Digestive Stability Research Articles

Ultrasound-enzyme-assisted extraction of flavonoids, polysaccharides, and triterpenes from Gualou and Xiebai: optimization, bioactivity, in vitro digestive stability, and impact on lipid digestion.

Gualou (Trichosanthes kirilowii Maxim) and Xiebai (Allium macrostemon Bunge) have been extensively studied for their diverse active ingredients, which include flavonoids, polysaccharides, and triterpenoids. This study employed a single-factor experiment alongside the Plackett-Burman design and utilized response surface methodology to optimize the ultrasonic-enzyme-assisted extraction (U-EAT) method for the functional components in Gualou and Xiebai (GLXB). The optimal extraction conditionswere identifiedas a solid-to-liquid ratio of 1:11g/mL, an alcohol concentration of 55%, an enzyme concentration of 1.2%, and an extraction temperature of 40°C. The yields of flavonoids, polysaccharides, and triterpenoids obtained were 0.94±0.05, 260.46±1.78, and 118.69±0.71mg/g, respectively, demonstrating increases of 59.19%, 29.03%, and 46.10% compared to HL (HL, the traditional reflux extraction method). Furthermore, in vitro digestion of the GLXB extract demonstrated significant lipid-lowering and hypoglycemic effects. The GLXB extract facilitated the flocculation of lipid droplets during lipid digestion and exhibited the capacity to reduce the rate of fat digestion. These findings indicate that the U-EAT significantly enhanced the content of active ingredients in GLXB and improved the hypoglycemic and lipid-lowering activities of the GLXB extract, highlighting its potential for further development and application in functional foods.

Gum arabic-stabilized emulsion systems: Underlying mechanisms for enhancing storage and digestion stability of curcumin.

Although the benefits of gum arabic (GA) in developing emulsion systems are well known, the mechanism underlying its stability-enhancing effect of GA in emulsion systems stabilized with curcumin remains unclear. This study used GA-stabilized emulsion system, containing 10wt% medium-chain triglycerides and 0.1% curcumin. Results demonstrated that when the GA concentration exceeded 0.5wt%, the interface layer reached saturation, maintaining a consistent thickness of approximately 34.8nm. The curcumin-containing emulsion demonstrated good stability during storage at room temperature and heating treatment, effectively protecting the curcumin. However, during in vitro intestinal digestion, the formation of salt and protein bridges caused the aggregation of oil droplets, resulting in an increase in the droplet size to 975.2nm, while the curcumin content remained stable. Additionally, the in vitro release rate of encapsulated curcumin (44.0%) was significantly higher than that of free curcumin (19.5%). In conclusion, this study elucidated the stability-enhancing mechanism of GA-stabilized emulsions for curcumin and highlighted the potential of GA in developing emulsion systems for the encapsulation of these compounds.

Preparation and evaluation of novel Agriophyllum squarrosum starch nanoparticles for encapsulation of lycopene with enhanced retention rate and bioactivity during simulated in-vitro digestion.

In this study, we developed novel Agriophyllum squarrosum starch nanoparticles (ASSNPs) for the encapsulation of lycopene (LYC), aiming to enhance its stability and bioactivity under adverse environmental and digestive conditions. The small-granule starch extracted from A. squarrosum seeds was processed using ionic liquids (ILs) as an effective "green" solvent, followed by a systematic treatment involving ultrasonication and pullulanase to prepare the ASSNPs. The resulting nanoparticles exhibited small size, narrow particle size distribution, negative zeta potential, and high encapsulation efficiency of up to 64.3 %. The structures of ASSNPs were characterized using Fourier transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, scanning electron microscopy, and transmission electron microscopy. These analytical techniques confirmed the successful encapsulation of LYC and revealed increased intermolecular interactions. Stability and degradation experiments demonstrated that the retention of the LYC in the complexes was significantly higher than that of the unencapsulated LYC, highlighting the superior protective effects of ASSNPs on the storage and digestive stability of LYC. This research elucidated the structural features of the complex between ASSNPs and LYC, underscoring the potential of ASSNPs as a food-grade delivery system. This approach offers a sustainable method for enhancing the bioavailability of hydrophobic nutraceuticals.

