Blackcurrant Juice Research Articles

Physical and functional properties of spray-dried powders from blackcurrant juice and extracts obtained from the waste of juice processing.

Blackcurrants contain high levels of polyphenolics, particularly flavonols and anthocyanins, which contribute to their high antioxidant activity. The aims of this work were the recovery of bioactive compounds from the remaining solid (waste) after processing blackcurrant juice and to obtain spray-dried powders from the blackcurrant juice and extracts. The extraction of bioactive compounds from the fruit pulp was performed by ultrasound-assisted extraction. Experiments were conducted to select the more suitable solvent, and citric acid was chosen. Then, to optimize the extraction conditions (time, solvent concentration, and amplitude) an experimental design using a Box-Behnken Design was done. Comparing the optimized extract with the fruit, 31% total monomeric anthocyanins, 19% total phenolic compounds, and 10% antioxidant capacity were obtained. The optimized extract and the juice were mixed and spray dried, using maltodextrin as carrier matrix. A blackcurrant powder with low hygroscopicity 14.46 ± 0.13 (g a.w./100 g d.m) and high solubility 94.25 ± 4% was obtained. High concentration of bioactive compounds and antioxidant capacity was recorded: Total monomeric anthocyanins 63.01 ± 1 (mg cyn-3-glu/100 g.d.m), total phenolic content 116.87 ± 5 (mg gallic acid/100 g d.m.), and antioxidant capacity 144.40 ± 0.11 (mg eq Trolox/100 g.d.m.).

O35 An anthocyanin-rich blackcurrant extract induced NO-mediated relaxation in coronary artery rings and eNOS phosphorylation in cultured endothelial cells: Role of sodium-glucose cotransporters 1 and 2

Introduction The beneficial cardiovascular effect of polyphenol-rich food and beverages has been attributed, at least in part, to an improved vascular function through an increased endothelial formation of nitric oxide (NO) and endothelium-dependent hyperpolarization (EDH), two major vasoprotective mechanisms. Black currant is a rich source of anthocyanins, and, in particular, of glucoside- and rutinoside-conjugated delphinidin and cyanidin. This study evaluated the role of sodium-glucose cotransporters (SGLT) 1 and 2 in the blackcurrant extract (BCE)-induced NO-mediated endothelium-dependent relaxation and activation of endothelial NO synthase (eNOS). Methods The reactivity of porcine coronary artery rings was assessed in organ chambers, and the expression and phosphorylation level of proteins in cultured porcine coronary artery endothelial cells by Western blot analysis. Results BCE (310.0 ± 0.1 mg gallic acid equivalent/g) was prepared from a blackcurrant juice containing 2.7 g gallic acid equivalent/L of polyphenols using a Sephadex LH-20 column. BCE caused potent concentration-dependent relaxations of coronary artery rings with endothelium, which were significantly reduced by the dual SGLT1 and SGLT2 inhibitor LX4211, and also to some extent by the SGLT2 inhibitor canagliflozin but not dapagliflozin. In contrast, LX4211 did not affect relaxations to bradykinin, sodium nitroprusside and epigallocatechin gallate. BCE induced the phosphorylation of eNOS at the activator site Ser1177 in cultured endothelial cells, which was significantly prevented by LX4211, dapagliflozin and canagliflozin. Conclusion These observations indicate that BCE is a potent activator of eNOS and inducer of NO-mediated vasorelaxation possibly subsequent to the entry of conjugated anthocyanins via SGLT1/2 into endothelial cells.

Effect of mash enzyme and heat treatments on the cellular antioxidant activity of black currant (Ribes nigrum), raspberry (Rubus idaeus), and blueberry (Vaccinium myrtillus) juices

