platensis culture samples, respectively. The bioavailability of these compounds was assessed through in vitro digestion with the highest amounts observed in the intestinal phase. Salt stress negatively affected the synthesis of bioactive substances. Microbial counts ranged from 300 to 2.78 × 104 cfu/g for the total aerobic mesophilic bacteria and from 10 to 1.35 × 104 cfu/g for yeast/mold in P. tricornutum samples while the S. platensis samples had microbial counts from 300 to 1.9 × 104 cfu/g and the total aerobic mesophilic bacteria from 10 to 104 cfu/g, respectively. This study suggests that adding salt at different ratios to the nutrient media during the production of P. tricornutum and S. platensis can impact phenolic compounds, antioxidant capacity, microbial load evaluation, and in vitro bioaccessibility of the studied microalgae.

Development of a Chicken Gastrointestinal Tract (GIT) Simulation Model: Impact of Cecal Inoculum Storage Preservation Conditions

A chicken gastrointestinal tract (GIT) simulation model was developed to help predict the potential effects of feed additives supplementation on chicken’ microbiota. The chemical and enzymatic conditions for oral, gastric, intestinal, and cecum fermentation phases were designed to closely resemble the chicken GIT conditions. For cecum fermentation, the inoculum was obtained from the cecal contents of 18 38-day broiler chickens. The impact of inoculum preservation on bacteria viability was assessed by comparing two methods of preservation with fresh inoculum: (1) 5% dimethyl sulfoxide (DMSO) at −80 °C and (2) 30% glycerol at −20 °C. The fermentation with fresh and frozen (DMSO method) inoculums was performed and compared using standard chicken feed (SCF) and SCF with 1% fructooligosaccharides (FOS), and inoculum control (IC) condition without feed matrix was used as a baseline. Inoculum’s viability was assessed throughout 90 days of storage by culture media platting, while bacterial growth and metabolites production during fermentation was evaluated by quantitative polymerase chain reaction (qPCR), high-performance liquid chromatography (HPLC), and total ammonia nitrogen quantification. The DMSO method was shown to be the most suitable for cecal inoculum storage. Higher growth of beneficial cecal bacteria for fresh inoculum was observed in SCF while for frozen inoculum, was the SCF + FOS condition. Also, frozen inoculum had lower activity of butyrate producers and proteolytic bacteria, showing different fermentation profiles. The GIT model developed showed to be useful to test the effect of feed additives supplementation.

Selenium contents, speciation and bioaccessibility of Se-enriched rice grains from Chinese markets

Diet intake accounts for >90% of selenium (Se) exposure in humans, with rice being the main source of Se intake for >60% of the Chinese population. In this study, 48 rice grain samples labeled Se-enriched were obtained from 22 major rice producing areas in China through online sources. Their total Se contents, Se speciation, and Se bioaccessibility were evaluated to provide a holistic view of Se-enriched rice in the market. The total Se contents were 0.006–0.951 ​μg ​g−1 (average 0.249 ​μg ​g−1), which showed great regional variations, with 73% of the samples satisfying the Se-enriched standard based on GB/T22499-2008 (0.04–0.30 ​mg ​kg−1). Over 80% of Se in the rice samples was organic Se species including selenomethionine, selenocysteine and methylselenocysteine, with selenomethionine being the main Se species, accounting for 61–98%. Based on a modified physiologically-based extraction test (MPBET), the Se bioaccessibility in 33 selected samples was 8.05–49.6% (28.6%) in the gastric phase and 18.1–117% (82.5%) in the intestinal phase. Further, Se bioaccessibility was positively correlated with organic Se (r ​= ​0.89–0.93), but not with inorganic Se (selenite and selenate), suggesting that Se bioaccessibility depended on organic Se in these rice grains. The data call for re-evaluation of Se-enriched rice in the market. Further, the potential risk of long-term consumption of Se-enriched rice in the market towards human health should be studied.