Rapid screening and identification of novel dipeptidyl peptidase IV inhibitory peptides from buffalo milk.

Peptidomics combined with molecular docking is an effective alternative method for rapid screening of novel bioactive peptides in food. Buffalo milk as a potential source of dipeptidyl peptidase-IV (DPP-IV) inhibitory peptides has been less studied. Peptidomics and molecular docking methods were employed to rapidly screen new DPP-IV inhibitory peptides from buffalo milk. The screened DPP-IV inhibitory peptides were further verified using an in vitro inhibition assay and a Caco-2 cell assay. The DPP-IV inhibition rate of buffalo milk was increased from 73.40 ± 6.01% to 97.23 ± 3.18% in an in vitro digestion assay, suggesting that buffalo milk could be a promising source of DPP-IV inhibitory peptides. Subsequently, two novel peptides (GPFPIIV and FPQYL) with potential DPP-IV inhibitory activity were screened using peptidomics, molecular docking and an in vitro inhibitory assay. The IC50 values for GPFPIIV and FPQYL were 0.2998 ± 0.03 and 0.1407 ± 0.01 mg mL-1, respectively. During simulated gastrointestinal digestion in vitro, FPQYL had an excellent digestive stability of 92.13 ± 1.03%, whereas that of GPFPIIV was 59.52 ± 2.56%. In addition, GPFPIIV and FPQYL (1.00 mg mL-1) showed significant DPP-IV inhibitory effects in a Caco-2 cell assay, with the inhibition rate increasing to 32% and 36%, respectively. In summary, two new DPP-IV inhibitory peptides were screened from buffalo milk through a combination of peptidomics and molecular docking, both of which exhibited significant DPP-IV inhibitory activities. The identified peptides, GPFPIIV and FPQYL, have promising applications in diabetes management. © 2025 Society of Chemical Industry.

Fabrication of Rubus chingii Hu ellagitannins-loaded W/O and O/W emulsion gels: Structure, stability, in vitro digestion and in vivo metabolism.

Tannin is the main naturally occurring phytochemicals in Rubus chingii Hu with poor digestive stability and low bioavailability. In this study, oil-in-water (O/W) and water-in-oil (W/O) emulsion gels encapsulating Rubus chingii Hu ellagitannins (RCHT) were fabricated and their structure, rheology, stability, in vitro digestion and in vivo metabolism were characterized. The W/O emulsion gel showed smaller particle size, better pH stability, thermal stability, centrifugal stability and storage stability. Regarding rheology, two emulsion gels exhibited characteristics of non-Newtonian fluids. The encapsulation efficiency of W/O emulsion gel was higher, reaching 95.46%. The lower release rate and higher bioaccessibility of RCHT were also observed in the W/O emulsion gel. In vitro fermentation results indicated that W/O emulsion gel could promote the growth of intestinal beneficial bacteria and inhibit the growth of harmful bacteria. Metabolic kinetics in rats showed that the embedding of W/O emulsion gel greatly promoted the absorption and transformation of ellagitannins to urolithins in vivo. Thus, the W/O emulsion gel was quite suitable for the delivery of RCHT.

Bioaccessibility of Flavones, Flavanones, and Flavonols from Vegetable Foods and Beverages.