ABSTRACTThe aim of this study was to determine the effect of mash enzymatic maceration and heating treatments before pressing on the antioxidant activities in selected berry juices. Total phenolic contents were determined by the Folin–Ciocalteau assay, antioxidant activities were determined by means of the oxygen radical absorbance capacity (ORAC) assay, and the intracellular antioxidant potentials were determined through the cellular antioxidant activity (CAA) assay. Blueberry juices exhibited the highest antioxidant activity, followed by black currant and raspberry juices. The mash enzyme treatment with Pectinex® Ultra Color enzyme preparation, improved the antioxidant activities in vitro. ORAC values correlated with CAA values (R2 = 0.91) and a slightly positive correlation was observed between Folin–Ciocalteau and CAA assays (R2 = 0.56). The findings support the observation that the mash enzymatic treatment of macerated fruits enhances their antioxidant activity. Considering the chemical assays (ORAC and total phenolic content), a combined treatment with heating to 85°C followed by mash enzymatic treatment was the most effective. Considering a biological model through the CAA assay, however, a comparable improvement in antioxidant activity resulted from the enzymatic and the combined treatments. Overall, the data showed that maceration enzymatic treatment improves the intracellular antioxidant activity in HepG2 human cells. To the best of our knowledge, this is the first report on the effect of the antioxidant potential of mash enzymatic and heating treatments assessed by means of a cellular approach.

Effects of Juice Matrix and Pasteurization on Stability of Black Currant Anthocyanins during Storage.

The effects of juice matrix and pasteurization on the stability of total phenols and especially total and individual anthocyanins were examined in black currant (BC) juice and mixtures with apple, persimmon, and peach juices at 4 °C and 20 °C. Total phenol content decreased in all juices at both temperatures but there was a trend to lower levels in unpasteurized over pasteurized juices. Differences in the decline of total anthocyanins between pasteurized and unpasteurized juices varied according to the juice type and the storage temperature. At 4 °C storage, anthocyanins declined in all juices according to pseudo 1st-order kinetics and there were only small differences in the rates between pasteurized and unpasteurized juices. However, at 20 °C, although pasteurized and unpasteurized BC juices and pasteurized mixed juices followed pseudo 1st-order kinetics, there was a different pattern in unpasteurized mixed juices; a rapid initial decline was followed by a slowing down. The effect of the added juice on anthocyanin decline was also different at either temperature. At 4 °C, the anthocyanins decreased faster in mixed juices than BC juice alone, but at 20 °C, at least in pasteurized mixed juices, the decline was similar or even slower than in BC juice; there were only small differences among the 3 mixed juices. At 20 °C, in pasteurized and unpasteurized BC juices, the rate of decrease was essentially the same for all 4 individual anthocyanins but in the mixed juices the 2 glucosides decreased significantly faster than the 2 rutinosides.

Drink Red: Phenolic Composition of Red Fruit Juices and Their Sensorial Acceptance

Consumers’ food quality perception and sensorial experience are important in food consumption behavior and food choice. Red fruit juices are appreciated fruit juices for almost all consumers, due to their flavor and intense red color. Studies have also shown that their phytochemical composition, which is associated with their antioxidant activity, shows a protective effect against many chronic diseases. Nevertheless, the profile and concentration of anthocyanins are different in function of the fruit used; therefore, the color and health benefits of the juices also show differences. Some red fruit juices have lower concentrations of anthocyanins, for example strawberry, and others have higher concentrations, such as elderberry and black currant juices. High correlation was observed between antioxidant activity and red fruit juices’ total anthocyanins concentration. Therefore, this review will addresses red fruit juices phenolic composition, with a special focus on the challenges for future, and some ideas on the sensory impact.

Effect of processing technologies and storage conditions on stability of black currant juices with special focus on phenolic compounds and sensory properties.

Juice was pressed from black currants without enzyme treatment (NEB=Non-Enzymatic Berry) followed by re-pressing of the residue with enzymes (EPR=Enzymatic Press Residue) and the results were compared to the conventional enzyme-aided berry pressing (EB=Enzymatic Berry). EPR-juice had 9- and 5-fold higher contents of phenolic compounds compared with the NEB- and EB-juices, respectively. Effect of the low content and stability of phenolics was noticed as loss of the visual color in the NEB-juice during storage. The decrease in monomeric anthocyanins and the increase in phenolic acids were most severe in the NEB-juice, whereas the most significant decline in hydroxycinnamic acid derivatives occurred in the enzyme-treated juices. Storage in light induced less change in the phenolic composition in EPR-juice than in the two other juices. The study gave new knowledge on changes in individual metabolites, in sensory properties and in the shelf life of berry juices.

