Anthocyanin-rich Bilberry Extract Research Articles

Encapsulation of Bilberry Extract with Maltodextrin and Gum Arabic by Freeze-Drying: Formulation, Characterisation, and Storage Stability

Anthocyanins are polyphenolic plant pigments associated with antioxidant and health-promoting properties. However, their application in the food industry is limited due to their poor stability. The purpose of this study was to encapsulate anthocyanin-rich bilberry (Vaccinium myrtillus L.) extract by freeze-drying and to investigate the effects of different wall materials and extract contents on the physicochemical and bioactive properties of the obtained encapsulates. Ethanolic bilberry extract was encapsulated with the use of maltodextrin (16.5–19.5 DE) (MD), gum Arabic (GA), and their combination in a 1:1 w/w ratio (MIX). Bilberry solids to wall material ratios were examined at 20:80, 30:70, and 40:60. All encapsulates showed an attractive red colour and low water activity values (aw ≤ 0.3) that indicated a low risk of microbial spoilage. In general, the biggest losses of total phenolic compounds and anthocyanins during three-week storage in the dark and at room temperature (20 ± 2 °C) were detected in the case of encapsulates with a higher content of bilberry extract (MIX30 and MIX40, and GA30 and GA40, respectively). The use of maltodextrin provided the best protection to bilberry anthocyanins during forced storage. Overall, the obtained encapsulates show suitable potential for the development of food products with added nutritional benefits.

The Effects of Anthocyanin-Rich Bilberry Extract on Transintestinal Cholesterol Excretion.

Hypercholesterolemia is one of the modifiable and primary risk factors for cardiovascular diseases (CVD). Emerging evidence suggests the stimulation of transintestinal cholesterol excretion (TICE), the nonbiliary cholesterol excretion, using natural products can be an effective way to reduce CVD. Bilberry (Vaccinium myrtillus L.) has been reported to have cardioprotective effects by ameliorating oxidative stress, inflammation, and dyslipidemia. However, the role of bilberry in intestinal cholesterol metabolism is not well understood. To examine the effects of bilberry in intestinal cholesterol metabolism, we measured the genes for cholesterol flux and de novo synthesis in anthocyanin-rich bilberry extract (BE)-treated Caco-2 cells. BE significantly decreased the genes for cholesterol absorption, i.e., Niemann-Pick C1 Like 1 and ATP-binding cassette transporter A1 (ABCA1). In contrast, BE significantly upregulated ABCG8, the apical transporter for cholesterol. There was a significant induction of low-density lipoprotein receptors, with a concomitant increase in cellular uptake of cholesterol in BE-treated cells. The expression of genes for lipogenesis and sirtuins was altered by BE treatment. In the present study, BE altered the genes for cholesterol flux from basolateral to the apical membrane of enterocytes, potentially stimulating TICE. These results support the potential of BE in the prevention of hypercholesterolemia.

Nutrigenomic modification induced by anthocyanin-rich bilberry extract in the hippocampus of ApoE-/- mice

Dietary anthocyanins may slow cognitive decline, improve cognitive performance and exert neuroprotective effects against neurodegenerative disorders. However, the underlying mechanisms of their action are not fully understood. This study investigated the effects of 12-week anthocyanin-rich bilberry extract supplementation (0.02%) on global gene expression in the hippocampus of ApoE-/- mice to help the understanding of molecular mechanisms underlying anthocyanin neuroprotective effects. Gene expression analysis identified 1698 differently expressed genes, with 611 downregulated and 1087 upregulated genes. Bioinformatics revealed that these genes regulate different biological processes, including neurogenesis, inflammation, metabolism, cell to cell adhesion, cytoskeleton organization, and Alzheimer's and Parkinson's disease pathology. The bioinformatic analysis also proposed potential miRNAs and transcription factors that could be involved in the mediation of these nutrigenomic effects. Results from molecular docking also suggested that anthocyanins could bind to top transcription factors with, as potential consequence, an impact on their gene expression regulation. Taken together, integrated analysis revealed a multi-target mode of action of anthocyanin-rich bilberry extract in the hippocampus underlying their neuroprotective properties.

