Micellar Fraction Research Articles

The Role of Food Matrices Supplemented with Milk Fat Globule Membrane in the Bioaccessibility of Lipid Components and Adaptation of Cellular Lipid Metabolism of Caco-2 Cells.

This study aimed to evaluate the digestive efficiency of food matrices supplemented with milk fat globule membrane isolated from buttermilk (BM-MFGM), using the INFOGEST in vitro digestion protocol hyphenated with the assessment of the digested material on the lipid profile of the Caco-2 cell culture model. First, we examined lipid profiles in food matrices supplemented with BM-MFGM and their subsequent digestion. The results showed distinct lipid profiles in different food matrices and micellar fractions. The presence of BM-MFGM lipids changed the cellular lipid profiles in Caco-2 cell cultures, with diverging contents in cholesteryl esters, triacylglycerides, and neutral lipids depending on the micellar food matrix factor. Hierarchical clustering analysis revealed patterns in cellular lipid responses to micellar stimuli, while volcano plots highlighted significant changes in cellular lipid profiles post-treatment. Thus, this study underscores the importance of in vitro digestion protocols in guiding food matrix selection for bioactive ingredient supplementation, elucidating intestinal epithelium responses to digested food stimuli.

Controlling release of astaxanthin in β-sitosterol oleogel-based emulsions via different self-assembled mechanisms and composition of the oleogelators

In this study, three types of β-sitosterol-based oleogels (β-sitosterol + γ-oryzanol oleogels, β-sitosterol + lecithin, oleogels and β-sitosterol + monostearate oleogels), loaded with astaxanthin, were employed as the oil phase to create oleogel-based emulsions (SO, SL, and SM) using high-pressure homogenization. The microstructure revealed that fine-scale crystals were dispersed within the oil phase of the droplets in the β-sitosterol oleogel-based emulsion. The bioaccessibility of astaxanthin was found to be 58.13 %, 51.24 %, 36.57 %, and 45.72 % for SM, SL, SO, and the control group, respectively. Interestingly, the release of fatty acids was positively correlated with the availability of astaxanthin (P = 0.981). Further analysis of FFAs release and kinetics indicated that the structural strength of the oil-phase in the emulsions influenced the degree and rate of lipolysis. Additionally, the micellar fraction analysis suggested that the nature and composition of the oleogelators in SM and SL also impacted lipolysis and the bioaccessibility of astaxanthin. Furthermore, interfacial binding of lipase and isothermal titration calorimetry (ITC) measurements revealed that the oleogel network within the oil phase of the emulsion acted as a physical barrier, hindering the interaction between lipase and lipid. Overall, β-sitosterol oleogel-based emulsions offer a versatile platform for delivering hydrophobic molecules, enhancing the bioavailability of active compounds, and achieving sustained release.

Novel details on the dissociation of casein micelle suspensions as a function of pH and temperature

Membrane filtration is a widespread process for fractionation and recombination of milk components. Although the dissociation of micellar caseins has been studied in detail in skim milk, it is important to better understand the dissociation dynamics occurring between the colloidal and noncolloidal fractions in systems of modified composition. This research aimed at understanding the dissociation of casein proteins in micellar fractions depleted of whey proteins. Casein micelle dispersions were tested at neutral pH and pH 6 (using glucono-δ-lactone as acidulant), after incubation at 4°C or 22°C, and compared with skim milk. The ionic composition of the serum phase was measured using inductively coupled plasma-mass spectrometry, and the protein distribution analyzed using reversed phase-HPLC coupled with mass spectrometry. When incubated at 22°C, there were no differences in casein micelle dissociation between skim milk and whey protein-depleted micelles (∼2.6% dissociated casein). No additional dissociation occurred by lowering the pH from 6.8 to 6 at 22°C, albeit there were more soluble ions at low pH (71% Ca and 65% P). At 4°C, there was an increased amount of β-casein found in the serum phase (23-33% of total β-casein). In addition, there was an uneven dissociation behavior of the various genetic β-casein variants, whereof A2 was more readily released with cooling. In skim milk, approximately 22%, 18%, and 14% of κ-, αS2, and αS1-caseins, respectively, were dissociated from the micellar phase upon cooling and acidification to pH 6.0. This was in contrast to whey protein-depleted casein suspensions, in which only 6%, 5%, and 3% of κ-, αS2, and αS1-caseins, respectively, had dissociated. The results suggested that the whey proteins in the serum phase play a role in the equilibrium between colloidal and soluble caseins in milk. This is of great relevance in processes such as cold membrane fractionation, where more attention should be given to the protein composition in the serum phase, especially when concentration is combined with fractionation of the serum proteins.