The bioaccessibility of flavonoids is of paramount importance in determining their bioavailability and biological effects. Bioaccessibility is influenced by several aspects, comprising the food matrix and the structure of flavonoids. In the present study, the bioaccessibility of different classes of flavonoids (flavanones, flavones, and flavonols) was investigated after in vitro gastro-intestinal digestion of beverages and vegetables. O-glycosylated flavanones were stable during in vitro digestion and easily released from the food matrix. Otherwise, C-glycosylated flavanones displayed a lower bioaccessibility index. Similarly, flavones exhibited a high bioaccessibility index in beverages and vegetables, with the O-glycosylated forms being more stable than the C-glycosylated. Flavonols displayed different stability under gastro-intestinal conditions depending on their structure. The presence of a catechol moiety in the B-ring, as observed in 3-O-glycosylated quercetins, negatively impacted flavonol stability in comparison with kaempferol derivatives that lack the catechol moiety. Indeed, the presence of more than one sugar or the glycosylation of the OH group in the B-ring improved the digestive stability of quercetin derivatives. For flavonols, a clear food matrix effect was observed by comparing the bioaccessibility in beverages and vegetable foods. These findings may aid in improving the comprehension of the biological effects of flavonoids and flavonoid-rich foods.

Relevance of Anthocyanin Metabolites Generated During Digestion on Bioactivity Attributed to Intact Anthocyanins.

Epidemiological and in vitro studies suggest that dietary anthocyanins in their intact form exert beneficial effects on human health. However, the potential contributions of anthocyanin metabolites to these beneficial effects have been underestimated. The objective of this review was to critically analyze the outcomes of studies concerning the formation, identification, cellular transport, and biological actions of anthocyanin metabolites generated during digestion to formulate several premises supporting the idea that these compounds largely contribute to human health. Studies performed using purified or semi-purified anthocyanins under digestion or physiological conditions were prioritized in this review. It was found that the information available about the digestive stability and metabolism of anthocyanins, as well as about their transport and deposition in human tissues has mostly been generated using plant extracts or tissues naturally containing compounds identified as anthocyanin metabolites or compounds that can serve as precursors of compounds identified as anthocyanin metabolites. This has significantly compromised the accurate identification of anthocyanin metabolites. Studies with pure or semi-purified anthocyanins are scarce in this regard. Some analytical procedures have also led to the unreliable identification and quantification of anthocyanin metabolites and, consequently, to the unreliable determination of their contribution to human health. Evidence suggests that anthocyanins are also highly metabolized in the gastrointestinal tract and transported, stored, and biologically active as their intermediary structures and final metabolites.

Preparation, characterization, stability, and antioxidant of quercetin-loaded hyaluronic acid complexes via pH-induced co-assembly

The purpose of this study was to investigate the feasibility of constructing an oral delivery system for quercetin (QUT) using hyaluronic acid (HA) as the wall material. The findings revealed that when the mass ratio of QUT to HA was 1:10, the prepared QUT-HA complexes exhibited excellent stability (particle size of 802 nm, zeta potential of -36 mV) and QUT loading capacity (encapsulation efficiency of 79.77%, loading capacity of 89.65 mg/g). The characterization of QUT-HA complex confirmed the formation of hydrogen bond between QUT and HA, resulting in a homogeneously dispersed coral-like complex and leading to the transformation of QUT's crystal structure into an amorphous state. Environmental stability analysis demonstrated that the QUT-HA complex maintains good stability within an ionic concentration range of 0-500 mM, a pH range of 3-8, and at temperatures of 50-90°C. In vitro simulations of gastrointestinal digestion indicated that the QUT-HA complex aggregates during simulated gastric fluid digestion and dissociates following simulated intestinal fluid digestion, effectively enhancing the bioaccessibility of QUT. Antioxidant assays showed that the scavenging ability of QUT against DPPH and ABTS radicals was significantly improved by complex loading. Therefore, the QUT-HA complex developed in this study possesses a high QUT loading capacity, excellent processing and digestive stability, and can effectively enhance the bioaccessibility and antioxidant activity of QUT, making it a promising candidate for use as an oral nutritional supplement in the field of functional foods.