In vitro and in vivo inhibitory effect of anthocyanin-rich bilberry extract on α-glucosidase and α-amylase

The inhibition of glycosidase activity is regarded as an effective treatment for diabetes mellitus. Bilberry (Vaccinium myrtillus L.) fruit has a high content of anthocyanins with various biological activities. The objective of this study was to investigate the inhibitory activity of anthocyanin-rich bilberry extract (BE) on α-glucosidase and α-amylase and their interaction mechanisms in vitro. The IC50 values of BE with regard to α-glucosidase and α-amylase inhibition were 0.31 ± 0.02 and 4.06 ± 0.12 mg/mL, respectively. The enzyme kinetics revealed that BE acts as a mixed-type inhibitor against α-glucosidase and α-amylase. Moreover, the fluorescence of two glucosidases showed significant quenching by BE. FTIR spectra and differential scanning calorimetry (DSC) indicated that BE changed the enzyme structure and decreased its stability. A morphological observation of starch granules found that BE inhibited the activity of α-amylase to postpone the hydrolysis of starch. Furthermore, the in vivo study further showed that BE had a hypoglycaemic effect. The most suitable conformation (main anthocyanidins of BE) and optimal binding site (α-glucosidase, α-amylase) were assayed by molecular docking. In conclusion, this study revealed that BE could be a potential glycosidase inhibitor.

Differential protection by anthocyanin-rich bilberry extract and resveratrol against lipid micelle-induced oxidative stress and monolayer permeability in Caco-2 intestinal epithelial cells.

Excess dietary fat, and associated bile acids, can impair intestinal barrier integrity, produce intestinal or systemic inflammation and promote tumorigenesis. Dietary polyphenols in foods such as berries display antioxidant and other protective effects in many biological systems, but little is known about their protective effects on intestinal epithelial cells exposed to dietary fat. In a Caco-2 cell model of dietary fat-induced intestinal epithelial cell cytotoxicity, oxidative stress and barrier impairment, we investigated the relative protection afforded by an anthocyanin-rich bilberry extract (ARBE) or resveratrol. Exposure of the cells to mixed micelles (MM) of fatty acids and bile acids for 24 h markedly increased intracellular reactive oxygen species (ROS) and mitochondrial superoxide generation, decreased cell viability, increased expression of TNF-α mRNA and disrupted differentiated monolayer integrity. Starting prior to exposure to MM, treatments with ARBE or resveratrol, at polyphenol concentrations from 1.25-20 μM, strongly attenuated MM-induced intracellular ROS generation, and ARBE but not resveratrol decreased mitochondrial superoxide generation. Both ARBE and resveratrol inhibited the MM-induced expression of TNF-α mRNA. In assessments of differentiated monolayer integrity by transepithelial electrical resistance (TEER) and paracellular permeability, resveratrol protection was apparent at 3 h of MM exposure, but less at 6 h and absent by 9 h. In contrast, ARBE largely reversed MM-induced impairment by 9 h, with TEER values reaching 82% of control and the MM-induced paracellular permeability reduced by 78%. While they appeared to act differently, the results suggest that dietary sources of anthocyanins and resveratrol can help confer resistance of intestinal epithelial cells to oxidative stress and inflammation, and resultant barrier dysfunction and tumorigenesis, induced by high dietary fat common in the Western diet.

Protective effects of anthocyanin-rich bilberry (Vaccinium myrtillus L.) extract against copper(II) chloride toxicity.

In this study, the protective effects of 50 mg/L and 100 mg/L doses of anthocyanin-rich bilberry extracts (ABE) against the toxicity caused by 20 μM copper(II) chloride (CuCl2) on Allium cepa L. were investigated. Alterations in weight gain, germination percentage, and root elongation were evaluated as physiological parameters while micronucleus (MN), mitotic index (MI), and chromosomal abnormality (CA) frequency were studied as cytogenetic parameters. Oxidative stress indicators such as malondialdehyde (MDA) formation, superoxide dismutase (SOD) activity, and catalase (CAT) activity were analyzed and also damages in root tip meristem cells were determined by cross sections. As a result, it was found that the percentage of germination, weight gain, root length, and MI decreased and the frequency of MN and CAs increased with CuCl2 treatment. CuCl2 exposure caused a significant increase in SOD and CAT activities and MDA levels. A number of anatomical abnormalities and damages were detected in the cross sections of CuCl2-treated roots. On the other hand, ABE applications ameliorated notably all copper-induced damages in a dose-dependent manner. Therefore, the powerful protective potential of ABE against copper-induced toxicity was proven through an extensive study in a popular plant model.