Fate of Amadori compounds in processing and digestion of multi-ingredients tomato based sauces and their effect on other microconstituents

Amadori compounds (ACs), the first stable products of Maillard reaction, are detected in various products of fruits and vegetables, and show an antioxidant activity which can be related to beneficial effects in human health. In order to optimize the nutritional quality of a multi-ingredient tomato sauce (tomato puree – onion – olive oil – dried pepper), the fate of ACs during processing (drying, heating) and gastrointestinal digestion of a model meal was assessed as well as that of other microconstituents, i.e. carotenoids, phenolic compounds and capsaicinoids. The drying at 50 °C of fresh pepper induced the formation and accumulation of ACs after 6 days. During the heat treatment by microwave of multi-ingredient tomato sauce, Maillard reaction occurs in presence of dried pepper and the content in ACs in the tomato-based sauces increased (+33% to + 53%) depending of quantities of dried pepper added. The bioaccessibility of total ACs was 24–31% in duodenal phase and 18–22% in jejunal phase. Individual ACs have shown variable bioaccessibility, e.g. very high for Fru-Arg (50.8% to 71.3%), and very low for Fru-Met (1.8% to 2.2%). The kinetic monitoring of ACs in digestion medium showed that ACs are not stable (-46% in gastric phase, −49 % in intestinal phase) which indicated their potential degradation in the digestive tract. The presence of ACs in the multi-ingredients tomato sauces had no effect on the content of the other bioactive compounds monitored in the study and even promoted the bioaccessibility of total lycopene (+30%) but decreased the bioaccessibility of total phenolic compounds.

Influence of Encapsulation of Propolis Extract with 2-Hydroxypropyl-β-cyclodextrin (HP-β-CD) on Polyphenolic Contents during In Vitro Simulation of Digestion

Studies of polyphenols in various natural products have shown their variability and often low amounts. Thus, we aimed to investigate the bioaccessibility of the main polyphenolic groups extracted from two poplar types of propolis collected in continental Croatia. The propolis complex, in the form of water-soluble powder of propolis extract with the carrier 2-hydroxypropyl-β-cyclodextrin (HP-β-CD), was obtained by applying ultrasonic-assisted extraction followed by lyophilization. The in vitro gastrointestinal digestion was conducted on the propolis complex extracts and a mixture of standards (pinocembrin, galangin, chrysin, caffeic acid, and caffeic acid phenylethyl ester). Fractions from the oral, gastric, and intestinal phase samples were analyzed spectrophotometrically by standard methods used to determine the content of total phenols (TPs), flavonols/flavones (TFFs), and flavanones/dihydroflavonols (TFDs). The small-intestinal phase was performed by two models: centrifugation and dialysis. The results of propolis-HP-β-CD extracts demonstrated high polyphenolic bioaccessibility during all three phases of digestion. The bioaccessibility of TPs, TFFs, and TFDs after the intestinal phase with centrifugation was from 0.02 to 8.86 times higher than in the dialysis phase, stressing that it is a better model than dialysis. Our findings show that the inclusion complex of propolis with HP-β-CD enables the good solubility of polyphenol groups.

Milk protein-based cryogel monoliths as novel encapsulants of probiotic bacteria. Part II: Lacticaseibacillus rhamnosus GG storage stability and bioactivity under in vitro digestion

The aim of the study was to assess the ability of milk protein-based cryogel monoliths to preserve the biological activity of Lacticaseibacillus rhamnosus GG (LGG) under cryogenic processing, temperature – aw controlled storage and under in vitro gastrointestinal conditions. The cryogelation process did not result in any significant cellular injuries (losses < 0.5 logCFU.g−1) due to the achievement of a vitreous state under the cryogenic conditions implemented. Among the tested storage conditions, temperature was the most impactful parameter on LGG inactivation rates (kLGG = 0.002−0.008 to 0.25−0.56 day−1 for 5 and 37 °C, respectively), followed by protein composition (i.e. the presence of sodium caseinate alleviated the lethality of LGG). Glassy cryogels stored at aw ≤ 0.33 enabled good LGG survivability (kLGG 0.033−0.045 day−1) compared to their rubbery analogues (i.e. aw > 0.33). The cryogels exhibited limited disintegration during gastric processing, which aided LGG cells to resist gastric stressors, while complete disintegration occurred during the intestinal step, facilitating the release of LGG cells and promoting the cryogel matrix's digestibility (>64%). LGG counts in the intestinal phases remained high (>8.2 logCFU.g−1), and the peptidomic profiling confirmed the release of bioactive peptides including angiotensin-converting enzyme and dipeptidyl peptidase-4 inhibitory, antimicrobial, and antioxidant peptides.