Machine Learning for Enhancing Prediction of Biogas Production and Building a VFA/ALK Soft Sensor in Full-Scale Dry Anaerobic Digestion of Kitchen Food Waste

Based on operational data collected over 1.5 years from four industrial-scale dry anaerobic digesters used for kitchen food waste treatment, this study adopted eight typical machine learning algorithms to distinguish the best methane prediction model and to develop a soft sensor based on the VFA/ALK ratio. Among all the eight tested models, the CatBoost (CB) algorithm demonstrated superior performance in terms of prediction accuracy and model fitting. Specifically, the CB model achieved a biogas production prediction accuracy (R2) ranging from 0.604 to 0.915, and a VFA/ALK R2 between 0.618 and 0.768 on the test dataset. Furthermore, the feature importance analysis revealed that biomass amount into the dry anaerobic digester was the primary factor influencing biogas production. Chemical oxygen demand (COD) and total ammonia nitrogen (TAN) were identified as the most significant factors impacting the VFA/ALK indicator during dry anaerobic digestion, collectively contributing to nearly 50% of the influence. Overall, this study verifies the feasibility of using machine learning to predict biogas production in industrial-scale dry anaerobic digestion and provides a crucial foundation for monitoring the stability of dry anaerobic digesters.

Microbial transitions and degradation pathways driven by butyrate concentration in mesophilic and thermophilic anaerobic digestion under low hydrogen partial pressure.

Butyrate accumulation significantly affects the efficiency and stability of anaerobic digestion, while its specific impact on methane yield and butyrate degradation remains unclear. This study investigated how butyrate concentrations (2.0, 5.0, 10.0, and 20.0 g COD/L) affected methane production and butyrate degradation at 37 °C and 55 °C. Methane yield decreased when butyrate concentrations exceeded 10.0 g COD/L. Methanogenesis transitioned from the acetoclastic to the hydrogenotrophic pathway with butyrate concentration increasing at 37 °C, but this transition wasn't observed at 55 °C. Butyrate was fully degraded at butyrate concentrations of 2.0-20.0 g COD/L. Iso-butyrate production was observed at 37 °C, while it only occurred with 20 g COD/L butyrate at 55 °C. Metagenomic analysis identified distinct microbes responsible for butyrate degradation at each temperature, and revealed a novel iso-butyrate metabolic pathway. These insights significantly advance the comprehension of microbial and enzymatic mechanisms driving butyrate degradation and methane production.

Oxygen influences in vitro assessment for phenolic compounds: Digestive stability, α-glucosidase inhibitory activity and bioavailability

Phenolic compounds are popular in screening novel hypoglycemic agents, but the impact of oxidative degradation on the determination of α-glucosidase inhibitory activity and bioavailability is unclear. Here we showed 12 phenolic compounds structure-dependently degraded during standard simulated digestion, while in physiological hypoxia their retention rates were all over 87.89 %. This enhancement of digestive stability resulted in the biggest drop of 31.72 % in IC50 against α-glucosidase and a significant increase in bioavailability. Enzyme kinetic and multi-spectroscopic analysis confirmed oxygen weakened the affinity of compounds to α-glucosidase, but the mechanisms were not changed. Moreover, a two-chamber culture system was designed to meet conflicting demands for oxygen between epithelium and cavity, and better α-glucosidase inhibitory activities (51.61 % maximum reduction in glucose production) and absorption rates (up to 1.10 % from undetectable) were obtained than those of uncontrolled oxygen. Hence, the oxygen level should be monitored to assess the activities of phenolic compounds in vitro.

Fe/Co-modified Enteromorpha bio-hydrochar enhanced anaerobic digestion of chicken manure with sulfadimethazine: focusing on synergistic mechanism and microbial community succession