Effect of anthocyanin-rich bilberry extract on bone metabolism in ovariectomized rats.

Menopause is associated with increased oxidative stress, which serves a role, in part, in the pathogenesis of postmenopausal bone loss. Fruits and vegetables are rich in antioxidative nutrients and phytochemicals. Berries are a natural source of anthocyanins, and their intake may improve bone health. The aim of the present study was to determine the effect of an anthocyanin-rich bilberry extract (VME) on bone metabolism in an ovariectomized (Ovx) rat. Female Sprague-Dawley rats (12 weeks old) were randomly divided into the following four groups: Baseline, Sham, Ovx and Ovx+VME (n=8-12 rats per group). Rats in the Baseline group were sacrificed immediately, while those in the other groups were subjected to either sham operation (Sham) or bilateral Ovx (Ovx and Ovx+VME). Rats in the Ovx+VME group were administered VME daily at a dose of 500 mg/kg body weight. At 8 weeks after surgery, bone mass and bone histomorphometry were evaluated. The femur bone mineral density (BMD) in the Ovx group was significantly lower than that in the Sham group (P<0.01). Supplementation of VME in the Ovx rats did not result in an increase in BMD. Histomorphometric analyses revealed that Ovx resulted in decreased measures of bone volume and trabecular number and increased measures of osteoid volume, mineralizing surface and bone formation rates (all P<0.01), whereas VME had no significant effects on these parameters. The present findings indicate that VME did not alter bone metabolism in Ovx rats, suggesting that consumption of VME may not be helpful in preventing postmenopausal bone loss.

Anthocyanins Prevent Colorectal Cancer Development in a Mouse Model

Background: Colorectal cancer is the main leading cause of cancer-related deaths worldwide. Present data suggest that plant-derived anthocyanins have anti-inflammatory and chemopreventive properties. This study was aimed at evaluating the effect of an anthocyanin-rich extract from bilberries on colorectal tumour development and growth in the administration of azoxymethan (AOM)/dextran sodium sulfate (DSS) mouse model. Methods: Colonic carcinogenesis was induced by AOM and DSS 3 or 5%, respectively, in 50 female Balb/c mice. Mice received either normal food (controls) or a diet containing either 10 or 1% anthocyanin-rich bilberry extract. Colonoscopy took place at week 4 and 9 after initiation of carcinogenesis. After termination at week 9, colon samples were analysed macroscopically and microscopically. Results: Mice receiving 10% anthocyanins showed significantly (p < 0.004) less reduced colon length (12.1 cm [8.5-14.4 cm]) as compared to controls (11.2 cm [9.8-12.3]) indicating less inflammation. Mice fed with 10% anthocyanin-rich extract revealed significantly less mean tumour numbers (n = 1.2) compared to control (n = 14) and anthocyanin 1% treated mice (n = 10.6, p < 0.001). Conclusion: Anthocyanins prevented the formation and growth of colorectal cancer in AOM/DSS-treated Balb/c mice. Further studies should investigate the mechanisms of how anthocyanins influence the development of colorectal cancer.

Bilberry-Derived Anthocyanins Modulate Cytokine Expression in the Intestine of Patients with Ulcerative Colitis.

Background/AimsWe previously demonstrated that anthocyanin-rich bilberry extract (ARBE) inhibits IFN-γ-induced signalling and downstream effects in human monocytic cells and ameliorates disease activity in ulcerative colitis (UC) patients. Here, we studied the molecular mechanisms of ARBE-mediated effects in vitro and by analysing colonic tissue and serum samples of UC patients treated with an oral anthocyanin-rich bilberry preparation during an open label clinical trial.MethodsColon specimens obtained during an open pilot study using ARBE for the treatment of mild-to-moderate UC were analyzed by immunohistochemistry. Cytokine levels in patients’ serum were quantified by ELISA. Cell culture experiments were performed using THP-1 monocytic cells.ResultsARBE treatment inhibited the expression of IFN-γ-receptor 2 in human THP-1 monocytic cells. Colon biopsies of UC patients who responded to the 6-week long ARBE treatment revealed reduced amounts of the pro-inflammatory cytokines IFN-γ and TNF-α. Levels of phosphorylated (activated) p65-NF-κB were reduced in these patients. Further, patients with successful ARBE treatment featured enhanced levels of Th17-cell specific cytokine IL-22 and immunoregulatory cytokine IL-10 as well as reduced serum levels of TNF-α and MCP-1, but enhanced levels of IL-17A, in contrast to patients that did not reach remission after ARBE treatment.ConclusionsOur data suggest a molecular mechanism underlying the anti-inflammatory effects of ARBE treatment in UC patients by modulating T-cell cytokine signalling and inhibiting IFN-γ signal transduction. These data are of particular interest, since ARBE is a promising therapeutic approach for the treatment of IBD.

