Simulated Gastrointestinal Digestion Research Articles

Bioactivity and influence on colonic microbiota of polyphenols from noni (Morinda citrifolia L.) fruit under simulated gastrointestinal digestion

Noni (Morinda citrifolia L.) is a tropical fruit rich in bioactive compounds. Little is known about its polyphenol composition at different ripeness levels and digestive characteristics. Here, we studied changes in polyphenols and antioxidant activity as noni ripened. Rutin and kaempferol-3-O-rutinoside were found in high amounts in noni, with antioxidant capacity increasing as it ripened. Under simulated digestion, polyphenols were gradually released from the oral to gastrointestinal phases, partially decomposing in the small intestine due to their instability. Conversely, fiber-bound phenols were released during colonic fermentation, leading to high bioaccessible antioxidant activity. Additionally, noni consumption affected the intestinal microbiome by reducing the Firmicutes/Bacteroidetes ratio and increasing bacteria with prebiotic properties like Prevotella and Ruminococcus. These findings demonstrate that polyphenols significantly contribute to the health benefits of noni fruit by providing absorbable antioxidants and improving the structure of the intestinal microbiome.

Exploring the Chemical Composition of Female Zucchini Flowers for Their Possible Use as Nutraceutical Ingredient.

The zucchini (Cucurbita pepo L.) plant is well known for its fruits; however, its edible flowers appear to contain several active molecules, including polyphenols, which display poor bioaccessibility after gastrointestinal digestion (GiD). This study explores the bioaccessibility of polyphenols and antioxidant capacity within zucchini flower extracts during simulated GiD. Two nutraceutical formulations, non-acid-resistant (NAcR) and acid-resistant (AcR) capsules containing an aqueous extract of zucchini flowers, were employed in this investigation. Additionally, high-resolution mass spectrometry (Q-Orbitrap HRMS) was utilized for a comprehensive analysis of their polyphenolic constituents. Predominantly, rutin and isorhamnetin-3-rutinoside were the most prevalent compounds detected in the samples (514.62 and 318.59 mg/kg, respectively). Following in vitro GiD, the extract encapsulated in AcR capsules exhibited enhanced bioaccessibility during both the duodenal (189.2 and 162.5 mg GAE/100 g, respectively) and colonic stages (477.4 and 344.7 mg GAE/100 g, respectively) when compared with the extract encapsulated in NAcR capsules. This suggests that gastric acidity adversely impacted the release of polyphenols from NAcR capsules. In conclusion, the aqueous zucchini flower extract emerges as a promising and readily accessible source of dietary polyphenols. Moreover, the utilization of AcR capsules presents a potential nutraceutical formulation strategy to improve polyphenol bioaccessibility, enhancing its applicability in promoting health and well-being.

Osteopontin enhances the probiotic viability of Bifidobacteria in pectin-based microencapsulation subjected to in vitro infant gastrointestinal digestion

Encapsulation is usually adapted to improve probiotic viability under adverse environmental conditions, and used to ensure adequate amount of probiotics reach the distal gastrointestinal tract and achieve probiotic action. In the present study, sub-species of Bifidobacterium were encapsulated with pectin or alginate by an emulsification/internal gelation method. Bovine milk osteopontin (OPN) was used as an excipient with potential to improve the protection of the probiotics during processing and/or gastrointestinal digestion. Here, we reported that the use of OPN significantly improved probiotic viability during freeze drying and simulated infant gastrointestinal digestion. The viability of Bifidobacterium bifidum R0071 and Bifidobacterium breve M-16V loaded in pectin-based freeze-dried microcapsules with 0.5% OPN addition remained at over 106 CFU g−1 after simulated infant digestion. In comparison, the microcapsules without OPN had a probiotic viability of only 103 CFU g−1. The protective effect of OPN was proven to be dose dependent. For example, the B. bifidum R0071 viability was 6.1 log CFU·g−1 after the gastrointestinal digestion for the pectin-based microencapsulation without OPN addition, while the value remained at 8.4 log CFU·g−1 when OPN concentration reached 5%. In this study, we also demonstrated that extracellular calcium ions could chelate with OPN molecules which could be attributed to preventing damage of the probiotic cell wall and the improved protective effective of microencapsulation. Overall, these results provide new insight into the use of OPN as a microencapsulation excipient to promote probiotic viability and its potential future application in functional foods such as infant formula with enhanced gut health.