Detection of Blackcurrant Adulteration by Aronia Berry Using High Resolution Mass Spectrometry, Variable Selection and Combined PLS Regression Models

Aronia berry has a deep red colour, and as it is cheaper than blackcurrant, it may be used to adulterate blackcurrant juice and drinks made therefrom. The aim of the study was to produce a model using multivariate tools to quantify the level of adulteration of blackcurrant concentrates with aronia berry concentrates. Samples of various blends between the two fruits were analysed after dilution on an ultra high pressure liquid chromatography-time of flight mass spectrometry (UPLC-TOF-MS) to create partial least squares (PLS) models. Moreover, variable selection was investigated with the recursive weighted PLS (rPLS) method to increase PLS model quality, and different levels of fusion between data from the two ionisation modes were also compared. The best model was obtained from fusion of ionisation modes with variable selection using the rPLS method. The limit of detection of 5 % aronia berry concentrate in blackcurrant concentrate was achievable with ±1 % error on the adulteration level.

Hypotensive, cardiodepressant, and vasorelaxant activities of black currant (Ribes nigrum 'Ben Sarek') juice.

The aim of this study was to evaluate the effects of black currant (Ribes nigrum L. 'Ben Sarek') juice on the blood pressure and frequency of cardiac contractions, as well as vasomotor responses of rat aortic rings. Arterial blood pressure was measured directly from the carotid artery in the anaesthetized rabbits. The aortic rings were pre-contracted with KCl (80 mmol·L-1), after which black currant juice was added. An intravenous injection of black currant juice (0.33-166.5 mg·kg-1) induced a significant and dose-dependent decrease of rabbit arterial blood pressure and heart rate. The black currant juice decreased arterial blood pressure of rabbit by 22.33% ± 3.76% (p < 0.05) and heart rate by 17.18% ± 2.93% (p < 0.05). Cumulative addition of the black currant juice (0.01-3 mg·mL-1) inhibited concentration-dependent KCl induced contractions of the isolated rat aorta. The black currant juice, at the concentration of 3 mg·mL-1, caused a maximum relaxation of 21.75% ± 3.15% (p < 0.05). These results demonstrate that black currant juice can induce hypotension. The hypotensive effect of the black currant may occur as the consequence of its inhibitory activity on the rate of heart contraction and vasorelaxant effects.

Stability of Hydroxycinnamic Acid Derivatives, Flavonol Glycosides, and Anthocyanins in Black Currant Juice.

The stability of phenolic compounds was followed in black currant juice at ambient temperatures (in light and in dark conditions) and at +4 °C for a year. Analyses were based on high-performance liquid chromatography-diode-array detection-electrospray ionization-mass spectrometry (or tandem mass spectrometry) and high-performance liquid chromatography-diode-array detection-electrospray ionization-quadrupole time-of-flight mass spectrometry methods supported by nuclear magnetic resonance after selective high-performance liquid chromatography isolation. Altogether, 43 metabolites were identified, of which 2-(Z)-p-coumaroyloxymethylene-4-β-d-glucopyranosyloxy-2-(Z)-butenenitrile, 2-(E)-caffeoyloxymethylene-4-β-d-glucopyranosyloxy-2-(Z)-butenenitrile, 1-O-(Z)-p-coumaroyl-β-d-glucopyranose, (Z)-p-coumaric acid 4-O-β-d-glucopyranoside, and (Z)-p-coumaric acid were novel findings in black currant juice. Hydroxycinnamic acid derivatives degraded 20-40% at room temperature during one year of storage, releasing free hydroxycinnamic acids. O-Glucosides of hydroxycinnamic acid compounds were the most stable, followed by O-acylquinic acids, acyloxymethyleneglucosyloxybutenenitriles, and O-acylglucoses. Light induced the isomerization of (E)-coumaric acid compounds into corresponding Z-isomers. Flavonol glycosides stayed fairly stable. Flavonol aglycones were derived mainly from malonylglucosides. Over 90% of anthocyanins were lost at room temperature in a year, practically independent of light. Storage at low temperatures, preferably excluding light, is necessary to retain the original composition of phenolic compounds.

Black Currant (Ribes nigrum L.) and Bilberry (Vaccinium myrtillus L.) Fruit Juices Inhibit Adhesion of Asaia spp.

