Blood-brain barrier transport and neuroprotective potential of blackberry-digested polyphenols: an in vitro study.
Figueira Inês,Tavares Lucélia,Jardim Carolina,Costa Inês,Terrasso Ana P,Almeida Andreia F,Govers Coen,Mes Jurriaan J,Gardner Rui,Becker Jörg D,McDougall Gordon J,Stewart Derek,Filipe Augusto,Kim Kwang S,Brites Dora,Brito Catarina,Brito M Alexandra,Santos Cláudia N
European journal of nutrition
PURPOSE:Epidemiological and intervention studies have attempted to link the health effects of a diet rich in fruits and vegetables with the consumption of polyphenols and their impact in neurodegenerative diseases. Studies have shown that polyphenols can cross the intestinal barrier and reach concentrations in the bloodstream able to exert effects in vivo. However, the effective uptake of polyphenols into the brain is still regarded with some reservations. Here we describe a combination of approaches to examine the putative transport of blackberry-digested polyphenols (BDP) across the blood-brain barrier (BBB) and ultimate evaluation of their neuroprotective effects. METHODS:BDP was obtained by in vitro digestion of blackberry extract and BDP major aglycones (hBDP) were obtained by enzymatic hydrolysis. Chemical characterization and BBB transport of extracts were evaluated by LC-MS. BBB transport and cytoprotection of both extracts was assessed in HBMEC monolayers. Neuroprotective potential of BDP was assessed in NT2-derived 3D co-cultures of neurons and astrocytes and in primary mouse cerebellar granule cells. BDP-modulated genes were evaluated by microarray analysis. RESULTS:Components from BDP and hBDP were shown to be transported across the BBB. Physiologically relevant concentrations of both extracts were cytoprotective at endothelial level and BDP was neuroprotective in primary neurons and in an advanced 3D cell model. The major canonical pathways involved in the neuroprotective effect of BDP were unveiled, including mTOR signaling and the unfolded protein response pathway. Genes such as ASNS and ATF5 emerged as novel BDP-modulated targets. CONCLUSIONS:BBB transport of BDP and hBDP components reinforces the health benefits of a diet rich in polyphenols in neurodegenerative disorders. Our results suggest some novel pathways and genes that may be involved in the neuroprotective mechanism of the BDP polyphenol components.
In vitro bioaccessibility of proteins and lipids of pH-shift processed Nannochloropsis oculata microalga.
Cavonius L R,Albers E,Undeland I
Food & function
The pH-shift process fractionates biomass into soluble proteins and insoluble fractions, followed by precipitation and recovery of the solubilized proteins. Nannochloropsis oculata in seawater was subjected to the pH-shift process, followed by digestion of various intermediates and product fractions of the process, using the Infogest in vitro digestion model (Minekus et al., 2014) with added gastric lipase. As measures for protein and lipid accessibility, degrees of protein hydrolysis and fatty acid liberation were assessed post-digestion and compared to the amounts of peptide bonds and total fatty acids present in the raw materials. Results showed that neither proteins nor lipids of intact Nannochloropsis cells were accessible to the mammalian digestive enzymes used in the digestion model. Cell disruption, and to a lesser extent, further pH-shift processing with protein solubilisation at pH 7 or pH 10, increased the accessibility of lipids. For proteins, differences amongst the pH-shift processed materials were non-significant, though pre-freezing the product prior to digestion increased the accessibility from 32% to 47%. For fatty acids, pH-shift process-products gave rise to 43% to 52% lipolysis, with higher lipolysis for products solubilised at pH 10 as opposed to pH 7. Our results indicate the importance of processing to produce an algal product that has beneficial nutritional properties when applied as food or feed.
Bioaccessibility and Bioavailability of a Marine-Derived Multimineral, Aquamin-Magnesium.
