Influence of thermal denaturation on whey protein isolates in combination with chitosan for fabricating Pickering emulsions: a comparison study

Composite natural emulsifiers such as whey protein isolate (WPI) and chitosan (CS) are commonly used in Pickering emulsions to address the effect of thermal deformation of proteins before complexation with CS and heating after complexation. In this study, the properties of WPI and CS composites were investigated by complexing CS with either unmodified WPI or thermally denatured WPI (DWPI). Three types of composite particles were prepared, WPI-CS, DWPI-CS, and D(WPI-CS). Atomic force microscopy revealed that the composite particles formed larger aggregates with increased contour size and surface roughness compared to CS and WPI, whereas the interfacial tension decreased, indicating improved emulsifying abilities. Fourier-transform infrared analysis revealed differences in the hydrogen bonds between CS and WPI/DWPI. All three composite particles formed stable emulsions with droplet sizes of 20.00 ± 0.15, 27.80 ± 0.35, and 16.77 ± 0.51 μm, respectively. Thermal stability experiments revealed that the curcumin emulsion stabilized with WPI-CS and DWPI-CS exhibited relatively better thermal stability than that stabilized with D(WPI-CS). In vitro experiments results indicated that the bioaccessibility of the curcumin emulsion stabilized with WPI-CS was 61.18 ± 0.16%, significantly higher than that of the emulsions prepared with the other two composite particles (p < 0.05). This study will enable the customized design of WPI composite-based Pickering emulsions for application in the food and nutrition industries.

Influence of different electrolytes and oils on the stability of W1/O/W2 double emulsion during storage and in vitro digestion

The aim of this study is to formulate a stable water-in-oil-in-water (W1/O/W2) double emulsion using different types of oils and electrolytes. W1/O was formulated with different electrolyte solutions (W1) dispersed in various oils (O) using polyglycerol polyricinoleate as a stabilizer. External aqueous phase was Tween-80 (W2), and W1/O dispersed in W2 was used. The emulsion containing NaCl or MgCl2 exhibited high encapsulation efficiency (EE) and maintained particle size. Regarding the oil type, the emulsion with MCT oil showed a small droplet size and a high viscosity and EE, presenting a stable droplet distribution in optical observation. The stability of emulsion containing NaCl was maintained during the in vitro digestion experiments. MCT oil, NaCl and MgCl2 have the potential to produce stable double emulsions for storage stability and in vitro digestion studies. The findings would be useful for preparing stable double emulsions used in the food and cosmetic industries.

Improvement in the Stability and Bioaccessibility of Carotenoid and Carotenoid Esters from a Papaya By-Product Using O/W Emulsions

The aim of the present work was to improve the stability and bioaccessibility of carotenoids from green oil extracts obtained from papaya by-products using oil-in-water (O/W) emulsions. The effects of different concentrations of pectin (1%, 2%, and 3%), a high-molecular-size emulsifier, together with Tween 20, a low-molecular-size emulsifier, high-speed homogenization conditions (time: 2, 3, 4, and 5 min; rpm: 9500, 12,000, 14,000, and 16,000 rpm), and high-pressure homogenization (HPH) (100 MPa for five cycles) were evaluated to determine the optimal conditions for obtaining O/W stable emulsions with encapsulated carotenoids. Soybean, sunflower, and coconut oils were used to formulate these O/W emulsions. The bioaccessibility of the main individual encapsulated papaya carotenoids was evaluated using the INFOGEST digestion methodology. In addition, the microstructures (confocal and optical microscopy) of the O/W carotenoid emulsions and their behavior during in vitro digestion phases were studied. Sunflower O/W carotenoid emulsions showed smaller mean particle size, higher negative ζ-potential, and higher viscosity than soybean O/W emulsions. Particle size reduction in the O/W emulsions using the HPH process improved the bioaccessibility of papaya encapsulated carotenoids. In these O/W emulsions, depending on the vegetable oil, lycopene was the carotenoid with the highest bioaccessibility (71-64%), followed by (all-E)-β-carotene (18%), (all-E)-β-cryptoxanthin (15%), and (all-E)-β-cryptoxanthin laurate (7-4%). These results highlight the potential of using green carotenoid papaya extracts to formulate O/W emulsions to enhance carotenoid bioactivity by efficiently preventing degradation and increasing in vitro bioaccessibility.