Food matrix impacts bioaccessibility and assimilation of acid whey-derived milk fat globule membrane lipids in Caco-2 cells.

The milk fat globule membrane (MFGM) imparts human health benefits ranging from improved immune system, gut, and brain function to improved cardiometabolic health. The industry's growing interest in introducing MFGM-enriched foods requires scientific evidence that the benefits derived from this compound are not affected by the formulation or processes that may alter its function, such as the digestion process. In this study, the impact of food matrices and supplementation levels on the bioaccessibility and assimilation of MFGM lipids in cell culture was investigated. Three food matrices including a protein-rich jelly, carbohydrate-rich cookie, and a carbohydrate- and fat-rich cookie with sunflower oil (SF-cookie) were supplemented with an MFGM ingredient derived from cottage cheese acid whey at 2, 5, and 10% (w/w). Each formulation underwent simulated digestion consisting of oral, gastric, and intestinal phases, and the micellar fraction was collected for both analysis and lipid assimilation in Caco-2 intestinal cells. The micellar fractions were diluted and applied to the cells for 4 h. A lipidomic approach was used to assess the lipid profiles of micellar fractions and intestinal cells. The micelles from digested jellies, cookies, and SF-cookies containing MFGM showed a distinct separation using partial least squares discriminant analysis (PLS-DA). Both correlation loadings and variable importance in projection (VIP) scores demonstrated a tendency of MFGM polar lipids (ceramides, glucosylceramides) for micelles from digested jelly, whereas micelles from digested cookies were associated with MFGM neutral lipids (free fatty acids, cholesterol, etc.). The effect of supplementation level on the micellar lipid profiles reinforced this pattern. The lipid profiles of intestinal cells after incubation with the micellar fractions differed considerably from the corresponding micellar lipid profiles. Specifically, the SF-cookie-treated cells were associated with a greater abundance of PUFA relative to jelly- and cookie-treated cells; however, increasing MFGM supplementation showed irregular patterns and rearrangement of cellular lipid profiles, suggesting the cells' role in regulating lipid metabolism in response to nutritional stimuli. The nature of lipid micellarization and assimilation in intestinal cells from MFGM-containing food formulations echoes the complexity of lipids inherent to the MFGM itself, suggesting the need for application-based MFGM supplementation.

In vitro bioaccessibility evaluation of chlorophyll pigments in single and binary carriers

Chlorophyll was extracted and microencapsulated using different carrier agents. Subsequently, in vitro digestion was performed, and the bioaccessibility of chlorophyll in the different encapsulation systems was carried out. The zeta potential, particle size, and PDI were significantly modified after the micellarization of digested microcapsules. I-W-Chl presented with the highest total chlorophyll recovery and micellarization rate of 54% and 43%, respectively. In the aqueous micellar fraction, the different encapsulation systems had total chlorophylls, pheophytins, and pheophorbides ranging from 13 to 49%, 42 – 77%, and 3 – 22% respectively. The bioaccessibility of total chlorophyll pigment ranging from 7% to 20% is given in the following order: I-W-Chl > WPI-Chl > Z-Chl > Ca-Chl > SCChlV > SCChlC. The result established in this study shows that the carrier agent type could inhibit or mediate the bioaccessibility of chlorophyll with the potential to be an efficient delivery system for health promoting compounds.

An ex vivo intestinal absorption model is more effective than an in vitro cell model to characterise absorption of dietary carotenoids following simulated gastrointestinal digestion