Felice Valeria D,O'Gorman Denise M,O'Brien Nora M,Hyland Niall P
Magnesium is an essential mineral involved in a range of key biochemical pathways. Several magnesium supplements are present on the market and their degree of bioavailability differs depending on the form of magnesium salt used. Aquamin-Mg is a natural source of magnesium, containing 72 additional trace minerals derived from the clean waters off the Irish coast. However, the in vitro bioaccessibility and bioavailability of Aquamin-Mg in comparison with other supplement sources of magnesium has yet to be tested. Aquamin-Mg, magnesium chloride (MgCl₂) and magnesium oxide (MgO) were subjected to gastrointestinal digestion according to the harmonized INFOGEST in vitro digestion method and in vitro bioavailability tested using the Caco-2 cell model. Magnesium concentration was measured by atomic absorption spectrophotometry (AAS). Magnesium recovery from both Aquamin-Mg and MgCl₂ was greater than for MgO. Magnesium from all three sources was transported across the epithelial monolayer with Aquamin-Mg displaying a comparable profile to the more bioavailable MgCl₂. Our data support that magnesium derived from a marine-derived multimineral product is bioavailable to a significantly greater degree than MgO and displays a similar profile to the more bioavailable MgCl₂ and may offer additional health benefits given its multimineral profile.
Mass spectrometry data of and pig digestion of skim milk powder.
Egger Lotti,Schlegel Patrick,Baumann Christian,Stoffers Helena,Guggisberg Dominik,Brügger Cédric,Dürr Desirée,Stoll Peter,Vergères Guy,Portmann Reto
Data in brief
The data in this article are related to the research article entitled "Physiological comparability of the harmonized INFOGEST digestion method to pig digestion" (Egger et al., 2012). In this article, proteins identified in the different sections of pig skim milk powder (SMP) digestion are presented. In addition to the exemplary β-casein profiles of the paper, the peptide patterns of the other most abundant milk proteins during digestion in individual pigs are shown as heatmaps and line graphs. These data clearly reveal the digestion resistant protein regions and illustrate the variability between the pigs in the different sampling sections. Moreover, peptide patterns of the same SMP proteins comparing the harmonized digestion (IVD) with pig digestion show the physiological relevance of the IVD protocol. Finally, correlation coefficients were calculated to indicate similarities between pig sampling sections and gastric and intestinal IVD endpoints.
Effect of domestic cooking methods on protein digestibility and mineral bioaccessibility of wild harvested adult edible insects.
Manditsera Faith A,Luning Pieternel A,Fogliano Vincenzo,Lakemond Catriona M M
Food research international (Ottawa, Ont.)
Wild harvested edible insects are characterised by high protein and mineral contents with potential to contribute substantially to nutrition security. However, nutritional content is only beneficial when proteins are digestible and minerals bioaccessible. This study determined the effects of domestic processing on protein digestibility and mineral bioaccessibility of two wild harvested insect species: Eulepida mashona (beetle) and Henicus whellani (cricket). Samples of both insects were subjected to boiling, roasting, or combined boiling and roasting, imitating the way insects are traditionally prepared in Zimbabwe. Moreover, they were in vitro digested according to INFOGEST protocol. Boiling of both insects resulted in loss of protein as it leached into the boiling water. The raw insects had a higher protein in vitro digestibility than the boiled and roasted insects, and the maximal decrease in protein digestibility was around 25% for twice boiling of the beetles and for boiled and roasted crickets. For both insect species, boiling resulted in non-significant loss of iron and zinc. Iron was the least bioaccessible mineral in both insects, based on the concentrations of soluble mineral measured by ICP-AES. However, beetles had a much higher iron bioaccessibility (30.7%) as compared to crickets (8.11%). Interestingly, boiling resulted in about 50% decrease in iron and zinc bioaccessibility in both species while roasting did not. The reduced protein digestibility and mineral accessibility with processing can be explained by protein modification and interactions of minerals with other food components, such as chitin and phytochemicals. Because of the reduction in protein digestibility and mineral accessibility during boiling, roasting should be favoured over boiling and in any case short boiling time is recommended.
Chitosan reduces vitamin D bioaccessibility in food emulsions by binding to mixed micelles.
