Gastrointestinal Digestion Conditions Research Articles

Characterization and in vitro bioaccessability of optimized chia oil-Capsul-sodium alginate microparticles obtained by 3 nozzle spray-drying

The influence sodium alginate (SA) as an outer layer agent on bioaccessibility and matrix food release of purified chia oil (PCO) microencapsulated was investigated. PCO microparticles with Capsul were elaborated and optimized by response surface methodology (RSM), and then as an encapsulating agent and SA as an outer layer (PCO-Capsul/SA) were designed by mini spray-drying with 2 fluid nozzle (2-N) and 3 fluid nozzle (3-N). The optimal conditions obtained for PCO-Capsul system were: dryer inlet temperature of 114 °C and PCO:Capsul relation of 1:5.42. After the addition of SA out layer, PCO-Capsul/SA microparticles were subjected to in vitro static gastrointestinal digestion. PCO-Capsul/SA occurred mainly in the intestinal phase, showing the suitability of SA as an intestine-site release polymer. However, when PCO-Capsul/SA was incorporated into a yoghurt (Y), microparticles showed a significantly lower PCO matrix food release and bioaccessibility after in vitro digestion than PCO-Capsul-Y microparticles, due to their interaction between SA and Y. SA spray-dried by 3-N showed great potential for vehiculation of omega-3 rich oils in the future incorporation and develop of functional foods. Tweetable abstractThis research shows the role of the sodium alginate incorporation by 3 nozzle spray dryer when the design of an intestine-delivery food ingredient is intended.

Electrophoresis analysis and specific IgE-binding capacity of C18 unsaturated fatty acid-milk protein complexes during in vitro gastrointestinal digestion

The main whey allergenic proteins in bovine milk are α-lactalbumin (BLA) and β-lactoglobulin (BLG). When people consume bovine milk, BLA and BLG bind to C18 unsaturated fatty acids (UFA) in the matrix and form fatty acid-milk protein complexes. In this study, we explored the digestive stability of fatty acid-milk protein complexes by simulating infant and adult gastrointestinal digestion conditions and assessed the effects of C18 UFA on milk protein allergenicity. Our findings revealed that the optimal pH digestion for milk proteins in infants and adults was pH 3.0 and pH 2.0, respectively. The tricine-SDS-PAGE and IgE-binding capacity results revealed that the complexes were not easily degraded during digestion resistance, and the digestion products had strong IgE-binding capacity. Therefore, C18 UFA make milk proteins resistant to digestion, thereby increasing their allergenicity.

Fermented blend from sunflower seed press-cake and bovine sweet whey: Protein breakdown during in vitro gastrointestinal digestion

Sustainable food production implements circular economic system, valuing side streams and minimizing waste. This study was aimed to develop a new food by fermenting a blend of dehulled sunflower seed protein powder (SSPP) and reconstituted bovine sweet whey powder (RSWP). Blends were inoculated with Lactococcus lactis B12 alone or in association with Saccharomyces cerevisiae L12, and fermentation proceeded until reaching pH 4.8. After in vitro static gastrointestinal digestion, RSWP and SSPP proteins were highly proteolyzed and the soluble nitrogen content was 69–71% of total nitrogen. In digests, 42–75 unique peptides were identified, and most of them weighed 500–1000 Da. Free amino acids accounted for 202–228 mg/g protein in digests. Few bioactive peptides derived from RSWP were identified. These findings demonstrated strong degradability of RSWP and SSPP proteins during digestion and shed light on nutritional properties exploitable for food applications of the developed fermented blend.

Preparation, characterization and microencapsulation of walnut (Juglans regia L.) peptides-zinc chelate.