Use of excipient emulsions for improving the bioaccessibility of antioxidants in tomato sauce

In this study, tomato sauces were prepared by adding different levels of emulsified oil (0, 5, 10, or 20 wt%) to tomato pomace. The effects of adding these excipient emulsions on the concentration, bioaccessibility, and bioactivity of the carotenoids and phenolics in the tomato sauces were then determined. The carotenoid and phenolic profiles were analyzed by HPLC and LC-MS/MS, respectively. The bioaccessibility values of the lycopene, lutein, and β-carotene were around 36-82%, 73-112%, and 67-94% for tomato sauces with excipient emulsions, respectively. In contrast, they were considerably lower for tomato sauces without excipient emulsions, being around 24-31%, 69-71%, and 45-62%, respectively. The TPC and TAC values of the tomato sauces with the excipient emulsions were significantly higher than those without. Considerably higher concentrations of carotenoids and phenolic compounds were detected in the tomato sauce samples containing the excipient emulsions. These results suggest that the presence of the oil droplets increased the extractability, stability, and bioaccessibility of the nutraceuticals in the tomato sauce.

Emulsifying properties, in vitro digestive characteristics, and β-carotene bioaccessibility of mandarin peel pectin emulsions prepared with different carrier oil phases

Mandarin peel pectin (MPP) emulsions were prepared with different oil phase loadings with or without β-carotene, and their emulsifying characteristics, digestive properties and β-carotene bioaccessibility were investigated. Results revealed that all MPP emulsions exhibited good loading efficiency for β-carotene, while their apparent viscosity and interfacial pressure (π) of MPP emulsions increased significantly after the addition of β-carotene. Emulsification of MPP emulsions as well as digestibility were significantly dependent on the kind of oil. MPP emulsions prepared with long-chain triglycerides (LCT) oil (soybean, corn, and olive oil) exhibited higher volume average particle size (D_4,3), apparent viscosity, π values, and bioaccessibility of carotene compared to those prepared with medium-chain oils (MCT). MPP emulsions with LCT rich in monosaturated fatty acids (olive oil) had the highest β-carotene encapsulation efficiency, bioaccessibility, etc. than from other oils. This study provides a theoretical basis for the efficient encapsulation and high bioaccessibility of carotenoids with pectin emulsions.

Effects of dietary fat type and emulsification on carotenoid absorption: a randomized crossover trial

BACKGROUND

Although emerging evidence has suggested that the type and emulsification of dietary fat may be important to carotenoids absorption, these effects have not yet been validated in a human trial.

OBJECTIVE

This study aimed to examine the effects of dietary fat type and emulsification on the bioaccessibility and bioavailability of carotenoids from a carotenoids-rich salad.

METHODS

An identical salad was used for the in vitro and the human trial. This was paired with 28 g of one of the following four different fats: i) non-emulsified olive oil; ii) emulsified olive oil; (iv) non-emulsified coconut oil; v) emulsified coconut oil. The bioaccessibility of total carotenoids (TC) was assessed by a simulated in vitro digestion model. Sixteen subjects consumed salad with four test fats in random order, and plasma triglyceride and carotenoid (lutein, zeaxanthin, α-carotene, β-carotene, and lycopene) concentrations were determined hourly for 10 hours following the consumption. The absorption of TC and individual carotenoids were evaluated by the positive incremental area under the curve (iAUC) of plasma carotenoid concentrations.

RESULTS

The bioaccessibility of TC was greater with olive oil (24.0%) than with coconut oil (14.9%), and with the oil being emulsified (23.5%) rather than non-emulsified (15.4%). Likewise, the positive iAUC_1-10h of TC, α-carotene and lycopene were 55.2%, 110.8% and 45.8%, respectively, higher with olive oil than with coconut oil. Emulsified fat induced 40.0% greater positive iAUC_1-10h of TC than non-emulsified fat.