The aim of the study was to evaluate the activity of high-polyphenolic black currant (Ribes nigrum L.) and bilberry (Vaccinium myrtillus L.) juices against bacterial strains Asaia lannensis and Asaia bogorensis isolated as spoilage of commercial soft drinks. The composition of fruit juices was evaluated using chromatographic techniques HPLC and LC-MS. The adhesion to glass, polystyrene, and polyethylene terephthalate in two different culture media was evaluated by luminometry and the plate count method. The major anthocyanins in the V. myrtillus were petunidin-3-glucoside, malvidin-3-glucoside, cyanidin-3-glucoside, and delphinidin-3-glucoside, while in R. nigrum delphinidin-3-rutinoside and cyanidin-3-rutinoside were detected. The LC-MS analysis showed presence of anthocyanins (delphinidin, cyanidin, petunidin, and malvidin derivatives), phenolic acids (chlorogenic and neochlorogenic acids), flavonols (quercetin-3-glucoside, quercetin-3-rutinoside), and flavanols (procyanidin B2 and procyanidin type A2). Additionally, in the bilberry juice A type procyanidin trimer was detected. The adhesion of Asaia spp. cells depended on the type of medium, carbon sources, and the type of abiotic surfaces. We noted that the adhesion was significantly stronger in minimal medium containing sucrose. The addition of bilberry and black currant juices notably reduced bacterial growth as well as cell adhesion to polyethylene terephthalate surfaces.

Assessment of the Effect of Intestinal Permeability Probes (Lactulose And Mannitol) and Other Liquids on Digesta Residence Times in Various Segments of the Gut Determined by Wireless Motility Capsule: A Randomised Controlled Trial.

BackgroundWhilst the use of the mannitol/lactulose test for intestinal permeability has been long established it is not known whether the doses of these sugars modify transit time Similarly it is not known whether substances such as aspirin that are known to increase intestinal permeability to lactulose and mannitol and those such as ascorbic acid which are stated to be beneficial to gastrointestinal health also influence intestinal transit time.MethodsGastric and intestinal transit times were determined with a SmartPill following consumption of either a lactulose mannitol solution, a solution containing 600 mg aspirin, a solution containing 500 mg of ascorbic acid or an extract of blackcurrant, and compared by doubly repeated measures ANOVA with those following consumption of the same volume of a control in a cross-over study in six healthy female volunteers. The dominant frequencies of cyclic variations in gastric pressure recorded by the Smartpill were determined by fast Fourier transforms.ResultsThe gastric transit times of lactulose mannitol solutions, of aspirin solutions and of blackcurrant juice did not differ from those of the control. The gastric transit times of the ascorbic acid solutions were significantly shorter than those of the other solutions. There were no significant differences between the various solutions either in the total small intestinal or colonic transit times. The intraluminal pHs during the initial quartiles of the small intestinal transit times were lower than those in the succeeding quartiles. This pattern did not vary with the solution that was consumed. The power of the frequencies of cyclic variation in intragastric pressure recorded by the Smartpill declined exponentially with increase in frequency and did not peak at the reported physiological frequencies of gastric contractile activity.ConclusionsWhilst the segmental residence times were broadly similar to those using other methods, the high degree of variation between subjects generally precluded the identification of all but gross variation between treatments. The lack of any differences between treatments in either total small or large intestinal transit times indicates that the solutions administered in the lactulose mannitol test of permeability had no consistent influence on the temporal pattern of absorption. The negatively exponential profile and lack of any peaks in the frequency spectra of cyclic variation in gastric intraluminal pressure that were consistent with reported physiological frequencies of contractile activity profile suggests that the principal source of this variation is stochastic likely resulting from the effects of external events occasioned by normal daily activities on intra-abdominal pressure.Trial RegistrationAustralian New Zealand Clinical Trials Registry ACTRN12615000596505

Delphinidin-3-O-glucoside and delphinidin-3-O-rutinoside mediate the redox-sensitive caspase 3-related pro-apoptotic effect of blackcurrant juice on leukaemia Jurkat cells