Tan Yunbing,Li Ruyi,Liu Chengzhen,Muriel Mundo Jorge,Zhou Hualu,Liu Jinning,McClements David Julian
Food & function
Consumption of sufficiently high quantities of dietary fibers has been linked to a range of health benefits. Recent research, however, has shown that some dietary fibers interfere with lipid digestion, which may reduce the bioavailability of oil-soluble vitamins and nutraceuticals. For this reason, we examined the impact of a cationic polysaccharide (chitosan) on the bioaccessibility of vitamin D using the standardized INFOGEST in vitro digestion model. The vitamin D was encapsulated within an emulsion-based delivery system that contained whey protein-coated corn oil droplets. Our results showed that chitosan promoted severe droplet flocculation in the small intestine and reduced the amount of free fatty acids detected using a pH-stat method. However, a back-titration of the digested sample showed that the lipids were fully digested at all chitosan levels used (0.1-0.5%), suggesting that chitosan may have bound some of the free fatty acids released during lipid digestion. The presence of the chitosan decreased the bioaccessibility of vitamin D by about 37%, but this effect did not depend strongly on chitosan concentration (0.1-0.5%). It was hypothesized that chitosan bound to the vitamin-loaded mixed micelles and promoted their precipitation. The knowledge gained in this study might provide useful insights in designing emulsion-based delivery systems with high vitamin bioaccessibility.
Stability of antibacterial and coccidiostat drugs on chicken meat burgers upon cooking and in vitro digestion.
Sobral M Madalena C,Romero-Gonzalez Roberto,Faria Miguel A,Cunha Sara C,Ferreira Isabel M P L V O,Garrido-Frenich Antonia
The impact of culinary practices - oven or microwave cooking combined with herbs and/or beer - on antibacterial and coccidiostat drugs stability and bioaccessibility in chicken meat was evaluated. Fourteen compounds from 6 classes (β-lactams, tetracyclines, sulfonamides, fluoroquinolones, macrolides, and coccidiostats) were monitored after cooking and in vitro digestion (INFOGEST protocol) at two fortification levels. Depending on their reduction, the presence of transformation products derived from cooking or digestion was investigated. In general, compounds were stable during cooking except amoxicillin, chlortetracycline and tylosin (reductions > 50%). Molecular rearrangement and dechlorination reactions are the most probable transformations derived from cooking. Adding herbs/beer does not benefit their reductions. During in vitro digestion, maximum bioaccessibilities of 60% were observed for all quantified compounds. As drugs and bile salts interact, increasing the absorption of lipophilic drugs, their bioaccessibility predictions must not be based only on the determination of their free form using LC-MS/MS.
In vitro digestion of complex foods: How microstructure influences food disintegration and micronutrient bioaccessibility.
Hiolle M,Lechevalier V,Floury J,Boulier-Monthéan N,Prioul C,Dupont D,Nau F
Food research international (Ottawa, Ont.)
Digestion is a mechanical and chemical process that is only partly understood, and even less so for complex foods. In particular, the issue of the impact of food structure on the digestion process is still unresolved. In this study, the fate of four micronutrient-enriched foods with identical compositions but different microstructures (Custard, Pudding, Sponge cake, Biscuit) was investigated using the 3-phase in vitro model of human digestion developed by the INFOGEST network. Matrix disintegration and hydrolysis of macronutrients (proteins, lipids and carbohydrates) were monitored during the three phases of digestion using biochemical techniques, size-exclusion chromatography, thin-layer chromatography and gas chromatography. Micronutrient release (vitamin B9 and lutein) was monitored using reverse-phase chromatography. Food structure did not greatly influence macronutrient hydrolysis, except for lipolysis that was four-times higher for Biscuit compared to Custard. However, the bioaccessibility of both micronutrients depended on the food structure and on the micronutrient. Vitamin B9 release was faster for Biscuit and Sponge cake during the gastric phase, whereas lutein release was higher for Custard during the intestinal step. Extensive statistical analysis highlighted the impact of food structure on the digestion process, with different digestion pathways depending on the food matrix. It also made it possible to characterise the gastric step as a predominantly macronutrient solubilisation phase, and the intestinal step as a predominantly hydrolysis phase.
Bioaccessibility and cellular uptake by Caco-2 cells of carotenoids and chlorophylls from orange peels: A comparison between conventional and ionic liquid mediated extractions.