CONCLUSIONS

The type and emulsification of dietary fat are both essential to the carotenoid absorption. Findings from this study may provide scientific support for designing excipient emulsions as potential dietary strategies to optimize the absorption of fat-soluble compounds.

CLINICAL TRIAL REGISTRY

The present trial was registered at clinicaltrials.gov (NCT04323826), link: https://clinicaltrials.gov/ct2/show/NCT04323826.

Digestion behavior, in vitro and in vivo bioavailability of cannabidiol in emulsions stabilized by whey protein-maltodextrin conjugate: Impact of carrier oil

An emulsion delivery system may be affected significantly by oil phase composition in terms of digestion behavior and bioavailability of the delivered substance. In this study, emulsions loaded with cannabidiol (CBD) were prepared with medium chain triglyceride (MCT), long chain triglyceride (LCT) or MCT/LCT(1:1) as carrier oil and whey protein-maltodextrin conjugate as emulsifier, and the digestion behavior of emulsion and bioavailability of CBD were assessed in vitro and in vivo. The particle size of emulsions throughout the in vitro digestion process was in the order of MCT < MCT/LCT < LCT, and three emulsions showed consistent particle size changes: stable in oral phase, sharply increased in gastric phase, and decreased in small intestine. After intestinal digestion, about 90% of free fatty acids (FFA) was released in MCT emulsion, followed by MCT/LCT (76%) and then LCT (45%). CBD was degraded during gastrointestinal digestion and the transformation stability of CBD in oil phase was in the order of LCT > MCT/LCT > MCT. Although CBD had higher bioaccessibility in MCT and MCT/LCT emulsions, the bioavailability of CBD in LCT was the highest (43%), followed by MCT/LCT (39%), MCT (33%). In vivo pharmacokinetic study showed that MCT/LCT and LCT were more favorable for CBD transport and absorption. The results may provide useful information for the construction of delivery systems, protecting CBD molecules, and improving their bioavailability.

In Vitro-In Vivo Study of the Impact of Excipient Emulsions on the Bioavailability and Antioxidant Activity of Flavonoids: Influence of the Carrier Oil Type

The influence of the carrier oil type on the bioavailability and bioactivity of flavonoids (quercetin, kaempferol, and apigenin) was examined using in vitro digestion, in situ intestinal perfusion, and pharmacokinetic studies. Here, medium-chain triglycerides (MCTs), long-chain triglycerides (LCTs), or MCT/LCT mixtures (1:1, w/w) served as the oil phase of excipient emulsions. Overall, the bioavailability and antioxidant activity of flavonoids increased when they were coingested with excipient emulsions. The in vitro bioaccessibility of flavonoids was affected by the carrier oil: LCT (17.9-22.8%) > MCT/LCT (12.1-13.7%) > MCT (9.2-12.6%). These differences were mainly attributed to the fact that the mixed micelles formed after the digestion of LCTs had larger hydrophobic domains to solubilize more flavonoids. However, in vivo pharmacokinetic experiments showed that the flavonoid concentrations in rat serum were comparable for all carrier oils (p > 0.05). Our results assist in formulating excipient emulsions to enhance the efficacy of flavonoids.

Storage stability and in vitro digestion of apigenin encapsulated in Pickering emulsions stabilized by whey protein isolate–chitosan complexes

Few studies have investigated the encapsulation of apigenin in solid particle-stabilized emulsions. In this work, Pickering emulsions containing apigenin and stabilized by whey protein isolate-chitosan (WPI-CS) complexes were created to enhance the bioavailability of apigenin. Different lipids including medium-chain triglycerides (MCTs), ethyl oleate (EO), and corn oil (CO) were selected to fabricate lipid-based delivery systems. The microstructure of the Pickering emulsions, as revealed by optical and cryo-scanning electron microscopies, showed that the oil droplets were dispersed evenly and trapped by a three-dimensional network formed by the WPI-CS complexes, which was further confirmed by rheology properties. After 30 days of storage, Pickering emulsions with MCTs achieved the highest apigenin retention rate, exhibiting 95.05 ± 1.45% retention when stored under 4°C. In vitro gastrointestinal tract experiments indicated that the lipid types of the emulsions also affected the lipid digestion and release rate of apigenin. Pickering emulsions with MCTs achieved a higher bioaccessibility compared to that of the other two emulsions (p < 0.01). These results indicate that the delivery system of Pickering emulsions with MCTs stabilized by WPI-CS complexes offers good storage stability and improved bioaccessibility of apigenin.