Blackcurrant, a rich source of anthocyanins, has been reported to exhibit an antiproliferative effect on several types of solid tumour cancer cells, but its active molecules and the precise mechanism of their action remain unclear. The aim of the present study was to investigate the anticancer effect of blackcurrant-derived products (juice (BCJ), extract (BCE) and anthocyanins, namely cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside, delphinidin-3-O-glucoside and delphinidin-3-O-rutinoside) in Jurkat cells and to characterize the underlying mechanism. Cell cycle and apoptosis were assessed by flow cytometry, the formation of reactive oxygen species (ROS) by dihydroethidine and protein expression by Western blotting. BCJ and BCE inhibited the proliferation and induced G2/M phase cell cycle arrest and apoptosis in Jurkat cells associated with an increased expression of p73 and caspase 3, dephosphorylation of Akt and Bad, and down-regulation of UHRF1 and Bcl-2. A pro-apoptotic response was also observed in response to two major blackcurrant anthocyanins, delphinidin-3-O-rutinoside and delphinidin-3-O-glucoside. The BCJ- and BCE-induced activation of caspase 3 was markedly inhibited by pretreatment with N-acetylcysteine. BCE and the two active anthocyanins induced the formation of reactive oxygen species. BCJ and its major anthocyanins induced a redox-sensitive caspase 3-dependent apoptosis in Jurkat cells, involving a dysregulation of the Akt/Bad/Bcl-2 pathway.

Proanthocyanidins and Their Contribution to Sensory Attributes of Black Currant Juices.

Black currant juices from five different cultivars were analyzed for composition, content, and mean degree of polymerization (mDP) of proanthocyanidins (PA) by UPLC-MS/MS. Juices contained both procyanidins (PC) and prodelphinidins (PD), but the PC-% varied significantly, from 28 to 82% of the total PA. In addition, high PD-% was related to high mDP and total PA content. Enzyme-assisted processing increased significantly total PA (5-14-fold), PD-% (12-65%), and mDP (1.8-6.2-fold) in the juices of all cultivars. Enzymatic treatment increased the contents of large PAs more than those of small PAs. The contents of PA and mDP were positively associated with the mouth-drying and puckering astringent characteristics. However, the PA content did not contribute to the bitter taste. Juices from the most bitter cultivars had the lowest contents of proanthocyanidins regardless of the processing method. This finding indicates the existence of other bitter compounds in black currants in addition to PA.

Phenolic Profile and Antioxidant Activity of Polish Meads

The purpose of this study was to evaluate phenolic profile and antioxidant activity of ten different meads of 1:1 and 1:2 types, produced with addition of fruit juices, root spices, and herbs. The total phenolic content in meads varied from 15.27 to 70.80 mg/dm3. The meads originated from dark honeys exhibited the highest antioxidant activity. The predominant phenolic compounds in meads were hydroxybenzoic acids, especially gallic and protocatechuic acid, originated mainly from honeys. Whereas, among the hydroxycinnamic acids, the major phenolic was chlorogenic acid, derived mainly from plant additives used in meads production. A principal component analysis was applied in order to differentiate the investigated meads. The 1:2 meads type could be best described by chlorogenic acid. Among the 1:1 meads type, those made from the dark honeys could be best described by gallic, p-coumaric, and protocatechuic acid while those made with addition of blackcurrant and raspberry juice could be described by caffeic and ferulic acid.

A Randomised trial to investigate the erosive effect of hot drinks.

Research on dental erosion has largely been undertaken at room temperature despite fruit juice drinks often being consumed at elevated temperatures in the United Kingdom, notably during periods of convalesce. The aim of the study was to evaluate the erosive potential of two fruit juices containing acidic non-alcoholic drinks at elevated temperatures insitu on human enamel after 5, 10 and 15days. A commercially available conventional apple and blackcurrant fruit juice drink was compared to a blackcurrant juice drink modified to have low erosive potential, and mineral water consumed at approximately 59°C. Twenty-one healthy volunteers aged 18 or over participated in a single-centre, single-blind (blinded to the investigator), three-treatment crossover study. Subjects were randomised to a treatment sequence using a Latin square design. Subjects wore upper removable appliances containing one human enamel specimen from 9 am to 5pm for 15days for each beverage. Measurements of enamel loss were recorded after 5, 10 and 15days by contact surface profilometry. The low erosive blackcurrant drink caused significantly less enamel loss (P<0·05) than the commercially available conventional apple and blackcurrant fruit juice drink and was not statistically significantly different to mineral water at any of the time points in the study. Consuming the modified low erosive blackcurrant drink at an elevated temperature resulted in negligible enamel loss insitu, consistent with room temperature findings.