In this research, a novel kind of walnut (Juglans regia L.) peptides-zinc (Zn-WPs) chelate was obtained using the mass ratio of the walnut peptides (WPs) to ZnSO4.7H2O of 3.5:1 at pH 8.5 and 50°C for 84min, with the chelation rate of 84.5%. In comparison to walnut peptides (WPs), the contents of aspartic acid and glutamic acid in Zn-WPs chelate are approximately 27%, indicating that hydrophilic amino acids predominantly bind with walnut peptides. Following chelation with zinc ions, the ultraviolet-visible (UV) characteristic absorption peak shifted from 213nm to 210nm, while the average particle size of the chelate increased to 8.0±0.14µm, presenting a loose spherical structure under scanning electron microscopy. These findings suggest the formation of new substances. Fourier-transform infrared spectroscopy (FTIR) revealed carboxyl, amino, and peptide bonds as the chelation sites of WPs and zinc. The IC50 of walnut peptides-zinc (Zn-WPs) chelate is 2.91mg/mL, indicative of a favorable DPPH radical scavenging rate. Furthermore, Zn-WPs chelate microcapsules were produced via the spray drying method, achieving an encapsulation rate of 75.67±0.83% under optimal conditions. These microcapsules demonstrate robust stability across diverse environmental conditions. This study underscores the potential of Zn-WPs and its chelate microcapsules to enhance stability and bioactivity under varying circumstances. PRACTICAL APPLICATION: In this study, a new walnut peptide-zinc (Zn-WPs) chelate was prepared. The presence of zinc ions changes the structure and properties of walnut peptides and improves its stability. The production of Zn-WPs chelate microcapsules enables Zn-WPs to have strong in vitro stability under different pH and simulated gastrointestinal digestion conditions. These results provide novel insights for developing the walnut peptides as bioactive ingredients in functional foods.

In vitro gastrointestinal digestion of cow’s and sheep’s dairy products: Impact of species and structure

Sheep’s milk (SM) is known to differ from cow’s milk (CM) in nutritional composition and physicochemical properties, which may lead to different digestion behaviours. This work aimed to investigate the impact of the species (cow vs sheep) and the structure (milk vs yogurt) on the digestion of dairy products. Using an in vitro static gastrointestinal digestion model, CM, SM, cow’s milk yogurt (CY) and sheep’s milk yogurt (SY) were compared on particle size evolution, microscopic observations, degree of lipolysis, degree of proteolysis, specific protein degradation and calcium bioaccessibility. Species and structure affected particle size evolution during the gastric phase resulting in smaller particles for yogurts compared to milks as well as for CM products compared to SM products. Species impacted lipid composition and lipolysis, with SM products presenting higher short/medium-chain fatty acids content and higher intestinal degree of lipolysis. Proteolysis was influenced by structure, with milks showing higher intestinal degree of proteolysis compared to yogurts. Caseins were digested faster in CM, ⍺-lactalbumin was digested faster in SM despite its higher concentration, and during gastric digestion β-lactoglobulin was more degraded in CM products compared to SM products and more in yogurts compared to milks. Lastly, SM products released more bioaccessible calcium than CM products. In conclusion, species (cow vs sheep) impacted more the digestion compared to the structure (milk vs yogurt). In fact, SM was different from CM mainly due to a denser protein network that might slow down the accessibility of the enzyme to its substrate which induce a delay of gastric disaggregation and thus lead to slower the digestion of the nutrients.

Can Storage Stability and Simulated Gastrointestinal Behavior Change the Cytotoxic Effects of Concentrated Guava Leaves Extract against Human Lung Cancer Cells?

The influence of storage stability and simulated gastrointestinal behavior of different extracts of guava leaves extracts (NC: not concentrated, and C10 and C20: concentrated by nanofiltration) was evaluated based on their total phenolic compound (TPC) contents and antioxidant activity as well as on their cytotoxic effects on A549 and Vero cells. The results showed that C10 and C20 presented high stability for 125 days probably due to their high TPC contents and antioxidant activity. The simulated gastrointestinal behavior modified their TPC contents; however, after all digestion steps, the TPC values were higher than 70%, which means that they were still available to exert their bioactivities. Additionally, the cytotoxic effects of these extracts were evaluated before and after the simulated gastrointestinal behavior or under different storage conditions. C10 presented the best selectivity indices (SI) values (IC50 Vero cells/IC50 A549 cells) at both conditions suggesting that it can be considered a potential extract to be developed as a functional food due to its resistance to the gastrointestinal digestion and storage conditions tested.

Impact of In Vitro Gastrointestinal Digestion on the Phenolic Bioaccessibility and Bioactive Properties of Insect-Containing Beef Burgers.