Residual antibiotics in chicken manure may interfere with the stability of anaerobic digestion (AD) and inhibit resource utilization efficiency. In this study, we aimed to enhance chicken manure bio-methanation in AD with high-concentration of sulfamethazine (SMZ) by adding metal (Fe, Co)-modified Enteromorpha-based hydrochar (Co-HC, Fe-HC). The results showed that Fe-HC and Co-HC increased the degree of acidogenesis by 1.25 times and 1.58 times, respectively. The maximum protein concentration in EPS was increased by 47.64% and 72.5% after adding Fe-HC and Co-HC. However, only Co-HC demonstrated notable improvements in both methane production and SMZ removal efficiency. Electrochemical analysis showed that Co-HC possessed a richer variety of oxygen and nitrogen functional groups, along with superior electron exchange capabilities compared to Fe-HC. Furthermore, microbiological assessments revealed that Co-HC enriched syntrophic bacteria (such as Syntrophomonas and Mesotoga), facilitating direct interspecies electron transfer (DIET) and subsequently enhancing biomethane production. The abundance of genes involved in electron transfer increased significantly with Co-HC, with a maximum increase of 75.86% in Co1.5-HC treatment. Additionally, the elimination of antibiotic resistance genes (sul1, sul2) increased by 65.66% in the Co1.5-HC treatment. This study offers a theoretical foundation and empirical support for the synergistic improvement of livestock and poultry manure containing high antibiotic concentrations, thereby helping to overcome challenges posed by recalcitrant substances.Graphical

Investigating the non-covalent interactions between rutin and superoxide dismutase: Focus on thermal stability, structure, and in vitro digestion

Rutin is prone to degradation during processing, highlighting the need for a suitable protein system for its delivery. This study evaluated the effects of pH and concentration ratios on the interaction between rutin and superoxide dismutase (SOD), aiming to develop a suitable non-covalent delivery system. The highest thermal stability was observed at pH 4 with a rutin-to-SOD concentration ratio of 5:1, where the melting temperature (Tm) reached 67.8 °C, and the half-life was 176 min. Infrared spectroscopy and particle size analysis revealed that rutin has minimal impact on the secondary structure of SOD; however, high concentrations of rutin influence the quaternary structure of SOD, leading to aggregation. Molecular docking and molecular dynamics simulations further confirmed that the interaction between rutin and SOD occurs through hydrogen bonding and hydrophobic interactions, with pH altering their binding sites. At pH 5 and pH 6, the digestive stability of the SOD-rutin complex was the highest. This study provides a theoretical basis for the preparation of highly stable SOD-rutin complexes and identifies a new protein system for the stabilization of rutin.

Alteration in rheological and digestive properties of O/W emulsions using controlled aggregation of konjac glucomannan and xanthan gum in aqueous phases

The modulation of lipid digestion and emulsion stability remains a pivotal area of research, crucial for developing healthier food products with enhanced sensory and nutritional attributes. This study investigates the influence of konjac glucomannan (KGM) and xanthan gum (XG) on oil-in-water (O/W) emulsions throughout simulated gastrointestinal tract (GIT) digestion, focusing on rheological properties, microstructure evolution, and lipid release kinetics. Three distinct O/W emulsions were formulated with 20 wt% oil content, incorporating either 0.8 wt% XG, a 1:1 mixture of KGM and XG (KGM/XG), or a blend of KGM-XG. Rheological assessments revealed all emulsions exhibited shear-thinning behavior across applied shear rates (0.1–100 1/s). During gastric and small intestinal digestion phases, the KGM-XG emulsion exhibited significantly higher viscosity at higher shear rates (2.512–100 1/s), indicating robust molecular interactions between KGM and XG under digestive conditions. The analysis of microstructure, particle size, and flow behavior showed that the KGM-XG emulsion exhibited significantly (p < 0.05) higher viscosity and smaller particle sizes compared to other systems throughout the digestion process. This finding indicates that KGM-XG emulsion demonstrates a strong resistance to enzymes and digestive fluid during the transition from oral to small intestinal phases. Importantly, the extent of free fatty acid (FFA) release at the end of the small intestinal phase was highest for XG (34.4%), followed by KGM/XG (15.65%) and KGM-XG (13.23%). These findings highlight the potential of KGM-XG emulsions to modulate lipid digestion kinetics, offering applications in designing emulsion-based foods, such as sauces, beverages, and reduced-fat foods.