Murador Daniella C,De Souza Mesquita Leonardo M,Neves Bruna V,Braga Anna R C,Martins Paula L G,Zepka Leila Q,De Rosso Veridiana V
Native extracts from orange peels were obtained by a conventional method using acetone and, an alternative method using ionic liquid (1-butyl-3-methylimidazolium chloride ([Cmim]Cl)). The bioaccessibilities and cellular uptakes of carotenoids, esters and chlorophylls were evaluated, since the influence of esterification on bioaccessibility and bioavailability is not well established. For this, the extracts were emulsified, submitted to in vitro simulated digestion model according to the INFOGEST protocol, followed by uptake by Caco-2 cells. Compounds were separated, identified and quantified by HPLC-PDA-MS/MS. After digestion, 22.0% and 26.2% of the total carotenoids and 45.9% and 68.7% of the chlorophylls were bioaccessible from the acetone and [Cmim]Cl extracts, respectively. The bioaccessibilities of xanthophylls and carotenes were significantly higher than those of the mono- and diesters. The uptake by Caco-2 cells varied from 130.2 to 131.9 ng/mg cell protein for total carotenoids and from 243.8 to 234.2 ng/mg cell protein for chlorophylls in the acetone and [Cmim]Cl extracts, respectively. In general, xanthophylls and esters were better absorbed than carotenes.
Simulated gastrointestinal digestion of amaranth flour and protein isolate: Comparison of methodologies and release of antioxidant peptides.
Rodríguez Mariela,García Fillería Susan F,Tironi Valeria A
Food research international (Ottawa, Ont.)
The effect of both the simulated gastrointestinal digestion conditions and the matrix over protein hydrolysis and antioxidant peptides generation was evaluated by comparing an in-house method with COST INFOGEST-based SGD protocols. The in-house protocol was used to digest amaranth protein isolate I (Id1), while the standardized method and a modified version (similar enzyme/substrate ratio than in our lab) were used to digest I and amaranth flour F (Id3 and Fd3, Id2 and Fd2). Protein hydrolysis degree (TNBS method) was similar for the three I digested (about 60%), but lower for F digested (45 and 34% for Fd2 and Fd3, respectively). The five digested obtained presented comparable protein solubility and only small differences in the polypeptide/peptide composition (SDS-PAGE, tricine-SDS-PAGE, gel filtration FPLC), similar antioxidant activity by the ORAC assay (IC values between 0.023 and 0.034 mg.mL) and some mild differences by the HORAC assay (IC values between 1.13 and 1.30 mg.mL for Id1, Fd2, and Fd3; 1.50 mg.mL for Id2; 1.61 mg.mL for Id3). All the FPLC fractions presented high ORAC activity, while only fractions between 0.43 and 3.5 kDa showed HORAC activity (due to peptide concentration). Differences in activity and potency among fractions were registered, especially for F digested. The modification of digestion conditions produced only small differences in the molecular composition but did not affect the proteolysis degree and the antioxidant activity in the case of digested from protein isolate. The presence of other components and changes in the digestion method had an impact on proteolysis, composition and antioxidant activity of flour digested.
Digestive Stability and Bioaccessibility of Antioxidants in Prickly Pear Fruits from the Canary Islands: Healthy Foods and Ingredients.
Gómez-Maqueo Andrea,Antunes-Ricardo Marilena,Welti-Chanes Jorge,Cano M Pilar
Antioxidants (Basel, Switzerland)
Although prickly pear fruits have become an important part of the Canary diet, their native varieties are yet to be characterized in terms of betalains and phenolic compounds. To exert potential health benefits, these antioxidants must be released from the food matrix and be stable in the gastrointestinal tract. Our aim was to characterize the betalain and phenolic profile of four prickly pear varieties from the Canary Islands (Spain) and determine their digestive stability and bioaccessibility via in vitro gastrointestinal digestion. Digestive studies were performed considering the (i) importance of the edible fraction (pulps) and (ii) potential of fruit peels as by-products to obtain healthy ingredients. Betalains and phenolic profiles were analyzed by HPLC-DAD-ESI/MS and HPLC-DAD-MS/QTOF. Pulps in Colorada and Fresa varieties presented high indicaxanthin and betanin content, respectively. Despite low pH in the gastric phase, betalains were stable to reach the intestinal phase, although indicaxanthin presented a higher bioaccessibility. Blanco Buenavista peels contained a distinct flavonoid profile including a new isorhamnetin-hexosyl-rhamnoside. Phenolic compounds were abundant and highly bioaccessible in fruit peels. These findings suggest that prickly pear pulps are rich in bioaccessible betalains; and that their peels could be proposed as potential by-products to obtain sustainable healthy ingredients.
A Brief Overview of Dietary Zeaxanthin Occurrence and Bioaccessibility.