Mechanisms of carotenoid intestinal absorption and the regulation of dietary lipids: lipid transporter-mediated transintestinal epithelial pathways

Dietary lipids are key ingredients during cooking, processing, and seasoning of carotenoid-rich fruits and vegetables, playing vitals in affecting the absorption and utilization of carotenoids for achieving their health benefits. Besides, dietary lipids have also been extensively studied to construct various delivery systems for carotenoids, such as micro/nanoparticles, micro/nanoemulsions, and liposomes. Currently, the efficacies of these techniques on improving carotenoid bioavailability are often evaluated using the micellization rate or "bioaccessibility" based on in vitro models. However, recent studies have found that dietary lipids may also affect the carotenoid uptake via intestinal epithelial cells and the efflux of intracellular chyle particles via lipid transporters. An increasing number of studies reveal the varied impact of different dietary lipids on the absorption of different carotenoids and some lipids may even have an inhibitory effect. Consequently, it is necessary to clarify the relationship between the addition of dietary lipids and the intestinal absorption of carotenoid to fully understand the role of lipids during this process. This paper first introduces the intestinal absorption mechanism of carotenoids, including the effect of bile salts and lipases on mixed micelles, the types and regulation of lipid transporters, intracellular metabolizing enzymes, and the efflux process of chyle particles. Then, the regulatory mechanism of dietary lipids during intestinal carotenoid absorption is further discussed. Finally, the importance of selecting the dietary lipids for the absorption and utilization of different carotenoids and the design of an efficient delivery carrier are emphasized. This review provides suggestions for precise dietary carotenoid supplementation and offere an important reference for constructing efficient transport carriers for liposoluble nutrients.

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.

Superior Bioavailability of a Novel Lutein and Zeaxanthin Formulation in Healthy Human Subjects

Introduction

Lutein (L) and zeaxanthin (Z) are carotenoids that are found in the macula of the human eye and are known to improve visual functions. However, poor bioavailability of supplemental L and Z poses a challenge to achieving significant benefits after consumption. We developed a novel patented formulation of L and Z (Ocusorb^®) and demonstrated the improved bioavailability in a pharmacokinetic clinical study.

Methods

Ninety adult human volunteers were recruited in this randomized, double-blind, parallel, comparative bioavailability study. Volunteers were randomly assigned to receive single dose of 10 mg lutein and 2 mg zeaxanthin from test (LZO) or reference (LZC) formulations after breakfast. Blood samples were collected pre-dose at − 48, − 24, and 0 h and at 2, 4, 6, 8, 10, 12, 16, 20, 24, 48, and 72 h post-dose. Serum concentrations of L and Z were quantified by using a validated HPLC method. The LZO and LZC formulations were compared for L and Z on the basis of C_max, AUC_0–72, and AUC_0–t.

Results

All 90 subjects completed the study. The LZO group demonstrated significantly higher levels of L and Z in serum at several time points as compared to LZC group. The LZO group showed significantly higher bioavailability for lutein (2.5 times higher C_max, 2.9 times higher AUC_0–72, and 3.2 times higher AUC_0–t) and zeaxanthin (1.8 times higher C_max, 2.2 times higher AUC_0–72, and AUC_0–t) as compared to the LZC group. No safety issues were reported.

Conclusion

The study results show superior bioavailability of lutein and zeaxanthin from our novel LZO formulation as compared to LZC. The enhanced bioavailability from the LZO formulation can be advantageous for individuals looking to quickly improve their L and Z status and enhance their vision performance.

Trial Registration

http://ctri.nic.in/. Identifier: CTRI/2019/11/022082.