To get the most accurate food digestion-related data, and how this affects nutrient absorption, it is critical to carefully simulate human digestion systems using model settings. In this study, the uptake and transepithelial transportation of dietary carotenoids was compared using two different models that have previously been used to assess nutrient availability. The permeability of differentiated Caco-2 cells and murine intestinal tissue were tested using all-trans-β-carotene and lutein prepared in artificial mixed micelles and micellar fraction from orange-fleshed sweet potato (OFSP) gastrointestinal digestion. Transepithelial transport and absorption efficiency were then determined using liquid chromatography tandem-mass spectrometry (LCMS-MS). Results showed that the mean uptake for all-trans-β-carotene in the mouse mucosal tissue was 60.2 ± 3.2% compared to 36.7 ± 2.6% in the Caco-2 cells with the mixed micelles as the test sample. Similarly, the mean uptake was higher in OFSP with 49.4 ± 4.1% following mouse tissue uptake compared to 28.9 ± 4.3% using Caco-2 cells for the same concentration. In relation to the uptake efficiency, the mean percentage uptake for all-trans-β-carotene from artificial mixed micelles was 1.8-fold greater in mouse tissue compared to Caco-2 cells (35.4 ± 1.8% against 19.9 ± 2.6%). Carotenoid uptake reached saturation at 5 µM when assessed with the mouse intestinal cells. These results demonstrate the practicality of employing physiologically relevant models simulating human intestinal absorption processes that compares well with published human in vivo data. When used in combination with the Infogest digestion model, the Ussing chamber model, using murine intestinal tissue, may thus be an efficient predictor of carotenoid bioavailability in simulating human postprandial absorption ex vivo.

Magnetic beads for the evaluation of drug release from biotinylated polymeric micelles in biological media.

To improve the reliability of in vitro release studies of drug delivery systems, we developed a novel in vitro method for the evaluation of drug release from polymeric micelles in complex biological media. Polymeric micelles based on poly(N-2-hydroxypropyl methacrylamide)-block-poly(N-2-benzoyloxypropyl methacrylamide) (p(HPMAm)-b-p(HPMAm-Bz)) of which 10% of the chains was functionalized with biotin at the p(HPMAm) terminus were prepared using a solvent extraction method. The size of the micelles when loaded with a hydrophobic agent, namely paclitaxel (a clinically used cytostatic drug) or curcumin (a compound with multiple pharmacological activities), was around 65nm. The biotin decoration allowed the binding of the micelles to streptavidin-coated magnetic beads which occurred within 10min and reached a binding efficiency of 90±6%. Drug release in different media was studied after the magnetic separation of micelles bound to the streptavidin-coated beads, by determination of the released drug in the media as well as the retained drug in the micellar fraction bound to the beads. The in vitro release of paclitaxel and curcumin at 37°C in PBS, PBS containing 2% v/v Tween 80, PBS containing 4.5% w/v bovine serum albumin, mouse plasma, and whole mouse blood was highly medium-dependent. In all media studied, paclitaxel showed superior micellar retention compared to curcumin. Importantly, the presence of serum proteins accelerated the release of both paclitaxel and curcumin. The results presented in this study show great potential for predicting drug release from nanomedicines in biological media which in turn is crucial for their further pharmaceutical development.

The Influence of Increasing Lecithin Concentrations on Carotenoid Bioaccessibility and Cell Uptake

ObjectivesWe sought to determine if lecithin would produce a dose-response effect, increasing carotenoid bioaccessibility and Caco-2 cell uptake. MethodsA mixture of β-carotene, lycopene, lutein and zeaxanthin was digested with increasing concentrations of lecithin (0–10 mg lecithin/mL test meal) and ∼4% vegetable oil (n = 6 per condition). In vitro gastric, duodenal, and jejunal digestion was mimicked for 1 h each, and the micellar fraction isolated for analysis. Additionally, Caco-2 cells producing a monolayer reflecting a small intestinal phenotype were incubated with of the micellular fraction for 4 h, and cells harvested for extraction. The micellular fraction and cell were extracted with hexane and dichloromethane, and the organic phase dried under argon. Micellular carotenoids were quantitated using high performance liquid chromatography-diode-array detection (HPLC-DAD), while cellular carotenoids were quantitated using UHPLC-tandem mass spectrometry (UHPLC-MS/MS). One-way ANOVA followed by Tukey’s post-hoc test was used to assess statistically significant differences between lecithin doses on carotenoid bioaccessibility and cellular uptake. Fractions of digesta were also visualized using confocal microscopy, to better elucidate the lecithin-micelle interaction. ResultsLecithin significantly increased β-carotene and zeaxanthin bioaccessibility only when comparing the most extreme doses tested. No significant differences were observed for lycopene or lutein bioaccessibility. Likewise, lecithin did not produce a significant increase in the cell uptake in the range tested. ConclusionsOverall, lecithin had minimal impact on carotenoid bioaccessibility, and Caco-2 cell uptake of carotenoids. Funding SourcesThis work was supported by a research grant from Nu Skin Enterprises, Inc.