Infrared Spectroscopy of Bilberry Extract Water-in-Oil Emulsions: Sensing the Water-Oil Interface.

Water-in-oil (w/o) emulsions are of great interest in many areas of the life sciences, including food technology, bioprocess engineering, and pharmaceuticals. Such emulsions are complex multi-component systems and the molecular mechanisms which lead to a stable emulsion are yet to be fully understood. In this work, attenuated total reflection (ATR) infrared (IR) spectroscopy is applied to a series of w/o emulsions of an aqueous anthocyanin-rich bilberry extract dispersed in a medium chain triglyceride (MCT) oil phase. The content of the emulsifier polyglycerin-polyricinoleat (PGPR) has been varied systematically in order to investigate whether or not its concentration has an impact on the molecular stabilization mechanisms. The molecular stabilization is accessed by a careful analysis of the IR spectrum, where changes in the vibrational frequencies and signal strengths indicate alterations of the molecular environment at the water/oil interface. The results suggest that adding emulsifier in excess of 1% by weight does not lead to an enhanced stabilization of the emulsion.

Effects of Anthocyanin and Flavanol Compounds on Lipid Metabolism and Adipose Tissue Associated Systemic Inflammation in Diet-Induced Obesity.

Background. Naturally occurring substances from the flavanol and anthocyanin family of polyphenols have been proposed to exert beneficial effects in the course of obesity. We hypothesized that their effects on attenuating obesity-induced dyslipidemia as well as the associated inflammatory sequelae especially have health-promoting potential. Methods. Male C57BL/6J mice (n = 52) received a control low-fat diet (LFD; 10 kcal% fat) for 6 weeks followed by 24 weeks of either LFD (n = 13) or high-fat diet (HFD; 45 kcal% fat; n = 13) or HFD supplemented with 0.1% w/w of the flavanol compound epicatechin (HFD+E; n = 13) or an anthocyanin-rich bilberry extract (HFD+B; n = 13). Energy substrate utilization was determined by indirect calorimetry in a subset of mice following the dietary switch and at the end of the experiment. Blood samples were collected at baseline and at 3 days and 4, 12, and 20 weeks after dietary switch and analyzed for systemic lipids and proinflammatory cytokines. Adipose tissue (AT) histopathology and inflammatory gene expression as well as hepatic lipid content were analyzed after sacrifice. Results. The switch from a LFD to a HFD lowered the respiratory exchange ratio and increased plasma cholesterol and hepatic lipid content. These changes were not attenuated by HFD+E or HFD+B. Furthermore, the polyphenol compounds could not prevent HFD-induced systemic rise of TNF-α levels. Interestingly, a significant reduction in Tnf gene expression in HFD+B mice was observed in the AT. Furthermore, HFD+B, but not HFD+E, significantly prevented the early upregulation of circulating neutrophil chemoattractant mKC. However, no differences in AT histopathology were observed between the HFD types. Conclusion. Supplementation of HFD with an anthocyanin-rich bilberry extract but not with the flavanol epicatechin may exert beneficial effects on the systemic early inflammatory response associated with diet-induced obesity. These systemic effects were transient and not observed after prolongation of HFD-feeding (24 weeks). On the tissue level, long-term treatment with bilberry attenuated TNF-α expression in adipose tissue.