Mealworm, migratory locust, and house cricket have recently been recognized by the European Commission as novel foods, thus being suitable in different food applications. In this work, we tested their powders as meat extenders at 5% (w/w) inclusion in beef burgers, considering their ability to vehicle phenolic compounds during simulated in vitro static gastrointestinal digestion (INFOGEST). Insect powders were abundant in different phenolic classes, recording the highest values in locust (LP; 314.69 mg/kg), followed by cricket (CP; 113.3 mg/kg) and mealworm (MWP; 51.9 mg/kg). Following a pan-cooking process, LP burgers were confirmed as the best source of phenolics, with a marked abundance of flavonoids and phenolic acids. Interestingly, the insect powders were found to affect the in vitro gastrointestinal bioaccessibility of phenolic compounds when compared with the CTR burger, likely promoted by the interactions between the phenolic compounds and proteins characterizing the tested insect powders. Among the most discriminant phenolic metabolites at the gastrointestinal level, we found several phenolic acids (mainly hydroxycinnamics), recording the highest content for the digested CP-containing burgers. Finally, stilbenes showed significant correlation values at the intestinal level with both antioxidant and enzymatic activities, while total flavonoids were the most correlated with the inhibition of acetylcholinesterase. Taken together, our preliminary findings demonstrated that insect powders added to beef burgers can promote the bioaccessibility and potential bioavailability of phenolics in the distal tracts of the intestine.

Effect of Mollusca shell extracts on inhibition of kimchi over-acidification

Mollusca species shell such as oyster shell (OS) and snail shell (SS), are discarded after taking the meat, and the discarded shell causes the environmental problems. Therefore, recycling shell waste could potentially eliminate the environmental problems. This study aimed to evaluate the potential of OS and SS as natural calcium resources. The minerals, calcium, magnesium, potassium, phosphorus and sodium were analyzed in OS and SS extracts. Among them, the calcium content was the highest: 36.87 (%) and 33.42 (%) in the OS and SS extracts, respectively. Further, the content of ionized bioavailable form of calcium in OS and SS was higher than that of CaCO3 under simulated gastrointestinal digestion conditions. Additionally, OS and SS were added to kimchi, and their inhibitory effect on kimchi acidification was evaluated by assessing pH, titratable acidity and microbial analysis. As the results indicated that the addition of OS and SS had little effect on inhibiting the growth of lactic acid bacteria. However, it was confirmed that calcium neutralizes the organic acids produced during fermentation. Overall, the results of this study provide preliminary information on the re-use of OS and SS extracts as ionized natural calcium supplements and fermentation retardants.

The Effect of Different Grape Varieties and Adding Different Ratios of Mustard Seeds on the Phenolic Compounds, Antioxidant Capacity, and Bioaccessibility Values of Hardaliye under In Vitro Digestion

Hardaliye, grape-based fermented beverage, rich in antioxidant phenolic compounds. Bioaccessibility and antioxidant capacity of bioactive compounds in hardaliye, produced using varying amounts of mustard seeds (1%, 1.5%, and 2%) with Merlot and Papazkarası grape varieties, were evaluated under in vitro gastrointestinal digestion conditions. After digestion, Merlot and Papazkarası samples with 2% addition of mustard seed showed significantly higher total phenolic compounds (TPC) (358.48±14.73 and 89.01±2.42 mg GAE/L, respectively) compared to other samples (P<0.05). 2% mustard seed added Merlot samples resulted in the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) and cupric reducing antioxidant capacity (CUPRAC) values (19.06±3.91 and 9.96±1.83 mmol TEAC/L, respectively) which differed significantly from other samples (P<0.05). The Merlot sample with 2% addition of mustard seed showed significantly higher TPC, total flavonoid compounds (TFC), DPPH, and CUPRAC bioaccessibility values compared to other Merlot samples (P<0.05). For Papazkarası samples with 2% mustard seed addition, significant differences were observed only in terms of TPC and TFC bioaccessibility values (15.87±2.30% and 15.27±1.29%, respectively) compared to samples with 1% and 1.5% mustard seed addition (P<0.05). The study demonstrated that the bioaccessibility of bioactive compounds in hardaliye can vary depending on the grape variety and to some extent, the use of mustard seed. This suggests that the food matrix and interaction with other food matrices in the environment can affect the stability and bioavailability of bioactive compounds during simulated digestion.