Insights on the Bioaccessibility of Natural Pigments from Diatom Chaetoceros calcitrans.

This study aimed to investigate the bioaccessibility of carotenoids and chlorophylls from the biomass of microalgae Chaetoceros calcitrans. The samples were submitted to an in vitro digestion protocol, and the compounds were determined by HPLC-PDA-MS/MS. A total of 13 compounds were identified in all tests. After in vitro digestion, the relative bioaccessibility of carotenoids and chlorophylls ranged from 4 to 58%. The qualitative profile of carotenoids reflected the initial sample, with all-E-zeaxanthin (57.2%) being the most bioaccessible compound, followed by all-E-neochrome (31.26%), the latter being reported for the first time in the micellar fraction. On the other hand, among the chlorophylls only pheophytin a (15.01%) was bioaccessible. Furthermore, a chlorophyll derivative (Hydroxypheophytin a’) was formed after in vitro digestion. Considering all compounds, xanthophylls (12.03%) and chlorophylls (12.22%) were significantly (p < 0.05) more bioaccessible than carotenes (11.22%). Finally, the considerable individual bioaccessibilities found, especially for zeaxanthin, demonstrate the bioactive potential of this bioresource. However, the large reduction in the totality of compounds after in vitro digestion suggests that additional technological strategies should be explored in the future to increase the efficiency of micellarization and enhance its bioactive effects.

Temperature-dependent dissociation of human micellar β-casein: Implications of its phosphorylation degrees and casein micelle structures

Temperature-dependent dissociation of human micellar β-casein regarding its phosphorylation degrees and micelle structures were studied. Human milk was fractionated at 25 °C into soluble (S-25 °C) and micellar (M-25 °C) fractions, and the latter was fractionated at 4 °C into soluble (S-4 °C) and micellar (M-4 °C) fractions. β-casein ratios among S-25 °C, S-4 °C and M-4 °C were 19%, 59% and 22%. β-casein isoforms were predominated by 0-P, 1-P and 2-P in S-25 °C, by 0-P, 1-P, 2-P and 4-P in S-4 °C, and by 0-P in M-4 °C. For micelles remained after dissociation of β-casein and calcium, the size increased, molar mass decreased, morphologies were maintained, and internal protein inhomogeneities disappeared, compared with micelles in M-25 °C. β-casein isoforms with lower phosphorylation degrees may form a frame mainly through hydrophobic interactions, attached with more highly phosphorylated isoforms and colloidal calcium phosphate via calcium bridges for forming human micelle.

Turmeric, red pepper, and black pepper affect carotenoids solubilized micelles properties and bioaccessibility: Capsaicin/piperine improves and curcumin inhibits carotenoids uptake and transport in Caco-2 cells.

This study aimed to evaluate the role of spices/spice active principles on physical, biochemical, and molecular targets of bioaccessibility/bioavailability. Carotenoids-rich micellar fraction obtained through simulated digestion of green leafy vegetables (GLV) with individual or two/three combinations were correlated to their influence on bioaccessibility, cellular uptake, and basolateral secretion of carotenoids in Caco-2 cells. Results suggest that carotenoids' bioaccessibility depends on micelles physicochemical properties, which is affected due to the presence of co-treated dietary spices and their composition. Increased bioaccessibility of β-carotene (BC) and lutein (LUT) is found in GLV (spinach) digested with turmeric (TM) than red pepper (RP) and black pepper (BP). In contrast, enhanced cellular uptake and secretion of BC and LUT-rich triglyceride-rich lipoprotein is observed in the presence of RP and BP compared to the control group. In contrast, TM inhibited absorption, while retinol levels significantly reduced in the presence of TM and RP than BP. Control cells have indicated higher cleavage of β-carotene to retinol than the spice-treated group. Besides, spice active principles modulate facilitated transport of carotenoids by scavenger receptor class B type 1 (SR-B1) protein. The effect of spices on carotenoids' bioavailability is validated with active spice principles. Overall, carotenoids' bioavailability (cellular uptake and basolateral secretion) was found in the following order of treatments; piperine>capsaicin>piperine + capsaicin>curcumin + capsaicin + piperine>control>turmeric. These findings suggested that the interaction of specific dietary factors, including spice ingredients at the enterocyte level, could provide greater insight into carotenoid absorption. PRACTICAL APPLICATION: Spices/spice active principles play a role in the digestion process by stimulating digestive enzymes and bile acids secretion. Since carotenoids are lipid soluble and have low bioavailability, spice ingredients' influence on intestinal absorption of carotenoids is considered crucial. Hence, understanding the interaction of co-consumed spices on the absorption process of carotenoids may help to develop functional foods/formulation of nutraceuticals to improve their health benefits.