Effects of Lactiplantibacillus plantarum with different phenotypic features on the nutrition, flavor, gel properties, and digestion of fermented soymilk

This study evaluated the effects of four previously reported strains of Lactiplantibacillus plantarum (T1, CL80, CSK, and S-1A) with different phenotypic characteristics on the fermentation quality, flavor characteristics, and digestive properties of soy milk. The results showed that all four strains exhibited good gastrointestinal survival and Caco-2 cell adhesion probiotic characteristics. The total free amino acid content of fermented soy milk significantly increased from 27.57 mg/100 g to 41.28 mg/100 g, enriching the soy milk with acidity and increasing the volatile flavor compounds such as acetic acid, decanoic acid, and octanoic acid. The fermentation process effectively reduced the levels of volatile compounds associated with beany off-flavors, including 1-octen-3-ol, 1-nonanol, hexanal, heptanal, 2-octenal, furfural, and trans-2,4-decadienal. The gel texture and rheological analysis indicated that soy milk fermented with the viscous phenotypic strains T1 and CL80 exhibited higher water-holding capacity (95.45%, 93.64%) and apparent viscosity (916.39, 713.78 Pa s). Furthermore, in vitro dynamic digestion demonstrated that soy milk fermented with the viscous phenotypic strains was more easily digested during the gastric phase compared to the non-viscous strains. In the intestinal phase of digestion, soy milk fermented with the ropy phenotypic strains had significantly higher levels of small peptides compared to the non-ropy strains, which facilitated the transfer and absorption of nutrients. This study provides valuable insights into improving the nutritional flavor and digestive properties of soy milk through fermentation using Lactiplantibacillus plantarum strains with different phenotypic characteristics.

Encapsulation of purple basil leaf extract by electrospraying in double emulsion (W/O/W) filled alginate-carrageenan beads to improve the bioaccessibility of anthocyanins

The purple basil leaf extract (PBLE) was encapsulated in double emulsion (W1/O/W2)-loaded beads (emulgel) by electrospraying. The influence of κ-carrageenan (κ-CG) and cross-linking agents (Ca2+/K+) on the properties of alginate (SA) beads were assessed. In emulgel beads, κ-CG inclusion resulted in larger sizes and more distorted shapes, wrinkles on the surface, and lower gel strength. The encapsulation efficiency of anthocyanins (ACNs) in emulgel beads ranged from 70.73 to 87.89 %, whereas it ranged from 13.50 to 20.67 % in emulsion-free (hydrogel) beads. Fourier transforms infrared (FTIR) revealed the crosslinking of SA and κ-CG with Ca2+ and K+, thermogravimetric analysis (TGA), derivative thermogravimetric (DTG), and differential scanning calorimetry (DSC) thermograms showed emulgel beads yielded higher thermal stability. The emulgel beads elevated the in vitro bioaccessibility of ACNs under simulated digestion. At the gastric phase, 86 % of ACNs in PBLE, and 46 % of loaded ACNs in hydrogel beads were released, whereas no release was occurred in emulgel beads. At the intestinal phase, after 150 min of digestion, no ACNs were detected in PBLE and hydrogel beads, whereas all emulgel beads continued to release ACNs until 300 min. The incorporation of double emulsions in hydrogel beads can be utilized in the development of functional foods.

Simulated gastrointestinal digestion of polylactic acid (PLA) biodegradable microplastics and their interaction with the gut microbiota

The accumulation of microplastics (MPs) in the environment as well as their presence in foods and humans highlight the urgent need for studies on the effects of these particles on humans. Polylactic acid (PLA) is the most widely used bioplastic in the food industry and medical field. Despite its biodegradability, biocompatibility, and “Generally Recognized As Safe” (GRAS) status, recent animal model studies have shown that PLA MPs can alter the intestinal microbiota; however, to date, no studies have been reported on the possible gut and health consequences of its intake by humans. This work simulates the ingestion of a realistic daily amount of PLA MPs and their pass through the gastrointestinal tract by combining the INFOGEST method and the gastrointestinal simgi® model to evaluate possible effects on the human colonic microbiota composition (16S rRNA gene sequencing analysis) and metabolic functionality (lactic acid and short-chain fatty acids (SCFA) production). Although PLA MPs did not clearly alter the microbial community homeostasis, increased Bifidobacterium levels tended to increase in presence of millimetric PLA particles. Furthermore, shifts detected at the functional level suggest an alteration of microbial metabolism, and a possible biotransformation of PLA by the human microbial colonic community. Raman spectroscopy and field emission scanning electron microscopy (FESEM) characterization revealed morphological changes on the PLA MPs after the gastric phase of the digestion, and the adhesion of organic matter as well as a microbial biofilm, with surface biodegradation, after the intestinal and colonic phases. With this evidence and the emerging use of bioplastics, understanding their impact on humans and potential biodegradation through gastrointestinal digestion and the human microbiota merits critical investigation.