Self-assembled nano-micelles of lactoferrin peptides: Structure, physicochemical properties, and application for encapsulating and delivering curcumin

Food-derived protein hydrolysate exhibits good bioactivity, compatibility, and low toxicity, etc. However, the information on protein hydrolysate-based micelles and their application as carriers for hydrophobic bioactive compounds is limited. In this study, an enzymatic partially hydrolyzed lactoferrin hydrolysate nano-micelle with the size within 50 nm was constructed, and its formation mechanism and delivery characteristics for curcumin (Cur) were studied. The results demonstrated that Cur was loaded into the micelles through hydrophobic interaction, and the encapsulation rate of Cur by nano-micelles was (93.44 ± 0.01)%. In addition, the nano-micelle system demonstrated excellent thermal stability, dilution stability, and storage stability. The in vitro simulated digestion proved that self-assembled nano-micelles could improve the transformation rate and bioaccessibility of Cur. This study revealed that lactoferrin hydrolysate self-assembled nano-micelle is a promising delivery system for hydrophobic bioactive compounds.

In vitro bioaccessibility of vitamin K (phylloquinone and menaquinones) in food and supplements assessed by INFOGEST 2.0 – vit K

Vitamin K describes a group of fat-soluble vitamers namely phylloquinone and menaquinones. The growing evidence for vitamin K's role beyond blood coagulation, and the possible differences between the vitamers are emerging. Knowledge of the content of menaquinones in different food matrixes and the potential differences in bioaccessibility between the vitamin K vitamers and food matrixes are limited. In this study, the bioaccessibility was assessed using the INFOGEST 2.0 static in vitro digestion model optimised by including a Danish standard meal. The presence of the standard meal was crucial to obtaining a robust and stable digestion model. The bioaccessibility of the Danish standard meal, water, vitamin K standards, vitamin K supplements, broccoli, spinach, natto, pasteurised whole egg and canola oil was assessed by three replications. The bioaccessibility was in the range 30%–102%. The lowest bioaccessibility was observed in broccoli while the highest bioaccessibility was found in egg and canola oil. No competition in the bioaccessibility between vitamin K vitamers and vitamin D was observed.

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The INFOGEST 2.0 method was optimised for vitamin K research (INFOGEST 2.0 – vit K).

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INFOGEST 2.0 – vit K includes a standard meal based on a typical Danish meal.

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Addition of the standard meal ensures a stable and concentration independent model.

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The bioaccessibility (bioacc) of PK, MK-4 to MK-10 depended on the food matrix.

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The highest bioacc was found in oil, then supplements, followed by broccoli.

Effects of dietary fats on the bioaccessibility and bioavailability of carotenoids: a systematic review and meta-analysis of in vitro studies and randomized controlled trials

CONTEXT

Dietary fats are one of the well-known stimulators of carotenoid absorption, but the effects of the quantity and the type of dietary fats on carotenoid absorption have not yet been studied systematically.

OBJECTIVE

This review aimed to analyze data from both in vitro studies and randomized controlled trials (RCTs) to examine the effects of dietary fats on the bioaccessibility and bioavailability of carotenoids.

DATA SOURCES

A systematic search of 5 databases (Scopus, PubMed, Embase, CINAHL and the Cochrane Library) was conducted.

STUDY SELECTION

In vitro studies and RCTs were selected according to the PICOS criteria and were reviewed independently by 2 investigators.

DATE EXTRACTION

Key study characteristics from the eligible in vitro studies and RCTs were extracted independently by 2 investigators using a standardized table.

RESULTS

A total of 27 in vitro studies and 12 RCTs were included. The meta-regression of in vitro studies showed that the bioaccessibility of carotenoids, except for lycopene, was positively associated with the concentration of dietary fats. The meta-analysis of RCTs showed that the bioavailability of carotenoids was enhanced when a higher quantity of dietary fats was co-consumed. Moreover, fats rich in unsaturated fatty acids resulted in greater improvement in carotenoid bioavailability (SMD 0.90; 95%CI, 0.69-1.11) as compared with fats rich in saturated fatty acids (SMD 0.27; 95%CI, 0.08-0.47).

CONCLUSIONS

Co-consuming dietary fats, particularly those rich in unsaturated fatty acids, with carotenoid-rich foods can improve the absorption of carotenoids.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration number CRD42020188539.