Xanthan gum and pectin as beverage stabilizers reduce the digestive enzyme hydrolysis of antioxidant and antihypertensive peptides obtained from a brewery byproduct

An acidic beverage was formulated with xanthan gum (XG), pectin (P) and brewer spent grain (BSG) peptides with antioxidant and antihypertensive properties. The impact of hydrocolloids levels on peptide bioaccessibility was studied. Peptides were obtained from BSG using Purazyme and Flavourzyme enzymes. BSG peptides were fractionated by ultrafiltration (UF) and four fractions were obtained: F1 (>10 kDa), F2 (10–5 kDa), F3 (1–5 kDa), and F4 (<1 kDa). F3 showed the highest protein purity, ferulic acid content, proportion of amphipathic peptides, and bioactive properties (ABTS+ radical scavenging and ACE-I inhibitory activity). The identified peptides from F3 by tandem mass spectrometry were 138. In silico analysis showed that 26 identified peptides had ABTS+ inhibitory activity, while 59 ones presented good antihypertensive properties. The effect of XG and P levels on bioaccessibility of F3 peptides in the formulated beverages was studied by a central composite experimental design. It was observed that F3 peptides interacted with hydrocolloids by electrostatic forces at pH of formulated beverages. The addition of hydrocolloids to formulation modulated the release of the antioxidant peptides and protected the degradation of ACE-I inhibitory peptides from F3 during simulated gastrointestinal digestion. Finally, the level of hydrocolloids that produced intermediate viscosities in the formulated beverages improved the bioaccessibility of the F3 peptides.

Impact of food matrix components on the physicochemical properties, release properties and bioaccessibility of unencapsulated and encapsulated vitexin

SummaryMung bean seed coat extract (ME), rich in antioxidants such as vitexin and iso‐vitexin, was encapsulated in egg yolk phosphatidylcholine to enhance its bioaccessibility and expand its application in food products. This study investigated the effect of the food matrix on the physical properties, chemical properties and release properties of bioactive compounds during simulated gastrointestinal digestion and analysed the morphology and chemical interactions of the samples. The ME and mung bean seed coat extract‐loaded phytosome particles (PS) were incorporated with four types of food ingredients including whey protein isolate, rice flour, butter and mixed ingredients. The highest total phenolic content (TPC) and antioxidant activity measured using DPPH radical scavenging activity and ferric reducing antioxidant power (FRAP) were detected in ME incorporated with whey protein isolate. PS incorporated with butter gave the highest values of TPC, DPPH and FRAP. After simulated intestinal digestion, ME incorporated with whey protein isolate gave the highest TPC, while the highest DPPH and FRAP values were found in ME incorporated with rice flour. Higher values of TPC, DPPH and FRAP were observed when PS was incorporated with all types of food ingredients compared to PS alone. Results suggested that the addition of PS enhanced the bioaccessibility of food ingredients.

Modifying rheological properties of psyllium by gamma irradiation enables development of low glycaemic index food with a predicted gastrointestinal tolerance

Gel forming dietary fibre like psyllium (PS) is effective in slowing down rate of digestion as well as absorption of glucose thereby reducing the postprandial glucose level and hence is used to develop functional foods for diabetic patients. The fortification level is however limited which otherwise elicit unwanted rheological response and poor sensorial quality in final product. In the present study this limitation was overcome by improving the functionality of the fibre by gamma radiation processing of the polysaccharides. We assessed the changes in rheological properties of radiation processed PS (RPPS) at different doses which enabled us to optimise the irradiation dose and levels of fortification of the RPPS in wheat flour for preparation of Indian unleavened bread (chapati). We observed that PS processed at a dose of 25 kGy could be incorporated to a level as high as 14 % in wheat flour yielding a sensorially better product compared to unfortified wheat flour. Further, the most striking effect observed for RPPS fortified chapati was reduction in the release of glucose upon subjecting to simulated gastrointestinal digestion. Finally, clinical and in vitro fermentation studies also confirmed a low GI value and high gastrointestinal tolerance of RPPS fortified chapati.