Bioaccessibility of Vitamins and Minerals in Processed Tubers and Leaves of Manihot esculenta Crantz Varieties

Manihot esculenta Crantz (cassava) is an important food crop in developing nations, with its tubers and leaves being a source of ascorbic acid, thiamin, riboflavin, and niacin (vitamins) and calcium, iron, potassium, and zinc (minerals). Malnutrition prevalence in some Kenyan Counties that relied on cassava‐based diets has partly been attributed to processing methods and/or nutrient bioaccessibility. The study area Kilifi County grows Kibandameno and Tajirika cassava varieties and is on record for high prevalence of undernutrition. The levels of vitamins and minerals, and their bioaccessibility in raw, boiled, and deep‐fried tubers, and pounded then boiled leaves of Kibandameno and Tajirika cassava varieties were studied. Digestion was done using static gastrointestinal digestion prior to the determination of vitamins (by HPLC) and minerals (by AAS and AES). Bioaccessibility of both vitamins and minerals was significantly higher (P < 0.001) in boiled followed by deep‐fried and lowest in raw tubers. Bioaccessibility ranged between 27% (Fe)–85% (vitamin C) in boiled, 20% (Fe)–79% (vitamin B1) in deep‐fried, and 15% (Fe)–(72% (K) in raw tubers. Bioaccessibility in processed leaves was significantly higher (P < 0.001) than in raw. This ranged between 11% (Fe)–81% (vitamin B1) in processed and between 8% (Fe)–67% (K) in raw leaves. Processing therefore significantly reduced levels of ascorbic acid, thiamin, riboflavin, niacin, calcium, iron, potassium, and zinc in raw tubers and leaves of Kibandameno and Tajirika Manihot esculenta Crantz varieties. Their bioaccessibility however significantly increased, being higher in tubers than in leaves.

Determination of Lactic Acid Bacteria Amount of Some Fermented Products Before and After Gastrointestinal Digestive Conditions

Fermente gıdalar, konakçı canlının bağırsağında canlı ve yeterli sayıda bulunduklarında konakçının sağlığını olumlu yönde etkileyen probiyotik mikroorganizmaları içeren gıdalardır. Bununla birlikte, bu gıdaların probiyotik mikroorganizma içermesi, “probiyotik gıda” olarak tanımlanmaları için yeterli değildir. Bu çalışma, yaygın olarak tüketilen bazı fermente ürünlerin laktik asit bakteri (LAB) sayısı ve simüle edilmiş gastrointestinal sindirim sonrası LAB sayılarını belirleyerek bu gıdaların probiyotik gıda olma potansiyellerini ortaya koymak ve tüketicilerde farkındalık oluşturmak için yapılmıştır. Çalışma sonucunda en yüksek LAB içeren fermente ürünler sırası ile endüstriyel kefir (7.52 log kob/g), geleneksel yapım kefir (6.99 log kob/g), geleneksel turşu (6.84 log kob/g), koyun sütünden yapılan ev yoğurdu (5.41 log kob/g), inek sütünden yapılan ev yoğurdu (4.76 log kob/g) olarak belirlenmiştir. Simüle edilmiş gastrointestinal sindirim sonrası LAB sayılarında en yüksek değerin ev yapımı kefir (5.01 log kob/g), endüstriyel kefir (4.1 log kob/g), koyun sütünden yapılmış ev yoğurdu (3.14 log kob/g) ve geleneksel turşu (2 log kob/g) olduğu ortaya konulmuştur. Sonuç olarak kefirin yüksek oranda LAB içerdiği tespit edilmiştir. Simüle edilmiş sindirim sonrasında da LAB miktarının büyük bir kısmının korunduğu belirlenmiştir. Kefirin probiyotik gıda olma potansiyelinin olduğu ve düzenli tüketildiğinde probiyotiklerden beklenen etkiyi sağlayabileceği düşünülmüştür.

Astaxanthin encapsulation in soybean protein isolate-sodium alginate complexes-stabilized nanoemulsions: antioxidant activities, environmental stability, and in vitro digestibility.