Tudor Cristina,Pintea Adela
Molecules (Basel, Switzerland)
As it exhibits no provitamin A activity, the dietary intake of zeaxanthin is not considered essential. However, its contribution to ocular health has long been acknowledged. Numerous publications emphasize the importance of zeaxanthin alongside lutein in ocular diseases such as cataracts and age-related macular degeneration which constitute an important health concern, especially among the elderly. Considering that the average dietary ratio of lutein to zeaxanthin favors the first, more bioaccessible food sources of zeaxanthin that can hinder the development and progression of the above-mentioned disorders are of great interest. In this paper, a brief overview of the more recent state of knowledge as regards dietary sources together with their respective zeaxanthin bioaccessibility assessed through a standardized in vitro digestion method was provided.
In vitro gastrointestinal stability, bioaccessibility and potential biological activities of betalains and phenolic compounds in cactus berry fruits (Myrtillocactus geometrizans).
Montiel-Sánchez Mara,García-Cayuela Tomás,Gómez-Maqueo Andrea,García Hugo S,Cano M Pilar
Cactus berry (Myrtillocactus geometrizans) is a scarcely studied Mexican wild fruit. These fruits could contribute to reduce the risk of degenerative chronic diseases due to their bioactive profile. The aim of this work was to study the betalains and phenolic profile in cactus berry, their in vitro biological activities and gastrointestinal digestive stability and bioaccessibility. 43 metabolites were identified by HPLC-DAD-ESI-QTOF (8 betaxanthins, 8 betacyanins, 13 flavonoids, 6 phenolic acids). Phyllocactin and Isorhamnetin rhamnosyl-rutinoside (IG2) were the most abundant metabolites (5876 and 396 µg/g dw) which were also bioaccessible (16 and 21%, respectively). Pulps showed higher (p ≤ 0.05) antioxidant activity by the Oxygen Radical Absorbance Capacity (27 mM Trolox equivalents). The anti-hyperglycemic activity was highest (p ≤ 0.05) in peel and pulp tissues (85% α-glucosidase and 8% α-amylase inhibition). An 83% inhibition of hyaluronidase showed high anti-inflammatory activity. Cactus berry fruit should be considered a promising fruit candidate for a sustainable healthy diet.
Screening of critical factors influencing the efficient hydrolysis of zeaxanthin dipalmitate in an adapted in vitro- digestion model.
Wen Xin,Hempel Judith,Schweiggert Ralf M,Wang Yuxiao,Ni Yuanying,Carle Reinhold
As hydrolysis of carotenoid esters is believed to be highly efficient in vivo, their insufficient hydrolysis in in vitro-digestion models, particularly, regarding zeaxanthin diesters, is a current issue. Therefore, in this study, several factors related to the enzymatic hydrolysis were investigated in an adapted version of the standardized INFOGEST in vitro-digestion model, using zeaxanthin dipalmitate (ZDP) as a substrate. The results showed that pancreatic lipase was able to hydrolyze ZDP, whereas carboxyl ester lipase (CEL) substantially contributed to ZDP cleavage. Replacement of commonly used porcine with bovine bile extracts and the substitution of coffee creamer for soybean oil at identical fat contents both significantly improved hydrolysis efficiency and bioaccessibility of total zeaxanthin to better mimic in vivo conditions. Thus, bile and lipids selection for in vitro digestion of carotenoid esters was crucial. The combined use of coffee creamer, pancreatin, CEL, and bovine bile led to the highest hydrolysis efficiency of 29.5%.
Impact of high hydrostatic pressure and thermal treatment on the stability and bioaccessibility of carotenoid and carotenoid esters in astringent persimmon (Diospyros kaki Thunb, var. Rojo Brillante).
Cano M Pilar,Gómez-Maqueo Andrea,Fernández-López Rebeca,Welti-Chanes Jorge,García-Cayuela Tomás
Food research international (Ottawa, Ont.)