Impact of In Vitro Digestion on the Digestibility, Amino Acid Release, and Antioxidant Activity of Amaranth (Amaranthus cruentus L.) and Cañihua (Chenopodium pallidicaule Aellen) Proteins in Caco-2 and HepG2 Cells.

This study evaluated the impact of in vitro gastrointestinal digestion on the digestibility, amino acid release, and antioxidant activity of proteins from amaranth (Amarantus cruentus L.) and cañihua (Chenopodium pallidicaule Aellen). Antioxidant activity was assessed using ORAC, ABTS, DPPH, and cellular antioxidant activity (CAA) assays in human intestinal Caco-2 and hepatic Hep-G2 cell lines. The results showed that amaranth had higher protein digestibility (79.19%) than cañihua (71.22%). In addition, intestinal digestion promoted the release of essential amino acids, such as leucine, lysine, and phenylalanine, in both protein concentrates. Concentrations of amaranth and cañihua proteins, ranging from 0.125 to 1.0 mg mL-1, were non-cytotoxic in both cell lines. At a concentration of 0.750 mg mL-1, simulated gastrointestinal digestion enhanced cellular antioxidant activity. Intestinal digest fractions containing peptides >5 kDa were the principal contributors to CAA in both cell lines. Notably, cañihua proteins exhibited high CAA, reaching values of 85.55% and 82.57% in Caco-2 and HepG2 cells, respectively, compared to amaranth proteins, which reached 84.68% in Caco-2 and 81.06% in HepG2 cells. In conclusion, both amaranth and cañihua proteins, after simulated gastrointestinal digestion, showcased high digestibility and released peptides and amino acids with potent antioxidant properties, underscoring their potential health benefits.

Sunflower seed-derived bioactive peptides show antioxidant and anti-inflammatory activity: From in silico simulation to the animal model

The evolving field of food technology is increasingly dedicated to developing functional foods. This study explored bioactive peptides from sunflower protein isolate (SPI), obtained from defatted flour, a by-product of the oil processing industry. SPI underwent simulated gastrointestinal digestion and the obtained peptide-enriched fraction (PEF) showed antioxidant properties in vivo, in zebrafish. Among the peptides present in PEF identified by mass spectrometry analysis, we selected those with antioxidant properties by in silico evaluation, considering their capability to interact with Keap1, key protein in the regulation of antioxidant response. The selected peptides were synthesized and evaluated in a cellular model. As a result, DVAMPVPK, VETGVIKPG, TTHTNPPPEAE, LTHPQHQQQGPSTG and PADVTPEEKPEV activated Keap1/Nrf2 pathway leading to Antioxidant Response Element-regulated enzymes upregulation. Since the crosstalk between Nrf2 and NF-κB is well known, the potential anti-inflammatory activity of the peptides was assessed and principally PADVTPEEKPEV showed good features both as antioxidant and anti-inflammatory molecule.

Comparative Study of Polyphenol Profile after Stimulated Post-intestinal Digestion of Raw and Dried Ginger Leaves

Abstract The present study aimed to determine bioaccessibility (BA) of polyphenols (PPs) and flavonoids (FLs) compounds of Ginger (Zingiber officinale) leaves extract after simulated gastrointestinal digestion (GID). One hundred grams of Z. officinale leaves (raw and dried) was extracted with 200 mL of distilled water. Determination of PPs and BA index were carried on the extract before digestion (BD) (undigested), post-intestinal digestion without enzymes (PI-DWOEs) and post-intestinal digestion with enzymes (PI-DWEs) using standard methods. The results showed significant decrease in proanthocyanidins (PCs) and anthocyanins (ACs) of dried and raw Z. officinale in PI-DWEs when compared to PCs and ACs level in BD. A total of nine major PPs compounds were detected in raw Z. officinale leaves in BD and PI-DWOEs, whereas eight PPs were detected in PI-DWEs. In PI-DWOEs, sinapinic acid (6.68 ng/mL) was the most prominent whereas p-coumaric (7.74 ng/mL) was the most protuberant in PI-DWEs. The concentration of total PPs were as follows; BD (41.39 ng/mL) &gt; PI-DWEs (13.6 ng/mL) &gt; PI-DWOEs (19.20 ng/mL). In conclusion, after the in vitro GID of the extract, a good BA index was observed, of which some PPs and FLs contents were near to 100%. However, the reason most PPs and FLs in the extract cannot be available or absorbed intact after digestion could be due to the fact that they undergo a series of reactions with intestinal enzymes. Additionally, not all polyphenols are absorbed equally well. Before it is feasible to predict how PPs will be assimilated by cells, they must first be bioaccessible.