Construction of glycosylated zein-based colloids to simultaneously improve fucoxanthin’s thermal processing adaptability, digestive stability, and oral bioavailability

Fucoxanthin (FX) is a carotenoid found in marine environments with a range of nutritional functions. However, its application in the food industry has been restricted by its vulnerability to deterioration and absorption challenges. This study employed zein to develop hydrophilic colloids to enhance the thermal processing adaptability, gastrointestinal digestive stability, and oral bioavailability of FX. The findings demonstrated that the using glucose for the grafting modification of zein caused a deviation in its isoelectric point, reduced its water contact angle, and altered its secondary structure, resulting in higher hydrophilicity. Using glycosylated zein (GZ) for FX loading yielded homogenous, stable aqueous GZ-FX complex dispersion solutions with an encapsulation efficiency (EE) > 85.00 %, a particle size < 210.00 nm, a zeta-potential > −30.00 mV, and a polydispersity index (PDI) < 0.30. GZ-based encapsulation notably enhanced the thermal stability of FX, retaining approximately 90.00 % and 80.00 % of the FX at 65 ℃ and 100 ℃, respectively. During in vitro simulated gastrointestinal digestion, GZ-encapsulation of FX demonstrated a retention increase of 30.63 % and a 2.31-fold higher micellization rate. The in vivo absorption results showed that GZ-based encapsulation dramatically increased FX oral bioavailability, while its serum, liver, and kidney response levels were 51.49-fold, 5.13-fold and 6.73-fold higher. This study suggests that glycosylated alcohol-soluble proteins are highly effective carriers for delivering carotenoids, with significant application potential in the food industry.

Preparation and characterization of high-methoxyl pectin/glycerides emulsion for pH-responsive, targeting, and sustained release of fat-soluble substances

In this study, a pH-responsive emulsion system was prepared, combining high-methoxyl pectin (HMP) with camellia oil glycerides (CG). The emulsion was characterized as O/W type, with HMP serving as the wall material and CG as the oil phase. The physicochemical properties, pH responsiveness, digestion stability, and encapsulated delivery capabilities of the HMP-CG emulsion were investigated. The emulsion showed an average droplet size of 480.47 ± 76.19 nm, possessing a negative charge and a pronounced core-shell structure. HMP package CG enhanced hydrophilic ability and enabled targeted release within the small intestine through the structural changes of HMP. The presence of HMP and CG increased droplet dispersion and target digestibility of the emulsion system, leading to sustainable small intestine-specific release. Overall, HMP-CG emulsion system, composed of natural materials, exhibited the ability to achieve targeted and controllable release via pH-responsive mechanisms, offering an alternative for developing gel materials incorporating fat-soluble substances.

Difference in Allergenicity between β-Lactoglobulin in Bovine Milk and Caprine Milk is Related to Their Respective Digestive Stability.

The underlying cause of differences in sensitization between bovine and caprine milk β-lactoglobulin (β-LG) remains unclear. In this study, denatured forms of bovine and caprine milk β-LG were obtained through reductive alkylation and evaluated for allergenicity and digestibility in Balb/c mice. Results indicated weaker sensitization to nondenatured caprine milk β-LG compared to nondenatured bovine milk β-LG, with no significant difference in sensitization observed between denatured β-LG from both sources. The nondenatured β-LG of caprine milk and two types of denatured β-LG were degraded more rapidly than nondenatured bovine milk β-LG in the small intestine of mice. In terms of undenatured proteins, mouse intestinal tissues absorbed more bovine milk β-LG than caprine milk β-LG. Overall, structural disparities in β-LG between bovine and caprine milk resulted in varying digestion rates. Moreover, the slower-degraded bovine milk β-LG and its enzymatic fragments facilitated easier absorption by the intestine, disrupting the Th1/Th2 balance and increasing susceptibility to severe allergic reactions in mice.