Comparison of Lutein Bioaccessibility from Dietary Supplement-Excipient Nanoemulsions and Nanoemulsion-Based Delivery Systems

The impact of lutein-loaded nanoemulsions and excipient nanoemulsions mixed with lutein-based dietary supplements (capsules and soft gels) on the bioaccessibility of lutein was explored using a simulated gastrointestinal tract (GIT). The particle size, particle size distribution, ζ-potential, microstructure, lipid digestibility, and lutein bioaccessibility of all the samples were measured after they were exposed to different environments (stomach and small intestine environments) within a simulated GIT. As expected, the bioaccessibility of lutein from the capsules (1.5%) and soft gels (3.2%) was relatively low when they were administered alone. However, the co-administration of excipient nanoemulsions significantly increased the bioaccessibility of lutein from both the capsules (35.2%) and soft gels (28.7%). This phenomenon was attributed to the fast digestion of the small oil droplets in the excipient nanoemulsions and the further formation of mixed micelles to solubilize any lutein molecules released from the supplements. The lutein-loaded nanoemulsions exhibited a much higher lutein bioaccessibility (86.8%) than any of the supplements, which was attributed to the rapid release and solubilization of lutein when the lipid droplets were rapidly and extensively digested within the small intestine. This study indicates that the bioaccessibility of lutein is much higher in nanoemulsion droplets than that in dietary supplements. However, consuming dietary supplements in the presence of nanoemulsion droplets can greatly increase lutein bioavailability. The results of this study have important guiding significance for the design of more effective lutein supplements.

Encapsulation of Lutein via Microfluidic Technology: Evaluation of Stability and In Vitro Bioaccessibility

Inadequate intake of lutein is relevant to a higher risk of age-related eye diseases. However, lutein has been barely incorporated into foods efficiently because it is prone to degradation and is poorly bioaccessible in the gastrointestinal tract. Microfluidics, a novel food processing technology that can control fluid flows at the microscale, can enable the efficient encapsulation of bioactive compounds by fabricating suitable delivery structures. Hence, the present study aimed to evaluate the stability and the bioaccessibility of lutein that is encapsulated in a new noodle-like product made via microfluidic technology. Two types of oils (safflower oil (SO) and olive oil (OL)) were selected as a delivery vehicle for lutein, and two customized microfluidic devices (co-flow and combination-flow) were used. Lutein encapsulation was created by the following: (i) co-flow + SO, (ii) co-flow + OL, (iii) combination-flow + SO, and (iv) combination-flow + OL. The initial encapsulation of lutein in the noodle-like product was achieved at 86.0 ± 2.7%. Although lutein’s stability experienced a decreasing trend, the retention of lutein was maintained above 60% for up to seven days of storage. The two types of device did not result in a difference in lutein bioaccessibility (co-flow: 3.1 ± 0.5%; combination-flow: 3.6 ± 0.6%) and SO and OL also showed no difference in lutein bioaccessibility (SO: 3.4 ± 0.8%; OL: 3.3 ± 0.4%). These results suggest that the types of oil and device do not affect the lutein bioaccessibility. Findings from this study may provide scientific insights into emulsion-based delivery systems that employ microfluidics for the encapsulation of bioactive compounds into foods.

Bioaccessibility of microalgae-based carotenoids and their association with the lipid matrix

The composition of microalgae can contribute to nutritious and functional diets. Among the functional compounds, carotenoids are in focus since positive effects on human health have been established, which are in turn related to their bioaccessibility. In addition to essential nutrients, our hypothesis was that microalgae biomasses could be used as sources of bioaccessible carotenoids. Thus, this study determined for the first time the bioaccessibility of carotenoids from biomass of Scenedesmus bijuga and Chlorella sorokiniana and their possible relationship with the lipid composition of the matrix. The samples were submitted to in vitro digestion protocol, and carotenoids were determined by HPLC-PDA-MS/MS. Individual bioaccessibility of carotenoids was ≥ 3.25%. In general, compounds in their cis conformation were more bioaccessible than trans; and total carotenes more than total xanthophylls. Twelve compounds were bioaccessible from the biomass of S. bijuga, and eight in C. sorokiniana. In S. bijuga, the bioaccessibility of total carotenoids was 7.30%, and the major bioaccessible carotenoids were 9-cis-β-carotene (43.78%), 9-cis-zeaxanthin (42.30%) followed by 9-cis-lutein (26.73%); while in C. sorokiniana, the total bioaccessibility was 8.03%, and 9-cis-β-carotene (26.18%), all-trans-β-carotene (13.56%), followed by 13-cis-lutein (10.71%) were the major compounds. Overall, the total content of lipids does not influence the bioaccessibility of total carotenoids. Still, the lipid composition, including structural characteristics such as degree of saturation and chain length of the fatty acid, impacts the promotion of individual bioaccessibility of carotenes and xanthophylls of microalgae. Finally, the results of this study can assist the development of microalgae-based functional food ingredients and products.