Curcumin-loaded oil body emulsions prepared by an ultrasonic and pH-driven method: Fundamental properties, stability, and digestion characteristics

In this study, oil bodies (OBs) loaded with curcumin (Cur) were successfully prepared via an ultrasonic and pH-driven method. Ultrasonic treatment significantly improved the encapsulation efficiency (EE) and loading capacity (LC) of Cur, producing OB particles with small size, uniform distribution, and high ζ-potential absolute values. When the ultrasonic power was 200 W, the EE, LC, and ζ-potential absolute value were the greatest (88.27 %, 0.044 %, and −25.71 mV, respectively), and the OBs possessed the highest yellowness, representing the best treatment result. The confocal laser scanning microscopy (CLSM) and cryo-scanning electron microscopy (cryo-SEM) results was also intuitionally shown that. Moreover, circular dichroism (CD) proved that ultrasonic treatment could unfold the surface protein structure, further enhancing the stability. Therefore, the cream index (CI), peroxide value (POV), and thiobarbituric acid reactive substances (TBARS) were the lowest when the ultrasonic power was 200 W. In this case, the Cur loaded in OBs was well protected against hostile conditions, evidenced by the highest Cur retention rate and the lowest degradation rate constant. Finally, the in vitro gastrointestinal digestion simulation results showed that the ultrasonic treatment effectively increased the release of FFA, bioaccessibility, and stability of Cur, especially when the ultrasonic power was 200 W. This research offers a new OB-based delivery system to stabilize, deliver, and protect Cur for food processing.

Characterization and stability of soybean meal peptide-zinc chelate prepared by solid state fermentation with Aspergillus oryzae

This study aimed to prepare soybean meal peptide (SBMP)-Zn(II) chelate using solid state fermentation (SSF) with Aspergillus oryzae and characterize its structural properties. The SBMP showed good ability to chelate Zn(II). The Fraction 2–1 with the maximum chelating activity up to 365.75 mg/g was obtained from SBMP by chromatography. The identified 27 peptide segments in SBMP with 570–1500 Da (5–10 amino acids) mainly could combine with Zn(II) via the amino, carboxyl, hydroxyl and imidazole group to form peptide-Zn(II) chelates. The SBMP-Zn(II) chelate was stable in thermal processing, which was higher than SBMP due to the formation of eutectic structure in chelate. SEM analysis showed the formation of large polymer particles due to the crosslinking of Zn(II). The acid, thermal and high salt environment were the major factors affecting SBMP-Zn(II) dissociation. The chelate could effectively promote Zn(II) absorption in vitro simulated gastrointestinal digestion. These findings would provide the theoretical basis and technical support for the low-cost, efficient, and large production of the chelate and high-value resource utilization of SBM.

Microfluidic fabrication of encapsulated probiotic microspheres using cysteine-modified chitosan with dual functions of bacterial adhesion and intestinal mucosal adhesion