Nanoemulsions (NEs) have been considered an effective carrier to protect environmentally labile bioactive compounds from degradation during food processing. Among the numerous types of NEs, biopolymer-stabilized NEs have gained much attention to achieve this function because of the extensive sources, biocompatibility, and tunability. Therefore, the antioxidant activities, environmental stability, and in vitro digestibility of astaxanthin (AST)-loaded soybean protein isolate (SPI)-alginate (SA) complexes-stabilized NEs (AST-SPI-SA-NEs) were investigated in this study. The AST-SPI-SA-NEs exhibited an encapsulation efficiency of 88.30 ± 1.67%, which is greater than that of the AST-loaded SPI-stabilized NEs (AST-SPI-NEs) (77.31 ± 0.83%). Both AST-SPI-SA-NEs and AST-SPI-NEs exhibited significantly stronger hydroxyl or diphenylpicryl-hydrazyl radical-scavenging activities than the free AST. The formation of SPI-SA complexes strengthened the thermal, light, and storage stability of AST-SPI-SA-NEs with no apparently increasing mean diameter (around 200 nm). AST-SPI-SA-NEs also exhibited a better freeze-thaw dispersibility behavior than AST-SPI-NEs. AST-SPI-SA-NEs were more stable than AST-SPI-NEs were under in vitro gastrointestinal digestion conditions and exhibited a greater bioaccessibility (47.92 ± 0.42%) than both AST-SPI-NEs (12.97 ± 1.33%) and free AST (7.87 ± 0.37%). Hydrogen bonding was confirmed to participate in the formation of AST-SPI-SA-NEs and AST-SPI-NEs based on the molecular docking results. The construction of SPI-SA-NEs is conducive to the encapsulation, protection, and absorption of AST, providing a promising method for broadening the application of AST in processed foods or developing novel ingredients of functional foods. © 2023 Society of Chemical Industry.

The effect of different meat types on the in vitro digestibility of starch and protein in meat noodles

The incorporation of meat into noodles and pasta has the potential to enhance their nutritional qualities, flavor, aroma, and taste. This study aimed to investigate the digestibility of three types of meat noodles prepared using chicken breast (CN, CTN) and shrimp meat (SN) as raw materials, and compare them with commercial semolina dried noodles (CON). A simulated static gastrointestinal digestion model was employed and the changes in physical properties, starch digestibility, and protein digestibility during digestion were monitored. The results showed that all meat noodles exhibited prolonged digestion time compared to CON, especially for the formulation containing tomato powder (CTN) showing a higher amount of remaining solids throughout the entire digestion process. CON showed significantly higher free glucose content and lower free amino acids at the end of digestion compared to meat noodles. There were no significant differences in remaining solids and starch digestibility between CN and SN, although SN provided less digestible peptides and exhibited lower elastic modules due to its lower protein content. These findings shed light on the digestibility of meat noodles and offer valuable guidance for the industry in selecting suitable meat sources to produce instant diet options that are high in protein and well-balanced nutritionally.

A green and fast microwave-assisted synthesis of selenium nanoparticles and their characterization under gastrointestinal conditions using mass spectrometry.

We present a novel microwave-assisted green synthesis of selenium nanoparticles (SeNPs) using yeast extract as source of a non-toxic reducing and capping agents. Effects of synthesis and gastrointestinal digestion conditions on the biogenic Se particle size distribution and number concentration using SP ICP MS were evaluated. The median equivalent diameter of SeNPs varied depending on the synthesis conditions. Upon incubation in simulated gastric juice, the increase of SeNPs size was observed, whereas after simulated intestinal juice addition, their size came back close to the initial value. The biomolecules contained in yeast extract, which play predominant role in the synthesis of SeNPs, were identified by non-targeted qualitative analysis using LC Orbitrap ESI MS. The use of the state-of-the-art MS techniques allowed both the comprehensive assessment of the processes leading to the SeNPs formation and the evaluation of their behavior under gastrointestinal conditions which is of utmost importance for their use as a novel selenium source.