Size exclusion chromatography to evaluate in vitro proteolysis: A case study on the impact of microstructure in pulse powders.

Cellular pulse ingredients are increasingly being studied but little knowledge on their proteolysis patterns upon digestion is available. This study investigated a size exclusion chromatography (SEC) approach to study in vitro protein digestion in chickpea and lentil powders, providing novel insights into proteolysis kinetics and the evolution of molecular weight distributions in the (solubilized) supernatant and (non-solubilized) pellet fractions. For the quantification of proteolysis, SEC-based analysis was compared to the commonly used OPA (o-phthaldialdehyde) approach and nitrogen solubilized upon digestion, leading to highly correlated proteolysis kinetics. Generally, all approaches confirmed that microstructure dictated proteolysis kinetics. However, SEC analysis delivered an additional level of molecular insight. For the first time, SEC revealed that while bioaccessible fractions reached a plateau in the small intestinal phase (around 45-60min), proteolysis continued in the pellet, forming smaller but mostly insoluble peptides. SEC elutograms showed pulse-specific proteolysis patterns, unidentified using other current state-of-the-art methods.

Assessment of heavy metal contamination in street dust: concentrations, bioaccessibility, and human health risks in coal mine and thermal power plant complex.

Coal mining has also been associated with adverse environmental and health impacts including cancer and respiratory disorders, with the presence of thermal power plants exacerbating the problem of heavy metal pollution. Minimal studies have been conducted on the environmental impacts, health risks, and bioaccessibility of heavy metals in coal mine areas. Consequently, samples of street dust were collected from different locations in the Singrauli mine complex and analysed. Heavy metals (Cu, Ni, Zn, Cr, Co, As, and Mo) were found to be higher than the background concentration, with the maximum concentration was found in areas close to the Thermal Power Plants, like Near Vindyachal TPP, Near Shakti Nagar TPP, and Anpara. The highest geo-accumulation index value was found for Co, Mo, Zn, and As, indicating moderate to strong pollution levels. Health risk assessment (for both adults and children) revealed that Cr and Fe posed significantly higher Hazard Quotient and Hazard Index (HI) values, indicating significant non-carcinogenic threats. Moreover, Carcinogenic Risk (CR) values for Cd, Cr, and Ni indicated a risk of carcinogenicity to the public exposed to road dust. The study also examined the bioaccessibility of the metals, which showed that the gastric phase accumulated a higher percentage of Ni (42.52%), Pb (34.79%), Co (22.22%), As (20%) and Cu (15%) than the intestinal phase. Strong positive correlation was observed between metal concentration (Cu, Pb, Cr, Fe, Zn, and Mn), HI, and CR of adult and child, while bioaccessibility of intestinal phase was positively correlated with gastric phase of metals (Cu, Ni, Co, As, and Mn).

Polyphenol Bioaccessibility and Antioxidant Activity of Pomegranate (Punica granatum) Peel Supplementation in Diet-Induced Obese Rats.

Fruit by-products are a source of biocompounds with antioxidant properties and potential role in the obesity treatment. This study aimed to assess the effect of pomegranate (Punica granatum) peel (PP) supplementation on the total antioxidant capacity (TAC) in diet-induced obese rats. Thus, an in vitro gastrointestinal digestion was performed to evaluate the total phenolic content (TPC) and the antioxidant capacity of PP. Moreover, 15 male Wistar rats were randomized into three groups: control diet (CTL; 3.35 kcal/g), cafeteria (CAF) diet (3.72 kcal/g), and CAF diet supplemented with PP (CAF + PP; 200 mg/kg body weight; 3.72 kcal/g). Serum TAC was analyzed by ferric reducing antioxidant power and 2,2-Diphenil-1-picrylhydrazil assay. TPC in PP accounted for 8.82 ± 0.14 mg GAE/g in undigested samples. However, an in vitro digestion process was decreased by 94% the bioaccessibility of PP phenolic compounds in the intestinal phase, while PP supplementation increased serum TAC in diet-induced obese rats. Therefore, although PP phenolic compounds diminished after an in vitro digestion process, antioxidant effect was found in obese rats supplemented with PP.