Mirtoselect, an anthocyanin-rich bilberry extract, attenuates non-alcoholic steatohepatitis and associated fibrosis in ApoE∗3Leiden mice

Anthocyanins may have beneficial effects on lipid metabolism and inflammation and are demonstrated to have hepatoprotective properties in models of restraint-stress- and chemically-induced liver damage. However, their potential to protect against non-alcoholic steatohepatitis (NASH) under conditions relevant for human pathogenesis remains unclear. Therefore, we studied the effects of the standardised anthocyanin-rich extract Mirtoselect on diet-induced NASH in a translational model of disease. ApoE(∗)3Leiden mice were fed a Western-type cholesterol-containing diet without (HC) or with 0.1% (w/w) Mirtoselect (HCM) for 20weeks to study the effects on diet-induced NASH. Mirtoselect attenuated HC-induced hepatic steatosis, as observed by decreased macro- and microvesicular hepatocellular lipid accumulation and reduced hepatic cholesteryl ester content. This anti-steatotic effect was accompanied by local anti-inflammatory effects in liver, as demonstrated by reduced inflammatory cell clusters and reduced neutrophil infiltration in HCM. On a molecular level, HC diet significantly induced hepatic expression of pro-inflammatory genes Tnf, Emr1, Ccl2, Mpo, Cxcl1, and Cxcl2 while this induction was less pronounced or significantly decreased in HCM. A similar quenching effect was observed for HC-induced pro-fibrotic genes, Acta2 and Col1a1 and this anti-fibrotic effect of Mirtoselect was confirmed histologically. Many of the pro-inflammatory and pro-fibrotic parameters positively correlated with intrahepatic free cholesterol levels. Mirtoselect significantly reduced accumulation and crystallisation of intrahepatic free cholesterol, providing a possible mechanism for the observed hepatoprotective effects. Mirtoselect attenuates development of NASH, reducing hepatic lipid accumulation, inflammation and fibrosis, possibly mediated by local anti-inflammatory effects associated with reduced accumulation and crystallisation of intrahepatic free cholesterol.

Fractionation of an anthocyanin-rich bilberry extract and in vitro antioxidative activity testing

The incidence of chronic diseases increases with advancing age of the population. A commonly discussed cause of chronic diseases is oxidative stress, which occurs in the body when there is an imbalance between the formation and inactivation of so-called reactive oxygen species (ROS). Epidemiological data suggest that a ‘healthy diet’, with a high content of flavonoids indicates preventive properties and correlates with an inverse effect with respect to the risk of chronic diseases. Berries (especially bilberries, Vaccinium myrtillus L.) are an important source of these flavonoids.In this study, we investigated, in vitro, the antioxidative properties of fractions obtained from a commercially available anthocyanin-rich bilberry extract (BE). As markers for antioxidative activity, the intracellularly generated ROS levels, oxidative DNA damage, and total glutathione (tGSH) levels were determined in the human colon cell lines Caco-2 and HT-29.In Caco-2 cells, the ROS levels and, in both cell lines, the oxidative DNA damage, were significantly reduced in the presence of the original BE and phenolcarbonic acid-rich fraction. Total GSH levels were slightly increased after pretreatment with BE, phenolcarbonic acid and the polymeric fractions, but not with the anthocyanin fraction.In summary, the BE and the therefrom-isolated phenolcarbonic acid-rich fraction, showed the most potent antioxidative activity whereas the polymeric and anthocyanin-rich fraction, in total, were less active.

Is the antioxidative effectiveness of a bilberry extract influenced by encapsulation?

Bilberries (Vaccinium myrtillus L.) have been suggested to have preventive properties against diseases associated with oxidative stress such as colon cancer or inflammatory bowel diseases. Therefore the gastrointestinal tract is regarded as a potential target for prevention. In this study the antioxidative properties of a commercially available anthocyanin-rich bilberry extract (BE) were investigated in comparison with four different BE-loaded microcapsule systems. As markers to describe the antioxidant status in this cellular system, intracellular reactive oxygen species (ROS) levels, oxidative DNA damage and total glutathione (tGSH) levels were monitored. Incubations with the BE-loaded capsule systems showed an increase in cellular glutathione levels and reduction of ROS levels at high BE concentrations (100-500 µg mL(-1) ) and a positive effect on the formation of DNA strand breaks (5-10 µg mL(-1) BE). The biological properties of BE-loaded pectin amide core-shell capsules, whey protein matrix capsules and coated apple pectin matrix capsules were comparable to those of the non-encapsulated BE. Overall, the BE and the encapsulated BE types tested have antioxidative activity under the studied assay conditions in terms of the prevention of oxidative DNA damage, the reduction of intracellular ROS and the enhancement of cellular tGSH.