The carotenoid and carotenoid ester profile in astringent persimmon (Diospyros kaki Thunb., var. Rojo Brillante) was composed by 13 free xanthophylls, 8 hydrocarbon carotenes and 17 carotenoid esters. The stability and biaoccessibility of these carotenoids was determined by an adaptation of the INFOGEST protocol. Results showed that the stability of persimmon carotenoids ranged from 61 to 74%, depending on the digestion phase, being (all-E)-β-cryptoxanthin and (all-E)-antheraxanthin 3-O-palmitate the most stable carotenoids. At the final step of the digestion (oral + gastric + duodenal phase), only traces of (all-E)-antheraxanthin, (all-E)-lutein and (all-E)-β-cryptoxanthin were found in control samples due to the low efficiency of carotenoid micellization, which was affected by the high pectin content naturally present in persimmon tissues. Processing increased the overall carotenoid bioaccessibility to 54% in pressurized samples and to 25% in thermal treated ones. This effect depended on the processing technology as well as on the chemical structure of the carotenoid, being (all-E)-β-cryptoxanthin and (all-E)-β-cryptoxanthin laurate the most bioaccessible carotenoids in pressurized samples and (all-E)-β-cryptoxanthin laurate and (all-E)-antheraxanthin the most bioaccessible ones in pasteurized ones.
Factors impacting lipid digestion and β-carotene bioaccessibility assessed by standardized gastrointestinal model (INFOGEST): oil droplet concentration.
Tan Yunbing,Zhang Zhiyun,Zhou Hualu,Xiao Hang,McClements David Julian
Food & function
Food, nutrition, and pharmaceutical scientists are trying to elucidate the major factors impacting the bioavailability of macronutrients (e.g., lipids) and micronutrients (e.g., vitamins) so as to improve their efficacy. Currently, there is still a limited understanding of how food matrix effects impact digestion and bioaccessibility determined under the INFOGEST model, which is currently the most widely used standardized in vitro gastrointestinal model. Therefore, we examined the impact of corn oil concentration on lipid digestion and β-carotene bioaccessibility using model food emulsions. For all oil concentrations tested (2.5 to 20%), complete lipid digestion was achieved using fed-state gastrointestinal conditions, which could only be seen if a back-titration was performed. The particle size and negative surface potential on the mixed micelles formed at the end of the small intestine phase both increased with increasing oil concentration, which was attributed to the generation of more free fatty acids. The β-carotene bioaccessibility increased when the oil concentration was raised from 2.5 to 10% due to the increased solubilization capacity of the mixed micelles, but then it decreased when the oil concentration was raised further to 20% due to precipitation and sedimentation of some of the β-carotene. The maximum β-carotene bioaccessibility (93.2%) was measured at 10% oil. These results indicate that the oil concentration of emulsions influences β-carotene bioaccessibility by altering digestion, solubilization, and precipitation processes. This knowledge is important when designing more effective functional or medical food products.
Factors impacting lipid digestion and nutraceutical bioaccessibility assessed by standardized gastrointestinal model (INFOGEST): Emulsifier type.
Tan Yunbing,Zhang Zhiyun,Muriel Mundo Jorge,McClements David Julian
Food research international (Ottawa, Ont.)
This paper is part of a series examining the impact of the main factors influencing lipid digestion and nutraceutical bioaccessibility in β-carotene-loaded oil-in-water emulsions using the harmonized INFOGEST simulated gastrointestinal model. Here, the impact of emulsifier type was examined since food emulsions and nutraceutical delivery systems are often stabilized by various types of emulsifier. The INFOGEST method was adopted to investigate the in vitro gastrointestinal fate of emulsions stabilized by five kinds of food-grade emulsifier representing different classes: synthetic surfactants (Tween 20); natural surfactants (quillaja saponin); proteins (caseinate); polysaccharides (gum arabic); and phospholipids (soy lysolecithin). Microfluidization produced emulsions with small droplet sizes for all emulsifiers, except soy lysolecithin. Within the gastrointestinal model, the caseinate-coated oil droplets had the worst gastric stability, with severe droplet flocculation and coalescence occurring in the stomach. The fraction of the lipid phase that had been digested by the end of the gastrointestinal model was considerably lower for the emulsions stabilized by soy lysolecithin (93%) or caseinate (93%), than those stabilized by gum arabic (99%), quillaja saponin (111%) or Tween 20 (117%). This effect was attributed to lower surface area of lipids available for lipase to attach to for the lysolecithin and caseinate emulsions. The overall bioaccessibility of the β-carotene increased in this order: lysolecithin (25%) < gum arabic (51%) < caseinate (55%) < quillaja saponin (56%) < Tween 20 (62%). The impact of emulsifier type on carotenoid bioaccessibility was ascribed to various factors: (i) some emulsifiers inhibited lipid digestion and so a fraction of the β-carotene remained inside the undigested droplets and the mixed micelle phase had less solubilization capacity, i.e., lysolecithin, and caseinate; (ii) some emulsifiers protected β-carotene from chemical degradation, i.e., lysolecithin and caseinate; and (iii) some emulsifiers promoted sedimentation of the β-carotene-loaded micelles, i.e., lysolecithin. These results suggest that food emulsion behavior in the human gut may be influenced by the nature of the emulsifier employed, which is important knowledge when creating functional food and beverage products.