ACE inhibitory effect and saltiness-enhancing properties of chicken-derived umami peptides: Digestive stability, inhibition kinetics, multiple ligand docking and central composite design

Angiotensin-I-converting enzyme (ACE) inhibitory activity and saltiness-enhancing properties of chicken-derived umami peptides were investigated. DGGRYY and NEFGYSNR were screened and the IC50 values were 28.71 μM and 283.24 μM, indicating their potential as novel ACE inhibitors. DGGRYY and NEFGYSNR have good pH and thermal stability. After gastrointestinal digestion, the ACE-inhibitory activity of DGGRYY retained about 53 %, whereas NEFGYSNR retained about 57 %. The inhibition pattern of both peptides was determined to be uncompetitive, consisting with the result of multiple ligand docking that the binding sites were outside the ACE active pocket. Trp59, Tyr62, Asp121, Arg124, and Ser516 were the key binding sites that contributed to the total binding energy. In addition, saltiness and palatability models were established according to sensory analysis and central composite design. In 0.1 % ∼ 0.3 % NaCl solutions, the addition of DGGRYY and NEFGYSNR could enhance the salty intensity and compensate for the palatability loss caused by salt reduction.

Impact of κ-Carrageenan on the Freshwater Mussel (Solenaia oleivora) Protein Emulsion Gels: Gel Formation, Stability, and Curcumin Delivery.

Protein-based emulsion gels are an ideal delivery system due to their unique structure, remarkable encapsulation efficiency, and tunable digestive behavior. Freshwater mussel (Solenaia oleivora) protein isolate (SoPI), an emerging sustainable protein with high nutritional value, possesses unique value in the development of functional foods. Herein, composite emulsion gels were fabricated with SoPI and κ-carrageenan (κ-CG) for the delivery of curcumin. SoPI/κ-CG stabilized emulsions possessed a high encapsulation efficiency of curcumin with a value of around 95%. The addition of κ-CG above 0.50% facilitated the emulsion gel formation and significantly improved the gel strength with 1326 g. Furthermore, the storage and digestive stability of curcumin were significantly improved as the κ-CG concentration increased. At 1.50% κ-CG, around 80% and 90% curcumin remained after 21-day storage at 45 °C and the 6 h in vitro gastrointestinal digestion, respectively. The addition of 0.50% κ-CG obtained the highest bioaccessibility of curcumin (~60%). This study illustrated the potential of SoPI emulsion gels as a carrier for stabilizing and delivering hydrophobic polyphenols.

Thermodynamics-driven metabolic and microbial preference for lactate methanization at different operational temperatures

Lactate-dominant organic acids released from acidified feedstocks inhibit anaerobic digestion processes, which can result in decreased biomethane (CH4) yield or even complete process failure. Herein, this study focus on exploring the effects of temperature (35 °C, 38 °C, 41 °C, 44 °C, 47 °C, 50 °C, and 55 °C) on the thermodynamics of microbial communities to assess the thermodynamics or microbial flora in driving the concurrent bioreactions involved in organic acid degradation. The findings revealed a prevalence of species such as Syntrophaceticus schinkii, DTU014, and Methanosarcina at 38 °C-44 °C. These species are known for their abilities in propionate and butyrate degradations, acetate oxidation, and methanation, respectively. Conversely, at thermophilic temperatures (47 °C, 50 °C, and 55 °C), this study observed higher abundance of thermophilic microorganisms like Defluviitoga and Methanoculleus, although these organisms are adapted to higher temperatures, their lactate utilization and methane production were less efficient than mesophilic species. Despite higher ΔG values for lactate, propionate, and butyrate degradation at 38 °C–44 °C compared with thermophilic temperatures, the relative abundance of functional enzymes (specifically, propionate and butyrate degrading enzymes) was found to be marginally higher than 47 °C–55 °C. As a result, 41 °C–44 °C induced remarkable thermodynamic effects that not only facilitated organic acid degradation but also promoted subsequent methanation, indicating the suitability of these temperatures for the methanation of biowaste acidified by lactate. Overall, this study provides insight into the temperature-dependent response of organic acid degradation, specifically focusing on the mechanisms involved in overcoming energy barriers, shaping the microbial flora, and ultimately improving the efficiency and stability of anaerobic digestion, especially for lactate-acidified feedstock.