Spice active ingredients affect the micellization, permeation and bioavailability of structurally different carotenoids in human intestinal epithelial Caco-2 cells.

AbstractThis study evaluated the influence of active spice ingredients on the bioaccessibility and bioavailability of different carotenoids at the enterocyte level. Briefly, carotenoids solubilized micellar fractions obtain by simulated digestion of spinach (β-carotene; BC and lutein; LUT) or brown seaweed (fucoxanthin; FUCO) or shrimp (astaxanthin; AST) either with or without curcumin/capsaicin/piperine. Further, physicochemical properties (particle size and viscosity) of micelles were analyzed and correlated bioaccessibility, permeability characteristics, and bioavailability of carotenoids in Caco-2 cells. The digestion of carotenoid's source with spice compound affected carotenoid solubilization/micellization, cumulative percent of particle size, and viscosity in the following order of spice compound treatments; curcumin &gt; capsaicin &gt; piperine &gt; control. The carotenoids level in micelles higher in capsaicin and piperine than curcumin and control digested groups. The increased carotenoids bioaccessibility may be due to lesser hydrophobic interaction found in capsaicin and piperine than curcumin. Further, based on importance and distinct nature, BC and LUT were used bioavailability studies. The enhanced cellular uptake and secretion of carotenoids in triglycerides rich lipoproteins by capsaicin and piperine is due to changes in integrity, permeability, the fluidity of the epithelial barrier of absorption than curcumin and control groups. These findings opine the interaction of carotenoids with specific dietary component (spices) and their regulatory metabolism at the intestinal level is vital for the enteral nutrition of carotenoids.

Distribution and variation in proteins of casein micellar fractions response to heat-treatment from five dairy species

Casein micelles (CMs) contribute to the physicochemical properties and stability of milk. However, how the proteome of CMs changes following heat treatment has not been elucidated. Here, changes in the proteins of CMs in samples of Holstein, buffalo, yak, goat, and camel milk following heat treatment were investigated using a LC-MS/MS approach. According to the hierarchical clustering results, Holstein, yak, and buffalo milk samples had similar CMs protein components, followed by goat and camel milk samples. Changes in lipoprotein lipase and α-lactalbumin in CMs were dependent on the intensity of heat treatment and were similar among the studied species, whereas changes in κ-casein, lactoferrin, and apolipoprotein A-I differed among different types of milk. These results provide information on the distribution and variations of the proteomes of CMs following heat treatment, which will assist in the identification of proteins that are dissociated and attached to CMs from different dairy species during heat treatment.

An Integrative Approach of an In Vitro Measurement of the Digestibility of Triacylglycerols of Human Milk.

Several studies have been published regarding the effect of different factors on the digestion of milk lipids, considering their natural structural arrangement as milk fat globules and the efficiency of the digestive enzymes in the lipolysis of such complex structures. During digestion, the lipolytic products are dispersed in vesicles and micelles, which are the source for absorption of digested lipids. Therefore, it is necessary to consider the isolation of the micellar phase from the digesta to appropriately determine the amounts and classes of lipids which are bioaccessible. This study presents an integrative approach that included an isolation procedure to separate the micellar fraction from undigested and non-micellar parts, and the distribution of digested milk lipids in micelles determined directly through chromatographic techniques. Four groups of five full term mothers donated colostrum or mature milk. Two sets of samples were analyzed directly (raw), and two sets were pasteurized and then analyzed. Our data revealed that the profile of digested milk lipids is different depending on the lactation period and processing stage, while the carbon atom number distribution of the digested triacylglycerols in the micellar fraction provides a substantial information regarding the acylglycerols species that are less available for absorption.

Effect of Core-Crosslinking on Protein Corona Formation on Polymeric Micelles.