Compared with previous encapsulation methods, the emerging microfluidic approach has the potential of preparing monodispersed particles with considerable advantages, such as controlled size and morphology, stable yield, and enhanced repeatability. In addition to introducing probiotics to the intestine with high-viability, designing a novel carrier matrix to improve the mucoadhesion of probiotics in the intestine is imperative. Thus, in this study, the thiol groups of cysteine were grafted to chitosan to form disulfide bonds with the cysteine residues on the bacterial surface and mucus to achieve the dual function of probiotic adhesion and mucoadhesion. Upon examination, the adhesion rate of Bifidobacterium bifidum FL-276.1 (FL-276.1) to thiolated chitosan film increased by 1.33 times compared with non-modified chitosan film. Thiolated chitosan microspheres prepared by microfluidic method assisted by a crosslinking unit with a crosslinker of genipin had a uniform size distribution, high loading efficiency (80%) to FL-276.1, and improved resistance to simulated gastrointestinal digestion with a survival rate of FL-276.1 up to 92%. Moreover, the results of mucoadhesion test of thiolated chitosan microspheres demonstrated that the amount of thiolated chitosan microspheres adhered to the HT-29 cells was 2.27 times higher than that of chitosan microspheres. The monodispersed cysteine modified chitosan microspheres with dual adhesion function prepared by microfluidic technology has the potential to enhance the viability and function of probiotics after gastrointestinal digestion and intestinal adhesion.

Effect and Mechanism of Soluble Starch on Bovine Serum Albumin Cold-Set Gel Induced by Microbial Transglutaminase: A Significantly Improved Carrier for Active Substances.

Soluble starch (SS) could significantly accelerate the process of bovine serum albumin (BSA) cold-set gelation by glucono-δ-lactone (GDL) and microbial transglutaminase (MTGase) coupling inducers, and enhance the mechanical properties. Hardness, WHC, loss modulus (G″) and storage modulus (G') of the gel increased significantly, along with the addition of SS, and gelation time was also shortened from 41 min (SS free) to 9 min (containing 4.0% SS); the microstructure also became more and more dense. The results from FTIR, fluorescence quenching and circular dichroism (CD) suggested that SS could bind to BSA to form their composites, and the hydrogen bond was probably the dominant force. Moreover, the ability of SS to bind the original free water in BSA gel was relatively strong, thereby indirectly increasing the concentration of BSA and improving the texture properties of the gel. The acceleration of gelling could also be attributed to the fact that SS reduced the negative charge of BSA aggregates and further promoted the rapid formation of the gel. The embedding efficiency (EE) of quercetin in BSA-SS cold-set gel increased from 68.3% (SS free) to 87.45% (containing 4.0% SS), and a controlled-released effect was detected by simulated gastrointestinal digestion tests. The work could put forward new insights into protein gelation accelerated by polysaccharide, and provide a candidate for the structural design of new products in the food and pharmaceutical fields.

Effect of ficin-hydrolyzed wheat gluten on bread quality and invitro antioxidant activity before and after simulated gastrointestinal digestion.

This study aimed to investigate the effect of adding ficin-hydrolyzed wheat gluten at different levels (0%, 1%, 2%, 4%) on bread quality, and invitro antioxidant activity before and after simulated gastrointestinal digestion. Our findings revealed that the incorporation of the generated wheat gluten hydrolysates (WGH) up to 4 g per 100 g flour positively affected the technological and physical-chemical characterizations of breads, including dough rheological properties, color, specific volume, and moisture. The texture profile analysis indicated reductions in hardness, springiness, and chewiness of the breads, and confirmed anti-staling properties during storage. The enriched breads received satisfactory scores from the sensory panel and were perceived as less stale after a 4-day period of storage. The aroma score of the 4% WGH bread was significantly higher than other treatments. Regarding taste, the 4% WGH bread scored the lowest, but the obtained value was not statistically significant. The enriched breads exhibited DPPH, ABTS radical scavenging, and Fe2+ chelation abilities that increased in response to higher levels of hydrolysate incorporation, and these antioxidant activities were enhanced after simulated gastrointestinal digestion. Our findings confirm that it is possible to apply ficin-generated WGH to enhance physicochemical, nutritional, and biological quality of bread.