Effects of foods and food components on the in vitro bioaccessibility of total arsenic and arsenic species from Hizikia fusiforme seaweed

Seaweed is an important food source, especially in many Asian countries, because of its high nutritional value; however, increasing arsenic (As) accumulation may pose serious hazards to human health. The influence of food components on As bioaccessibility and transformation in the high As-containing seaweed Hizikia fusiforme was determined using an in vitro gastrointestinal digestion method. The results showed that co-digestion with several daily foods (such as celery, broccoli, onion, green chili, tomato) produced a higher As bioaccessibility (approximately 6–11 % increase) compared with that of seaweed alone. Vegetables such as fennel (Foeniculum valgare Mill.), celery (Apium grareolens L.), blanched garlic leaves (Allium sativum L.), scallions (Allium fistulosum L.), ginger (Zingiber officinale Rosc.), and green pepper (Capsicum frutescens L. vat. grussum Bailey) decreased bioaccessible inorganic As (18–35 %) in both the gastric and small intestinal phases. Meanwhile, the process of reducing As(V) to As(III) also occurred during co-digestion with some food matrices. Egg white and other animal proteins were the most effective reducing agents, transforming >70 % As(V) into As(III) in the solution system. These results may have important implications for health risk assessment via co-consumption. The present study provides the first evidence showing that the co-consumption of some vegetables and proteins leads to a higher toxicity of inorganic arsenic-containing food. In addition, the positive and negative effects of co-digestion on the bioaccessibility of essential metals (iron, manganese) compared to single digestion were evaluated in this study.

Bioactive Phenolic Compounds from Apples during Simulated In Vitro Gastrointestinal Digestion: Kinetics of Their Release

Bioactive phenolic compounds in their natural form show beneficial effects on the gastrointestinal system. The kinetics of their release are important for understanding those effects. The aim was to study the kinetics of the release of phenolic compounds from apples during in vitro simulated gastrointestinal digestion by using modified equations of first- and second-order kinetics. 35% and 67% of total phenolic compounds were released in the gastric phase, and 26% and 27% in the intestinal phase (peel and flesh, respectively). Intensive release of anthocyanins, flavan-3-ols, dihydrochalcones, phenolic acids, and flavonols occurred in the first 10 min of gastric digestion. In intestinal digestion, flavan-3-ols and anthocyanins were not identified; the dihydrochalcone amount decreased, while phenolic acids and flavonols showed stability. Concentrations at the endpoint of the release (c∞) were determined with kinetic equations fitted well to the experimental data (cexp) (r2 = 0.9973 and 0.9946 for first- and second-order). The half-life for released phenolic subgroups in gastric digestion was up to 3.5 (first-order kinetics) or 2.5 min (second-order), or in intestinal digestion up to 20.9 (first-order) or 32.3 min (second-order). Modified equations reported here for the first time fit well with the experimental data.

Fabrication of rice bran oil nanoemulsion and conventional emulsion with Mustard Protein Isolate as a novel excipient: Focus on shelf-life stability, lipid digestibility and cellular bioavailability

Proteins are one of the many effective biomolecules found in oilseed meals. In order to formulate an oil-in-water nanoemulsion based lipophilic nutraceutical delivery vehicle for Rice Bran oil (RBO) rich in γ-oryzanol, we used mustard seed meal protein isolate (MPI) as a novel natural surfactant together with a small molecular weight co-surfactant Tween 20 in various ratios (3:1, 1:1, 1:3) to stabilize the heterogeneous system. The oxidative stability, physico-chemical characterization in response to pH and ionic strength, shelf-life, and storage of the nanoemulsions containing 1% surfactant in total, comprising different ratios of MPI and Tween 20 were optimised to form an efficient biphasic surfactant system. The oil-in-water nanoemulsions fabricated utilizing high energy approach, i.e. high pressure homogenisation method was found to reduce dispersed phase particles size in the range of 150–160 nm. Minimal non-significant variation in droplet size and surface charge over the 8 weeks storage periods proves their excellent shelf-life stability. The use of MPI as surfactant for the delivery system also increased the lipid fraction digestibility releasing 70% of the fatty acids from dispersed phase oil droplets in simulated intestinal phase of three step in vitro digestion of nanoemulsion as compared to its conventional counterpart. The γ-oryzanol rich nanoemulsions improved prophylactic effectiveness against ROS in terms of overall cell survival and cell membrane integrity. The results will pave new domains to use MPI as surface active agents for delivery system formulation enriched with nutraceuticals and phytochemicals possessing superior functional advantages, bioavailability and antioxidative potentials.