Most nanomaterials acquire a protein corona upon contact with biological fluids. The magnitude of this effect is strongly dependent both on surface and structure of the nanoparticle. To define the contribution of the internal nanoparticle structure, protein corona formation of block copolymer micelles with poly(N-2-hydroxypropylmethacrylamide) (pHPMA) as hydrophilic shell, which are crosslinked-or not-in the hydrophobic core is comparatively analyzed. Both types of micelles are incubated with human blood plasma and separated by asymmetrical flow field-flow fractionation (AF4). Their size is determined by dynamic light scattering and proteins within the micellar fraction are characterized by gel electrophoresis and quantified by liquid chromatography-high-resolution mass spectrometry-based label-free quantitative proteomics. The analyses reveal only very low amounts of plasma proteins associated with the micelles. Notably, no significant enrichment of plasma proteins is detectable for core-crosslinked micelles, while noncrosslinked micelles show a significant enrichment of plasma proteins, indicative of protein corona formation. The results indicate that preventing the reorganization of micelles (equilibrium with unimers) by core-crosslinking is crucial to reduce the interaction with plasma proteins.

Delivery of β-carotene to the in vitro intestinal barrier using nanoemulsions with lecithin or sodium caseinate as emulsifiers

To increase the intestinal delivery of dietary β-carotene, there is a need to develop nanostructured food systems to encapsulate this fat soluble bioactive. The aim of this study was to evaluate the bioacessibility and bioavailability across the intestinal barrier of β-carotene-enriched nanoemulsions stabilised with two emulsifiers (lecithin or sodium caseinate) by coupling an in vitro gastrointestinal digestion with two in vitro cell culture models (Caco-2 or co-culture of Caco-2/HT29-MTX). Nanoemulsions stabilised with lecithin had significantly higher β-carotene in the gastrointestinal digested micellar fraction, lower β-carotene in the Caco-2 (and Caco-2/HT29-MTX) apical compartment and significantly higher β-carotene in Caco-2 cellular content compared to β-carotene-enriched nanoemulsions stabilised with sodium caseinate. Finally, to assess anti-inflammatory activity of digested nanoemulsions, lipopolysaccharide stimulated macrophages were exposed to Caco- 2 basolateral samples with levels of TNF-α and IL-β, subsequently quantified. A TNF-α response from stimulated THP-1 macrophages was elicited by basolateral samples, regardless the emulsifier used to formulate nanoemulsions. This study demonstrated that β-carotene permeability is influenced by the food derived emulsifier used for stabilising nanoemulsions, indicating that composition may be a critical factor for β-carotene delivery.

Characterization of Processing Influences on In Vitro Bioaccessibility of Carotenoids and Chlorophylls from Six Spinach Genotypes

Abstract Objectives Spinach is a rich source of bioactives including carotenoids and chlorophylls. Ultimate delivery, or bioavailability, of these bioactives to consumers varies depending on pre-/post-harvest factors that impact the food matrix. The interaction between food processing, oral processing (mastication), and spinach genotype have not been explored. Insights into these factors hold the potential to identify interaction effects between genotype and processing (GxP). Methods Six genotypes of spinach selected based on previous bioaccessibility screening were greenhouse grown in Salisbury, NC (Fall 2019), harvested, and stored fresh at 4C (24 hr) or at −80C after processing by blanching (2 min, 100C), thermal sterilization (121C for 15 min), or juicing. All genotypes were subjected to all processing methods, and a portion of each sample was subjected to simulated mastication while another was homogenized (30 sec) into a puree. All samples were subjected to a three-phase in vitro digestion to assess the transfer of carotenoids and chlorophyll derivatives from the food matrix to the aqueous micellar fraction (bioaccessibility). Results Processing method, genotype, and GxP had a significant influence on total bioactive content (P &amp;lt; 0.01), relative bioaccessibility (P &amp;lt; 0.01), and bioaccessible content (P &amp;lt; 0.01). Average bioactive content decreased in the order of juiced (26.2–36.9 μmol/g), blanched (23.3–30.0 μmol/g), thermally sterilized (22.5–27.3 μmol/g), and fresh spinach (18.6–25.0 μmol/g). Bioaccessible content decreased from juiced (6.8–9.8 μmol/g), to fresh (4.0–6.9 μmol/g) and blanched (4.6–5.6 μmol/g), and then thermally sterilized (2.4–3.3 μmol/g). Bioaccessible content from masticated samples was similar for thermally sterilized (0.9–1.5 μmol/g) and fresh samples (0.7–1.3 μmol/g). Conclusions Results indicate that heat treatment preserves bioactives in these six spinach genotypes and may modestly decrease their bioaccessibility. Influence of mastication on bioaccessible content of bioactives supports the notion that oral processing is a critical factor impacting ultimate bioaccessibility from vegetables. Together, these results provide valuable information for optimization of bioactive delivery. Funding Sources Foundation for Food and Agriculture Research.