Formation of adducts during digestion triggered dietary protein for alleviating cytotoxicity of 2-tert-butyl-1,4-benzoquinone

2-tert-butyl-1,4-benzoquinone (TBBQ), a degradation product of lipid antioxidant Tert-Butylhydroquinone (TBHQ), is a new hazardous compound in foods. This study investigated whether co-ingestion of dietary protein and TBBQ can alleviate the toxicity of TBBQ. The results indicated that soy protein isolate, whey protein isolate, and rice protein significantly reduced the residual amount of TBBQ during simulated gastrointestinal digestion. This result was attributed to the excellent elimination capacity of the released amino acids for TBBQ through formation of adducts. Among 20 amino acids, histidine, lysine, glycine, and cysteine showed better elimination capacity for TBBQ; they can eliminate 92.1%, 89.4%, 86.1%, and almost 100%, respectively, in 5 min at pH 8.0. Further study indicated that amino acids with lower ionization constant exhibited greater TBBQ elimination capacity. In addition, incubation of the cells with 50 μM TBBQ for 12 h decreased the cell viability to 28.95 ± 3.25%; while amino acids intervention was involved in the alleviation of TBBQ cytotoxicity via decreasing ROS. Particularly, cysteine showed 100 times more TBBQ detoxifying capacity than other amino acids. This work could provide a theoretical basis for the potential application of amino acids for detoxifying TBBQ in the food industry.

Edible bubbles: A delivery system for enhanced bioaccessibility of phenolic compounds in red fruits and edible flowers

In this study, we developed edible bubbles as a delivery system for enhancing the bioaccessibility of phenolic compounds in red fruits and edible flowers. The bubbles were formed using a spherification method and characterized for their physical properties. The diameter of the bubbles ranged from 8.14 mm to 9.83 mm, and the mass varied from 0.346 g to 0.428 g, which was suitable for consumption with bubble teas. Compared to existing products, the spherification manufacturing method differentiated these bubbles. The addition of phenolic extracts influenced the internal structure of the bubbles, as observed through changes in roughness and elemental composition. Energy dispersive spectroscopy analysis confirmed the presence of carbon, oxygen, sodium, chlorine, and calcium in the bubbles. Silicon was detected in samples containing extracts. Atomic force microscopy images showed variations in roughness, suggesting an interaction between the internal wall and bioactive compounds. Edible bubbles exhibited a total phenolic compound concentration of up to 182 μg GAE/g, while antioxidant activity reached as high as 9748.54 μg TE/g as determined by the DPPH assay. Simulated gastrointestinal digestion demonstrated higher bioaccessibility and remaining antioxidant activity in the edible bubbles compared to isolated extracts. Chromatographic analysis revealed the presence of individual phenolic compounds before and after digestion, indicating the release of adsorbed compounds during in vitro gastrointestinal digestion of edible bubbles. In conclusion, these edible bubbles offer a novel delivery system for enhancing the bioaccessibility of phenolic compounds. Their unique physical and chemical properties and the spherification method make them promise for use in the functional food and beverage industries. Further research is needed to explore sensory attributes and product stability.

Simulated in vitro gastrointestinal digestion of β-lactoglobulin treated by ultrasound: Detection of peptides profile and the antioxidant activity

The influence of ultrasonic pretreatment on the release and antioxidant activity of potential antioxidant peptides after in-vitro simulated gastrointestinal digestion of β-lactoglobulin (BLG) were measured by HPLC-MS/MS, chemical and cellular-based assays. The gastrointestinal digest was fractionated into four fractions by Sephadex G-25 gel filtration column, and fractions showed a considerable ABTS·+ scavenging ability. The fraction with the strongest antioxidant activity was produced by ultrasonicated BLG after gastrointestinal digestion, which relies on ultrasonic-promoted proteolysis to produce many small-molecule antioxidant peptides. The best active fraction has better cellular antioxidant activity and protection of H2O2-induced oxidative HepG2 cell model, which significantly increases the activities of antioxidant enzyme, and is concentration-dependent. HPLC-MS/MS analysis showed that there were more potential antioxidant peptides in the best active fraction. This research will provide a basis for the further application of ultrasonic in dairy products, which can promote the release of more potential antioxidant peptides-derived from gastrointestinal digestion.