Factors impacting lipid digestion and nutraceutical bioaccessibility assessed by standardized gastrointestinal model (INFOGEST): oil.
Tan Yunbing,Zhang Zhiyun,Liu Jinning,Xiao Hang,McClements David Julian
Food & function
The oil droplets in commercial emulsified foods have dimensions that vary widely, from hundreds of nanometers to tens of micrometers. Previously, the size of the droplets in oil-in-water emulsions has been shown to impact their gastrointestinal behavior, which may influence their physiological effects. In this study, we analyzed the impact of oil droplet diameter (0.16, 1.1 and 8.2 μm) on lipid digestion and nutraceutical bioaccessibility using a widely used standardized gastrointestinal tract model: the INFOGEST method. The emulsions used consisted of corn oil droplets stabilized using a food-grade non-ionic surfactant (Tween 20), and the droplet size was controlled by preparing them with a microfluidizer (small), sonicator (medium), or high-shear blender (large). The surfactant-coated oil droplets were relatively resistant to size changes in the mouth and stomach, due to the strong surface activity and steric stabilization mechanism of the non-ionic surfactant used. As expected, the kinetics of lipid digestion were enhanced for smaller droplets because of their greater specific surface area. The degree of lipid digestion fell from 117% to 78% (p < 0.001) as the initial droplet diameter was raised from 0.16 to 8.2 μm. In addition, there was a reduction in β-carotene bioaccessibility from 83 to 15% (p < 0.001) with increasing droplet diameter. This result was ascribed to several effects: (i) some carotenoids were trapped inside the undigested oil phase; (ii) fewer mixed micelles were produced to internalize the carotenoids; and, (iii) a fraction of the carotenoids crystallized and sedimented. Our results underline the critical importance of considering droplet size when developing emulsified foods loaded with carotenoids. The results obtained by the INFOGEST method are consistent with those found using other in vitro methods in earlier studies.
Impact of calcium levels on lipid digestion and nutraceutical bioaccessibility in nanoemulsion delivery systems studied using standardized INFOGEST digestion protocol.
Tan Yunbing,Li Ruyi,Zhou Hualu,Liu Jinning,Muriel Mundo Jorge,Zhang Ruojie,McClements David Julian
Food & function
Recently, the standardized in vitro digestion model ("INFOGEST method") used to evaluate the gastrointestinal fate of foods has been revised and updated (Brodkorb et al., 2019, Nat. Protoc., 2019, 14, 991-1014). Under fed state conditions, the calcium level used in this model is fixed and relatively low: 0.525 mM. In practice, the calcium concentration in the human gut depends on the nature of the food consumed and may vary from person-to-person. For this reason, we examined the impact of calcium concentration on the gastrointestinal fate of a model nutraceutical delivery system. The effect of calcium level (0.525-10 mM) on lipid digestion and β-carotene bioaccessibility in corn oil-in-water nanoemulsion was investigated using the INFOGEST method. At all calcium levels, the lipids were fully digested, but this could only be established by carrying out a back titration (to pH 9) at the end of the small intestine phase. Conversely, the bioaccessibility of β-carotene decreased with increasing calcium levels: from 65.5% at 0.525 mM Ca2+ to 23.7% at 10 mM Ca2+. This effect was attributed to the ability of the calcium ions to precipitate the β-carotene-loaded mixed micelles by forming insoluble calcium soaps. The ability of calcium ions to reduce carotenoid bioaccessibility may have important nutritional implications. Our results show that the bioaccessibility of hydrophobic carotenoids measured using the INFOGEST method is highly dependent on the calcium levels employed, which may have important consequences for certain calcium-rich foods. Moreover, we have shown the importance of carrying out a back titration to accurately measure free fatty acid levels in the presence of low calcium levels.