Lowered oral bioaccessibility of cadmium and selenium and associated health risk by co-digestion of rice and vegetables

Since foods are not ingested individually, co-digestion, in accordance with human daily diet conditions, should be stressed when assessing elements bioaccessibility and associated health risks. The oral bioaccessibility of cadmium (Cd) and selenium (Se) in 11 types of crops (rice, maize, pakchoi, eggplant, red pepper, towel gourd, kidney bean, soybean, cowpea, sweet potato, and taro) were determined, and the effects of co-digestion of 7 types of rice and vegetables on the bioaccessibility of Cd and Se were evaluated and validated with in vitro PBET method. The underlying mechanism was revealed by observing the surface morphological characteristics of digested substrates, and the exposure risk of Cd and Se were assessed. The results showed that the average bioaccessibility of Cd and Se in 11 types of crops varied from 58.7 % to 39.1 % and 48.4 % to 62.6 % from the gastric phase (GP) to the intestinal phase (IP). Interestingly, co-digestion of rice and vegetables reduced the bioaccessibility of Cd and Se to varying degrees compared to theoretical values. Great reduction in the bioaccessibility of Cd and Se in the GP (16.9–36.4 % and 9.9–23.2 %) than that in the IP (0.2–6.62 % and 0.23–12.3 %) were detected, which was attributed to the rice–vegetable aggregates formed during co-digestion. Rice–vegetable aggregates inhibited the release of Cd and Se, which was more pronounced in the GP than in the IP. Consequently, co-digestion of rice and vegetables reduced the oral exposure to Cd by 35.8 % and to Se by 19.6 %. The areas with higher non-carcinogenic risk of Cd and Se in the study region were reduced by 17 % and 10 %, respectively. Therefore, the role of co-digestion in assessing Cd and Se bioaccessibility and associated health risk cannot be neglected. This study has significant implications for investigating elements bioaccessibility and optimizing associated health risk assessment from a novel perspective.

Using mid‐infrared spectroscopy combined with chemometrics to determine digested starch and maltose concentration during in‐vitro digestion of starches

SummaryStarch digestion is typically evaluated using in‐vitro techniques. During and after the in‐vitro digestion, samples are collected (gastric and intestinal phases) at allotted time intervals where starch digestion is quantified through the analysis of sugars using routine chemical and enzymatic analysis. This paper reports the use of mid‐infrared (MIR) spectroscopy as rapid method to measure the concentration of maltose and % digested starch during the digestion of rice and potato starch, maize starch namely Gelose 50 (50% amylose), Gelose 80 (80% amylose) and pregelatinized corn starch collected at different time points (5, 10, 15, 20, 25, 30, 40, 50, 60, 75, 90, 105 and 120 min) from two in‐vitro digestion experiments. Two types of samples, turbid and supernatant were also evaluated. The coefficient of determination (R2) and the standard error in cross‐validation (SECV) ranged between 0.74 to 0.93 and 163 to 360 μg mL−1 for the prediction of the concentration of maltose. The use of turbid samples showed a better predictive ability when compared with the regression models developed using the supernatant samples. This method showed potential to significantly decrease the time and effort associated to determining maltose concentration and % digested starch during in‐vitro digestion.

A comparative study on the physicochemical characteristics and protein digestibility of tofu induced by magnesium chloride or combined with transglutaminase

SummaryIn this study, tofu was prepared through the addition of transglutaminase (TGase) for pre‐crosslinking at varying durations (1, 2 and 3 h), followed by the addition of magnesium chloride (MgCl2) to soymilk. The physicochemical properties and protein digestibility were analysed. Results indicated that, with the prolongation of TGase pre‐crosslinking time, the zeta‐potential absolute value and the average particle size of soymilk increased gradually. In contrast, the pH value remained unchanged (P &gt; 0.05), suggesting that the colloidal stability of soymilk improved with TGase treatment. Both the water‐holding capacity (WHC) and gel strength of tofu gels exhibited a first increasing and then decreasing trend with prolonged pre‐crosslinking time. Notably, the highest WHC and hardness values of tofu gels prepared by adding MgCl2 after pre‐crosslinking with TGase for 1 h were 96.5 ± 0.5% and 363.9 ± 28.3 g, respectively. Subsequently, in vitro simulated gastrointestinal digestion of tofu samples prepared under this condition was conducted to determine changes in soluble protein content, small peptide content and protein hydrolysis spectrum. Gastric and intestinal digestion phases were the primary stages of protein hydrolysis, and the bioavailability of proteins in TGase+MgCl2‐induced tofu was higher than in MgCl2‐coagulated tofu. Therefore, tofu prepared through TGase pre‐treatment was more conducive to soybean protein digestion and absorption.