Thermo-kinetic studies of in vitro digestion and colonic fermentation of inulin/Lactobacillus rhamnosus GG co-encapsulated composite beads

In this study, Lactobacillus rhamnosus GG (L.GG) and inulin were successfully co-encapsulated into alginate/pectin composite beads using high efficiency vibration technology with freeze-drying. The addition of inulin did not substantially affect the morphology or particle size of microcapsules but improved the survival number of L.GG during encapsulation process, storage and in vitro digestion. Isothermal microcalorimetry was used for the first time to investigate the thermo-kinetics properties of these encapsulated L.GG during in vitro gastrointestinal digestion and colon fermentation, revealing that the co-encapsulation with inulin increased the growth rate of L.GG in the logarithmic growth phase, without change the total heat production. The number of probiotic microcapsules surviving after 60 days of storage was still more than 8 Log CFU/g. Inulin co-encapsulation also significantly improved the storage and heat stability of L.GG, with the highest viability of 8 Log CFU/g after 60-day storage, 5.58 Log CFU/g after heating at 63 °C for 30 min, and 7.85 Log CFU/g at 72 °C for 3 min, respectively. These microcapsules also altered the composition and diversity of mice gut microbiota, increasing the relative abundance of Lactobacillus and decreasing that of Bacteroides. This study introduces a novel colon-targeted probiotic-delivery system and a method to understand the control-release thermodynamics of the encapsulated probiotics in simulated gastrointestinal digestion and colonic fermentation.

Discovery and Characterization of a Dual-Function Peptide Derived from Bitter Gourd Seed Protein Using Two Orthogonal Bioassay-Guided Fractionations Coupled with In Silico Analysis.

The hydrolysate of bitter gourd seed protein, digested by the combined gastrointestinal proteases (BGSP-GPs), exhibited the most potent inhibition on angiotensin-I-converting enzyme (ACE) with an IC50 value of 48.1 ± 2.0 µg/mL. Using two independent bioassay-guided fractionations, fraction F5 from reversed-phase chromatography and fraction S1 from strong cation exchange chromatography exhibited the highest ACE inhibitory (ACEI) activity. Three identical peptides were simultaneously detected from both fractions and, based on the in silico appraisal, APLVSW (AW6) was predicted as a promising ACEI peptide. Their dipeptidyl peptidase-IV (DPP4) inhibitory (DPP4I) activity was also explored. The IC50 values of AW6 against ACE and DPP4 were calculated to be 9.6 ± 0.3 and 145.4 ± 4.4 µM, respectively. The inhibitory kinetics and intermolecular interaction studies suggested that AW6 is an ACE competitive inhibitor and a DPP4 non-competitive inhibitor. The quantities of AW6 in BGSP-GP hydrolysate, fractions F5 and S1, were also analyzed using liquid chromatography-tandem mass spectrometry. Notably, AW6 could resist hydrolysis in the human gastrointestinal tract according to the result of the simulated gastrointestinal digestion. To the best of our knowledge, this is the first discovery and characterization of a dual-function (ACEI and DPP4I activities) peptide derived from bitter gourd seed protein.

Determination of the Viability of Lactic Acid Bacteria by Dynamic In Vitro Gastrointestinal Model in Household and Industrial-Type Kefir Samples.

This study presents results based on differences in the antioxidant activity and lactic acid bacteria counts in different parts of the digestive tract following simulated gastrointestinal digestion of kefir samples. Statistically significant differences were observed in Lactobacillus counts in different kefir types including industrial (IK), starter culture (SCK), and kefir grains (KG). These differences were observed between the initial and second min in the mouth region (T = 3.968; p < 0.05); and between the initial, 60th, and 120th min in the stomach region (R = 11.146; p < 0.05). Additionally, a statistically significant difference was noted in the initial Lactobacillus levels among the IK, SCK, and KG in the stomach region (H = 7.205; p < 0.05). Also, significant differences were identified between the Lactococcus counts of IK across 0, 60, and 120 min in the stomach region (R = 10.236; p < 0.05). Notably, a statistically significant difference was noted in the Lactococcus levels in the KG between the initial and second min in the mouth region (T = 3.101; p < 0.05) and between 0, 60, and 120 min in the stomach region (R = 25.771; p < 0.001). These findings highlight the differences between the physicochemical characteristics of different kefir types. A decrease in lactic acid bacteria counts in kefir samples was observed throughout the dynamic in vitro gastrointestinal tract to reveal the significance of the digestive process when determining probiotic product capacity.