Effect of starch-based nanoparticles on the viability and stability of probiotics under adverse conditions

ABSTRACT Starch nanoparticles resist digestion in the upper intestine but not in the colon. They are proven to exert prebiotic effects on the human body. Starch-based nanoparticles have generated a great interest in the food and agriculture sector due to their biocompatibility, wide array of natural sources and ease of modification. In the current study, two starch sources (rice and water chestnut) were used to synthesize nanoparticles for the encapsulation of probiotic bacteria. Obtained nanoparticles were characterized for their morphological, molecular, and structural attributes using Fourier Transform Infrared Spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD), and zeta sizer. Furthermore, free and nano-encapsulated probiotics were subject to simulated gastrointestinal digestion conditions. The average size of rice and water chestnut starch-based nano-capsules ranged from 309 to 427 nm. The encapsulation efficiency was recorded for rice and water chestnut starch as 89% and 95%, respectively. SEM micrographs exhibited entrapment of probiotics in wall materials. The surface of the capsules showed tiny, smooth surface polygonal granules. XRD images showed loss of crystallinity structure following encapsulation. Higher probiotic viability was recorded under simulated gastrointestinal conditions for nano-encapsulated probiotics compared to free probiotics. Conclusively, water chestnut and rice-based starch nanoparticles showed overall the best results regarding the viability of probiotics under stressed conditions.

Effect of protein-based nanoencapsulation on viability of probiotic bacteria under hostile conditions

ABSTRACT The present study aimed to evaluate the effect of the incorporation of protein-based nanoencapsulation on the viability and stability of probiotic Lactobacillus rhamnosus in digestion conditions and model food. In the study’s first phase, protein-based nanoparticles were prepared by the pH cycling method, and then the probiotic, Lactobacillus rhamnosus, was nano-encapsulated. Two types of proteins, namely, whey protein and zein protein, were used to encapsulate probiotics individually. The obtained nano-encapsulated probiotics were characterized by performing particle size, SEM, FTIR, and in vitro assay was performed. Then, free and nano-encapsulated probiotics were added to the model food (yogurt) and analyzed for microbiological and sensory evaluation. Nanoencapsulation with both types of proteins significantly (p < .05) improved the stability and viability of Lactobacillus rhamnosus. The particle size for whey and zein nano-encapsulated probiotics ranged between 96 and 100 nm. The encapsulation efficiency for whey and zein nanoparticles was recorded at 96% and 87%, respectively. SEM images for both zein and whey nanoparticles showed their irregular spherical structure. FTIR spectra suggested that the mechanism of entrapment involved in water-insoluble or physical properties was mostly responsible for the generated loaded nanoparticle. In vitro analysis illustrated that whey nanoencapsulation showed the highest viability in SGC and SIC, followed by zein nanoencapsulation and free probiotics showed the minimum viability. Protein nanoencapsulation also significantly affected the sensory properties of food products. Conclusively, the nanoencapsulation of probiotics using protein nanoparticles helps prolong the viability and stability of probiotics under-simulated gastrointestinal digestion conditions and in yogurt.

Co-encapsulation of curcumin and quercetin with zein/HP-β-CD conjugates to enhance environmental resistance and antioxidant activity

In this study, composite nanoparticles consisting of zein and hydroxypropyl beta-cyclodextrin were prepared using a combined antisolvent co-precipitation/electrostatic interaction method. The effects of calcium ion concentration on the stability of the composite nanoparticles containing both curcumin and quercetin were investigated. Moreover, the stability and bioactivity of the quercetin and curcumin were characterized before and after encapsulation. Fluorescence spectroscopy, Fourier Transform infrared spectroscopy, and X-ray diffraction analyses indicated that electrostatic interactions, hydrogen bonding, and hydrophobic interactions were the main driving forces for the formation of the composite nanoparticles. The addition of calcium ions promoted crosslinking of the proteins and affected the stability of the protein–cyclodextrin composite particles through electrostatic screening and binding effects. The addition of calcium ions to the composite particles improved the encapsulation efficiency, antioxidant activity, and stability of the curcumin and quercetin. However, there was an optimum calcium ion concentration (2.0 mM) that provided the best encapsulation and protective effects on the nutraceuticals. The calcium crosslinked composite particles were shown to maintain good stability under different pH and simulated gastrointestinal digestion conditions. These results suggest that zein–cyclodextrin composite nanoparticles may be useful plant-based colloidal delivery systems for hydrophobic bio-active agents.

Induced Expression of the Acinetobacter sp. Oxa Gene in Lactobacillus acidophilus and Its Increased ZEN Degradation Stability by Immobilization.