Improvement of stability and bioaccessibility of β-carotene by curcumin in pea protein isolate-based complexes-stabilized emulsions: Effect of protein complexation by pectin and small molecular surfactants

The impact of different complexes on the properties of β-carotene-loaded emulsions was investigated by measuring the droplet size, encapsulation efficiency, droplet morphology, and physical stability. The photo and thermal stability of β-carotene and its bioaccessibility during digestion were also analyzed. Comparing to the emulsions stabilized by other complexes, the emulsion stabilized by the high methoxyl pectin-rhamnolipid-pea protein isolate-curcumin (HMP-Rha-PPI-Cur) complex had the smallest droplet size (17.53 ± 0.15 μm) and the maximum encapsulation efficiency for curcumin (90.33 ± 0.03 %) and β-carotene (92.16 ± 0.01 %). The emulsion stabilized by the HMP-Rha-PPI-Cur complex exhibited better physical stability against creaming. The retention rate of β-carotene in the HMP-Rha-PPI-Cur complex-stabilized emulsion was 17.75 ± 0.02 and 33.64 ± 0.02 % after UV irradiation and thermal treatment. The HMP-Rha-PPI-Cur complex-stabilized emulsion also had a higher level of free fatty acid released (43.67 %) and higher bioaccessibility of β-carotene (32.35 ± 0.02 %).

Carotenoids in Milk and the Potential for Dairy Based Functional Foods

Carotenoids are a family of over 1100 known natural pigments synthesized by plants, algae, fungi and bacteria. Dietary intake of carotenoids is necessary for mammals as they cannot be synthesized in the body. In cows, the nature of the diet consumed strongly influences the composition of milk produced and this includes carotenoid concentration and profile. Fresh forage is the richest source of carotenoids for cows. The main carotenoids identified in forages are lutein, β-carotene, zeaxanthin and epilutein. Manipulating cow feed via carotenoid supplementation increases the carotenoid content of bovine milk. In humans, carotenoids have anti-oxidant, anti-inflammatory and provitamin A activity. Lutein is a major carotenoid in human milk and the brain tissue of adults and infants. Lutein and zeaxanthin are linked to improved eye health and cognitive function. Traditionally for humans, fruit and vegetables have been the main source of carotenoid intake. Functional foods present an opportunity to incorporate these naturally occurring compounds into milk products for added health benefits, widening the range of dietary sources of carotenoids. We offer an overview of the literature to date on carotenoid-fortified dairy products and infant formula. This review will describe and summarize the key mechanisms by which the carotenoid profile of bovine milk can be manipulated. We present findings on the origin and role of carotenoids in bovine and human milk, outline factors that impact the carotenoid content of milk, evaluate carotenoid-fortified milk products and discuss the associated challenges, such as bioaccessibility and stability.