TRIGGERED GASTROINTESTINAL RELEASE OF ANTHOCYANINS FROM BILBERRIES (VACCINIUM MYRTILLUS L.)

Bilberries (Vaccinium myrtillus L.) are reported to show preventive activities against inflammatory bowel diseases (IBD), colon cancer or degenerative disease such as Alzheimer’s dementia. These findings are attributed to the antioxidative and anti-inflammatory activities of one of the main ingredients, the anthocyanins. However, anthocyanins are sensitive to environmental conditions, thus their bioavailability in the gastrointestinal tract is an important determinant of their in vivo activity. In the study reported here, the potential benefits of encapsulating an anthocyanin rich bilberry extract (BE) on anthocyanin stability were investigated. Non-encapsulated BE and three different BE loaded microcapsule systems were incubated anaerobically in intestinal fluid, namely ileostomy effluents from volunteers. After exposure to these media released anthocyanins were identified and quantified by HPLC with UV/VIS detection. A constant degradation of anthocyanins from BE was observed to 29.7% of the applied amount within 24 h. In contrast to this, encapsulation of anthocyanins lead to a constant liberation for at least 6 h of about 14.5 to 20.5% of the initial concentration of anthocyanins from the matrix. These results illustrate the ability of encapsulation to provide a constant (triggered) release of anthocyanins into the intestinal system, but in contrast to the non-encapsulated BE lower low amounts being liberated.

The senescence-accelerated mouse-prone 8 is not a suitable model for the investigation of cardiac inflammation and oxidative stress and their modulation by dietary phytochemicals

Aging is associated with chronic inflammation and oxidative stress, which both may promote age-associated disorders including cardiovascular diseases. The cardiovascular system suffers from the life-long impact of stressors, such as reactive oxygen and nitrogen species. A diet rich in vegetables and fruits, and thus phytochemicals, may extend healthy lifespan in humans, in part by improving heart health by lowering of oxidative stress and modulating signal transduction pathways. To investigate the potential impact of dietary anthocyanin-rich bilberry extract and curcumin on oxidative stress and inflammatory markers in the heart, two groups of senescence-accelerated mouse-resistant 1 (SAMR1) and senescence-accelerated mouse-prone 8 (SAMP8) mice, respectively, were fed a Western-type diet (normal control and aged control, respectively) and two groups of SAMP8 mice were fed either bilberry extract (20g/kg diet) or curcumin (500mg/kg diet) over a period of 5 months. An activation of the transcription factor nuclear factor κ B (NFκB), but no differences in the gene and protein expression of NFκB-regulated pro-inflammatory mediators, was observed in the hearts of SAMP8 compared to SAMR1 control mice. Cardiac concentrations of protein and lipid oxidation parameters were similar in SAMR1 and SAMP8 control mice and the phytochemical-fed SAMP8 mice. Our data question the suitability of the SAMP8 and SAMR1 strains as a model for age-dependent changes of pro-inflammatory cytokines and oxidative stress in the heart.

Stability of Anthocyanin‐Rich W/O/W‐Emulsions Designed for Intestinal Release in Gastrointestinal Environment

Anthocyanins belong to the most important hydrophilic plant pigments. Outside their natural environment, these molecules are extremely unstable. Encapsulating them in submicron-sized containers is one possibility to stabilize them for the use in bioactivity studies or functional foods. The containers have to be designed for a target release in the human gastrointestinal system. In this contribution, an anthocyanin-rich bilberry extract was encapsulated in the inner aqueous phase of water-in-oil-in-water-double emulsions. The physical stability as well as the release of free fatty acids and encapsulated, bioactive substances from the emulsions during an in vitro gastrointestinal passage were investigated. The focus was on the influence of emulsion microstructural parameters (for example, inner and outer droplet size, disperse phase content) and required additives (emulsifier systems), respectively. It could be shown that it is possible to stabilize anthocyanins in the inner phase of double emulsions. The release rate of free fatty acids during incubation was independent of the emulsifier used. However, the exterior (O/W)-emulsifier has an impact on the stability of multiple emulsions in gastrointestinal environment and, thus, the location of release. Long-chained emulsifiers like whey proteins are most suitable to transport a maximum amount of bioactive substances to the effective location, being the small intestine for anthocyanins. In addition, it was shown that the dominating release mechanism for entrapped matter was coalescence of the interior W(1) -droplets with the surrounding W(2) -phase.