Zearalenone (ZEN, ZEA) contamination in various foods and feeds is a significant global problem. Similar to deoxynivalenol (DON) and other mycotoxins, ZEN in feed mainly enters the body of animals through absorption in the small intestine, resulting in estrogen-like toxicity. In this study, the gene encoding Oxa, a ZEN-degrading enzyme isolated from Acinetobacter SM04, was cloned into Lactobacillus acidophilus ATCC4356, a parthenogenic anaerobic gut probiotic, and the 38 kDa sized Oxa protein was expressed to detoxify ZEN intestinally. The transformed strain L. acidophilus pMG-Oxa acquired the capacity to degrade ZEN, with a degradation rate of 42.95% at 12 h (initial amount: 20 μg/mL). The probiotic properties of L. acidophilus pMG-Oxa (e.g., acid tolerance, bile salt tolerance, and adhesion properties) were not affected by the insertion and intracellular expression of Oxa. Considering the low amount of Oxa expressed by L. acidophilus pMG-Oxa and the damage to enzyme activity by digestive juices, Oxa was immobilized with 3.5% sodium alginate, 3.0% chitosan, and 0.2 M CaCl2 to improve the ZEN degradation efficiency (from 42.95% to 48.65%) and protect it from digestive juices. The activity of immobilized Oxa was 32-41% higher than that of the free crude enzyme at different temperatures (20-80 °C), pH values (2.0-12.0), storage conditions (4 °C and 25 °C), and gastrointestinal simulated digestion conditions. Accordingly, immobilized Oxa could be resistant to adverse environmental conditions. Owing to the colonization, efficient degradation performance, and probiotic functionality of L. acidophilus, it is an ideal host for detoxifying residual ZEN in vivo, demonstrating great potential for application in the feed industry.

Evaluation of pomegranate (Punica granatum) peel for bioaccessibility of polyphenols and prebiotic potential using in vitro model

This research evaluated the bioaccessibility of polyphenols and prebiotic potential of pomegranate peel powder (PPP) on an in vitro model of static gastrointestinal digestion (IVD) combined with a colonic fermentation assay using L. acidophilus. After the IVD, the TPC, TFC, FRAP, DPPH-RSA, and ABTS-RSA were significantly different (p ≤ 0.05) at each digestion phase. Furthermore, the recovery of TPC and TFC after intestinal digestion was profoundly affected (p ≤ 0.05) by salivary or gastric digestion phases by 52.47 and 20.34%, correspondingly. The bioaccessibility values were 34.40 and 30.35%, respectively. Residual intestinal digestibility index (RID) values were 34.36 and 14.16%, respectively. There was a strong correlation (between polyphenolic compounds and antioxidant capacity at each digestion phase. PPP is revealed to be an excellent source of microbial substrates at the level of the large intestine; hence, it is a potential prebiotic. Moreover, PPP is an excellent source of fiber and has high functional properties; thus, it might be utilized in the food industry as a functional ingredient or as a nutraceutical that promotes health.

In vitro antidiabetic and antihypercholesterolemic activities of camel milk protein hydrolysates derived upon simulated gastrointestinal digestion of milk from different camel breeds

Milk protein hydrolysates derived from 4 camel breeds (Pakistani, Saheli, Hozami, and Omani) were evaluated for in vitro inhibition of antidiabetic enzymatic markers (dipeptidyl peptidase IV and α-amylase) and antihypercholesterolemic enzymatic markers (pancreatic lipase and cholesterol esterase). Milk samples were subjected to in vitro simulated gastric (SGD) and gastrointestinal digestion (SGID) conditions. In comparison with intact milk proteins, the SGD-derived milk protein hydrolysates showed enhanced inhibition of α-amylase, dipeptidyl peptidase IV, pancreatic lipase, and cholesterol esterase as reflected by lower half-maximal inhibitory concentration values. Overall, milk protein hydrolysates derived from the milk of Hozami and Omani camel breeds displayed higher inhibition of different enzymatic markers compared with milk protein hydrolysates from Pakistani and Saheli breeds. In vitro SGD and SGID processes significantly increased the bioactive properties of milk from all camel breeds. Milk protein hydrolysates from different camel breeds showed significant variations for inhibition of antidiabetic and antihypercholesterolemic enzymatic markers, suggesting the importance of breed selection for production of bioactive peptides. However, further studies on identifying the peptides generated upon SGD and SGID of milk from different camel breeds are needed.