High-pressure homogenization as compared to pasteurization as a sustainable approach to obtain mandarin juices with improved bioaccessibility of carotenoids and flavonoids

High-pressure technologies are among those with increased interest in the sustainable production of quality-enhanced food products. In this work, Ortanique mandarin juices have been submitted to traditional pasteurization conditions (time/temperature of 65 °C/15 s, 85 °C/15 s and 92 °C/30 s) and energy-saving high-pressure homogenization (HPH, 150 MPa) treatments to compare the effects on the physicochemical composition and in vitro bioaccessibility of carotenoids and flavonoids. In general, physicochemical attributes of the homogenized sample were similar to those found in fresh juice, with similar ascorbic acid content and cloudiness but with significant colour differences in all cases. The bioaccessibility of total carotenoids was similar in fresh and pasteurized juices in contrast to the HPH sample that exhibited a five-fold increase, which suggests a positive effect of particle size reduction to favour the action of digestive enzymes. A clear increase in the levels of epoxycarotenoids was detected in the micellar fractions of digested HPH juices, although such carotenoids are not detected in human fluids or tissues. Regarding the bioaccessibility of flavonoids, no significant differences were found in the samples studied. Results obtained can help the implementation of HPH processing to obtain natural beverages with enhanced nutritional properties.

Thermal disruption of the food matrix of biofortified lettuce varieties modifies absorption of carotenoids by Caco-2 cells

Amongst green leafy vegetables, new varieties of lettuce enriched in lutein and β-carotene are being developed to provide increased supply of dietary carotenoids. We investigated the effect of lettuce genotypes (varieties) and thermal treatments on lutein and β-carotene bioaccessibility to the micellar fraction (and also carotenoid bioavailability) using a human Caco-2 cell model system. Carotenoid absorption by mammalian cells is not correlated with initial carotenoid concentration in fresh lettuce leaves. While thermal treatment of lettuce leaves increases carotenoid availability, resulting in higher lutein and β-carotene absorption, disruption of the food matrix by prior cooking results in reduced carotenoid levels and transfer to the micellar fraction. Unless the food matrix is disrupted through breeding or post-harvest treatments, absorption of carotenoids from biofortified lettuce remains similar to lettuce cultivars with low carotenoid levels. Genetic improvement programs for biofortified lettuce varieties need to focus on increasing the carotenoid bioavailability from the food matrix.

Development of Infrared Prediction Models for Diffusible and Micellar Minerals in Bovine Milk.

Simple SummaryMinerals are distributed in milk in two main forms: The diffusible (or soluble) fraction, composed of free ions and inorganic salts, and the micellar fraction, composed of mineral elements located on the surface or in the inner part of casein micelles. The ratio between diffusible and micellar minerals strongly affects milk coagulation ability. The objective of this study was to investigate the ability of mid-infrared spectroscopy to predict diffusible and micellar Ca, P, K, Mg and Na in individual milk samples of Holstein Friesian cows. Overall, the accuracy of mid-infrared prediction models was moderate for Ca, P and Mg, and low for micellar K, micellar Na and diffusible Na.Milk and dairy products are major sources of minerals in human diet. Minerals influence milk technological properties; in particular, micellar and diffusible minerals differentially influence rennet clotting time, curd firmness and curd formation rate. The aim of the present study was to investigate the ability of mid-infrared spectroscopy to predict the content of micellar and diffusible mineral fractions in bovine milk. Spectra of reference milk samples (n = 93) were collected using Milkoscan™ 7 (Foss Electric A/S, Hillerød, Denmark) and total, diffusible and micellar content of minerals were quantified using inductively coupled plasma optical emission spectrometry. Backward interval partial least squares algorithm was applied to exclude uninformative spectral regions and build prediction models for total, diffusible and micellar minerals content. Results showed that backward interval partial least squares analysis improved the predictive ability of the models for the studied traits compared with traditional partial least squares approach. Overall, the predictive ability of mid-infrared prediction models was moderate to low, with a ratio of performance to deviation in cross-validation that ranged from 1.15 for micellar K to 2.73 for total P.