In vitro bioaccessibility of macular xanthophylls from commercial microalgal powders of Arthrospira platensis and Chlorella pyrenoidosa

The bioaccessibility of the major carotenoids present in two commercial microalgal supplements in powder form was investigated through a standardized in vitro digestion method. The dried biomass of Arthrospira platensis contained β-carotene (36.8 mg/100 g) and zeaxanthin (20.8 mg/100 g) as the main carotenoids as well as a high content of saturated fatty acids (61% of total fatty acids), whereas that of Chlorella pyrenoidosa was rich in lutein (37.8 mg/100 g) and had a high level of unsaturated fatty acids (65% of total fatty acids). In the case of the latter, lutein bioaccessibility was not statistically enhanced after the replacement of porcine bile extract with bovine bile extract in the in vitro digestion protocol and after the addition of coconut oil (17.8% as against to 19.2% and 19.2% vs. 18.5%, respectively). In contrast, the use of bovine bile extract along with co-digestion with coconut oil significantly enhanced the bioaccessibility of zeaxanthin from A. platensis, reaching the highest bioaccessibility of 42.8%.

Remodeling of β-Carotene-Encapsulated Protein-Stabilized Nanoparticles during Gastrointestinal Digestion In Vitro and in Mice

The remodeling of β-carotene-encapsulated protein nanoparticles (NPs) during digestion in vitro and in vivo was investigated. The NPs were formed using three different proteins. Hydrolysis of the surface protein during digestion resulted in structure remodeling of NPs and the formation of small-sized micellar-like aggregates below 100 nm, accelerating the release of β-carotene into the aqueous phase. However, the reduced surface ζ-potential in the intestinal fluid suggested the adsorption of bile salts, favoring the formation of small-sized micellar-like aggregates. A shifted peak of β-carotene in the micellar phase from 965 cm^-1 to about 855 cm^-1 in Fourier transform infrared spectroscopy analysis indicated that β-carotene existed in the amorphous state. Microstructure observation in vivo further confirmed that β-carotene was loaded in micellar-like aggregates and dispersed uniformly in water. The cellular uptake study showed that the absorption rate of digested NPs was significantly increased by 1.34- to 4.16-fold when compared with undigested NPs.

Advances in edible nanoemulsions: Digestion, bioavailability, and potential toxicity

The design, fabrication, and application of edible nanoemulsions for the encapsulation and delivery of bioactive agents has been a highly active research field over the past decade or so. In particular, they have been widely used for the encapsulation and delivery of hydrophobic bioactive substances, such as hydrophobic drugs, lipids, vitamins, and phytochemicals. A great deal of progress has been made in creating stable edible nanoemulsions that can increase the stability and efficacy of these bioactive agents. This article highlights some of the most important recent advances within this area, including increasing the water-dispersibility of bioactives, protecting bioactives from chemical degradation during storage, increasing the bioavailability of bioactives after ingestion, and targeting the release of bioactives within the gastrointestinal tract. Moreover, it highlights progress that is being made in creating plant-based edible nanoemulsions. Finally, the potential toxicity of edible nanoemulsions is considered.

Improvement of carotenoid bioaccessibility from spinach by co-ingesting with excipient nanoemulsions: impact of the oil phase composition

Many of the carotenoids found naturally in fruits and vegetables are beneficial to human health, but they often have low oral bioavailability because of their high hydrophobicity. In this study, the effects of varying the composition of the oil phase of excipient nanoemulsions on carotenoid bioaccessibility from spinach were investigated using a simulated gastrointestinal tract. Nanoemulsions containing different ratios of medium chain triglycerides (MCT) and long chain triglycerides (LCT) were prepared: (i) mixing MCT and LCT oils before homogenization and (ii) mixing MCT droplets with LCT droplets after homogenization. The release of carotenoids from spinach and their solubilization within the mixed micelles formed after lipid digestion depended strongly on the oil phase composition. As expected, carotenoid bioaccessibility was always higher in the presence of excipient nanoemulsions than in their absence. The total free fatty acids released in the small intestine increased as the MCT/LCT ratio increased, which can be attributed to the faster release of shorter chain fatty acids from the oil droplet surfaces during lipid digestion. As the MCT ratio increased, lutein bioaccessibility increased but β-carotene bioaccessibility decreased. This difference was attributed to the ability of the formed mixed micelles to accommodate the two different kinds of carotenoids in their hydrophobic domains. Interestingly, carotenoid bioaccessibility was significantly lower (P < 0.05) when the oil droplets were mixed after homogenization than when the oils were mixed before homogenization. These results have important implications for the design of excipient foods to improve the bioavailability of hydrophobic nutraceuticals in fruits and vegetables.