Antioxidant capacity of bilberry extract microencapsulated in whey protein hydrogels

The application of antioxidative phenolic plant compounds, such as bilberry anthocyanins, as bioactive food additive may be facilitated by the protection through microencapsulation. The antioxidant capacity of the encapsulated compounds could thus be preserved until the point of action is reached. In this study, whey protein-based microcapsules loaded with an anthocyanin-rich bilberry extract were generated thermally after forming droplets by the emulsion method. The TEAC (Trolox equivalent antioxidant capacity)-assay was used to assess the antioxidant capacity of the anthocyanin-rich bilberry extract during all steps of the microencapsulation process. It could be shown that the loss of antioxidant capacity during microencapsulation can mainly be attributed to interactions between the whey proteins and bilberry extract compounds other than anthocyanins. An anthocyanin-attributed loss of antioxidant capacity occurred when an emulsifier was used in the microencapsulation process. In this case, a transition of hydrophilic anthocyanins to the oil phase was observed. Eventually, the generated bilberry-extract loaded microcapsules were investigated in terms of their release behaviour in digestive media. Due to the time-dependent diffusive release from the microcapsules, the degradation of anthocyanins at pH 6.8 was retarded in comparison to non-encapsulated bilberry-anthocyanins. However, anthocyanin degradation at pH 6.8 was minimal when the non-gelled bilberry extract–whey protein solution was incubated which indicates a protective effect of native whey proteins.The results of this study provide new insights regarding protein-based microencapsulation of phenolic compounds and are thus of relevance for the development of innovative encapsulation systems.

Preparation and Comparative Release Characteristics of Three Anthocyanin Encapsulation Systems

Bilberries (Vaccinium myrtillus L.) and their major polyphenolic constituents, anthocyanins, have preventive activities inter alia against colon cancer and inflammatory bowel diseases. However, anthocyanins are sensitive to environmental conditions; thus their bioavailability in the gastrointestinal tract is an important determinant of their in vivo activity. In the study reported here, the potential benefits of encapsulating an anthocyanin rich bilberry extract (BE) on anthocyanin stability were investigated. Nonencapsulated BE and three different BE loaded microcapsule systems were incubated in simulated gastric fluid (SGF) and fed state simulated intestinal fluid (FeSSIF). After exposure to these media, released anthocyanins were identified and quantified by HPLC with UV/Vis detection. Although a rapid release of anthocyanins was observed within the first 20 min, encapsulation of anthocyanins doubled the amount of available anthocyanins after 150 min of incubation. These results illustrate the ability of encapsulation to inhibit early degradation of anthocyanins in the intestinal system.

Vision preservation during retinal inflammation by anthocyanin-rich bilberry extract: cellular and molecular mechanism

Anthocyanin-rich bilberry extract, a plant-derived antioxidant, has been utilized as a popular supplement for ocular health worldwide. However, it is unclear whether this extract has any biological effect on visual function, and the mechanism for such an effect is completely unknown. In this study, we generated a mouse model of endotoxin-induced uveitis (EIU) that shows retinal inflammation, as well as uveitis, by injecting lipopolysaccharide. We pretreated the mice with anthocyanin-rich bilberry extract and analyzed the effect on the retina. Anthocyanin-rich bilberry extract prevented the impairment of photoreceptor cell function, as measured by electroretinogram. At the cellular level, we found that the EIU-associated rhodopsin decreased and the shortening of outer segments in photoreceptor cells were suppressed in the bilberry-extract-treated animals. Moreover, the extract prevented both STAT3 activation, which induces inflammation-related rhodopsin decrease, and the increase in interleukin-6 expression, which activates STAT3. In addition to its anti-inflammatory effect, the anthocyanin-rich bilberry extract ameliorated the intracellular elevation of reactive oxygen species and activated NF-κB, a redox-sensitive transcription factor, in the inflamed retina. Our findings indicate that anthocyanin-rich bilberry extract has a protective effect on visual function during retinal inflammation.