The impact of galactooligosaccharides on the bioaccessibility of sterols in a plant sterol-enriched beverage: adaptation of the harmonized INFOGEST digestion method.
Blanco-Morales Virginia,López-García Gabriel,Cilla Antonio,Garcia-Llatas Guadalupe,Barberá Reyes,Lagarda María Jesús,Sánchez-Siles Luis Manuel,Alegría Amparo
Food & function
The effect of the addition of galactooligosaccharides (GOS) on sterol bioaccessibility in three plant sterol (PS)-enriched milk-based fruit beverages (without GOS addition (MfB) and with 2.5 g (MfB-G2) and 5.0 g (MfB-G5) GOS per 250 mL) was evaluated after micellar gastrointestinal digestion. Cholesterol bioaccessibility was very similar among beverages, though a slight significant increase (from 80% to 85%) was observed by the addition of 5.0 g GOS. The addition of GOS did not affect total PS bioaccessibility (≈37%). Based on the results obtained after micellar digestion, it has been demonstrated that these beverages could be a suitable food matrix for simultaneous enrichment with PS and GOS. The harmonized in vitro digestion model INFOGEST was applied to the MfB beverage, but the cholesterol content could not be quantified due to its contribution of bile salts. Hence, it was proposed: (i) a change in porcine bile salt concentration from 10 mM to 1.4 mM (in order to compare with micellar digestion); or (ii) a change of bile salt origin (bovine instead of porcine), maintaining physiological concentration (10 mM, INFOGEST condition). Both options allowed cholesterol quantification, with bioaccessibilities of 62% (reduction of bile salts) and 38% (replacement of the bile salt source), whereas plant sterol bioaccessibilities were 22% and 14%, respectively. Therefore, the change of bile salt origin maintaining INFOGEST concentration is proposed as a method to evaluate sterol (cholesterol and PS) bioaccessibility in these beverages, demonstrating the need for the selection of appropriate conditions of the INFOGEST harmonized method according to the food matrix and compounds to be determined.
β-lactoglobulin micro- and nanostructures as bioactive compounds vehicle: In vitro studies.
Simões Lívia S,Martins Joana T,Pinheiro Ana C,Vicente António A,Ramos Oscar L
Food research international (Ottawa, Ont.)
β-Lactoglobulin (β-Lg) is known to be capable to bind hydrophilic and hydrophobic bioactive compounds. This research aimed to assess the in vitro performance of β-Lg micro- (diameter ranging from 200 to 300 nm) and nano (diameter < 100 nm) structures associated to hydrophilic and hydrophobic model compounds on Caco-2 cells and under simulated gastrointestinal (GI) conditions. Riboflavin and quercetin were studied as hydrophilic and hydrophobic model compounds, respectively. Cytotoxicity experiment was conducted using in vitro cellular model based on human colon carcinoma Caco-2 cells. Moreover, the digestion process was simulated using the harmonized INFOGEST in vitro digestion model, where samples were taken at each phase of digestion process - oral, gastric and intestinal - and characterized in terms of particle size, polydispersity index (PDI), surface charge by dynamic light scattering (DLS); protein hydrolysis degree by 2,4,6-trinitrobenzene sulfonic acid (TNBSA) assay and native polyacrylamide gel electrophoresis; and bioactive compound concentration. Caco-2 cell viability was not affected up to 21 × 10 mg mL of riboflavin and 16 × 10 mg mL quercetin on β-Lg micro- and nanostructures. In the oral phase, β-Lg structures' particle size, PDI and surface charge values were not changed comparing to the initial β-Lg structures (i.e., before being subjected to in vitro GI digestion). During gastric digestion, β-Lg structures were resistant to proteolytic enzymes and to acid environment of the stomach - confirmed by TNBSA and native gel electrophoresis. In vitro digestion results indicated that β-Lg micro- and nanostructures protected both hydrophilic and hydrophobic compounds from gastric conditions and deliver them to target site (i.e., intestinal phase). In addition, β-Lg structures were capable to enhance riboflavin and quercetin bioaccessibility and bioavailability potential compared to bioactive compounds in their free form. This study indicated that β-Lg micro- and nanostructures were capable to enhance hydrophilic and hydrophobic compounds bioavailability potential and they can be used as oral delivery systems.