Antibacterial activity of berry juices, an in vitro study

Objective. The aim of the present study was to evaluate in vitro antibacterial activities of blackcurrant and sea buckthorn juices on bacteria associated with gingival inflammation. Materials and methods. The growth of selected bacteria (Streptococcus mitis, Streptococcus mutans, Streptococcus sanguinis, Streptococcus gordonii, Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa) was studied in vitro on agar plates. The content of phenols in the different extracts was measured with HPLC-ESI-MS. Results. The spectrometric analysis identified that the highest level of the single phenols studied was found for ferulic acid (113 μg/ml) in blackcurrant juice. Sea buckthorn contained low levels of selected phenols. Total bacterial inhibition for all bacterial species studied was found at 20% berry juice concentration with pH varying between 4.1–5.4. Conclusions. The present study identified that in vitro bacterial growth on agar plates was inhibited by blackcurrant and sea buckthorn juices and that low juice pH explains bacterial in vitro growth. This may have clinical implications in biofilm development, reducing the risks for both tooth decay and gingivitis.

Antiproliferative and antioxidant properties of anthocyanin rich extracts from blueberry and blackcurrant juice.

The present study was aimed at evaluating the antiproliferative potential of anthocyanin-rich fractions (ARFs) obtained from two commercially available juices (blueberry and blackcurrant juices) on three tumor cell lines; B16F10 (murine melanoma), A2780 (ovarian cancer) and HeLa (cervical cancer). Individual anthocyanin determination, identification and quantification were done using HPLC-MS. Antioxidant activity of the juices was determined through different mechanism methods such as DPPH and ORAC. For biological testing, the juices were purified through C18 cartridges in order to obtain fractions rich in anthocyanins. The major anthocyanins identified were glycosylated cyanidin derivatives. The antiproliferative activity of the fractions was tested using the MTT assay. The antiproliferative potential of ARF was found to be associated with those bioactive molecules, anthocyanins due to their antioxidant potential. The results obtained indicated that both blueberry and blackcurrants are rich sources of antioxidants including anthocyanins and therefore these fruits are highly recommended for daily consumption to prevent numerous degenerative diseases.

Great heterogeneity of commercial fruit juices to induce endothelium-dependent relaxations in isolated porcine coronary arteries: role of the phenolic content and composition.

Since polyphenol-rich products such as red wine, grape juice, and grape extracts have been shown to induce potent endothelium-dependent relaxations, we have evaluated whether commercial fruit juices such as those from berries are also able to induce endothelium-dependent relaxations of isolated coronary arteries and, if so, to determine whether this effect is related to their phenolic content. Among the 51 fruit juices tested, 2/12 grape juices, 3/7 blackcurrant juices, 4/5 cranberry juices, 1/6 apple juices, 0/5 orange juices, 2/6 red fruit and berry juices, 3/6 blends of red fruit juices, and 0/4 non-red fruit juices were able to induce relaxations achieving more than 50% at a volume of 1%. The active fruit juices had phenolic contents ranging from 0.31 to 1.86 g GAE/L, which were similar to those of most of the less active juices with the exception of one active grape juice (2.14 g GAE/L) and one active blend of red fruit juices (3.48 g GAE/L). Altogether, these findings indicate that very few commercial fruit juices have the ability to induce potent endothelium-dependent relaxations, and that this effect is not related to their quantitative phenolic content, but rather to their qualitative phenolic composition.

Sensitive Voltammetric Determination of Natural Flavonoid Quercetin on a Disposable Graphite Lead.

In this paper, a pencil graphite electrode was pretreated using chronoamperometry technique in phosphate buffer solution (pH=7.0) for sensitive determination of quercetin. Oxidation of quercetin was investigated using pretreated pencil graphite electrode and anodic stripping differential pulse voltammetry. Under optimal conditions, the anodic current of quercetin exhibited linear response to its concentration in the range from 0.001 to 1.5 µmol/L with the limit of detection of 0.3·10-3 µmol/L. The proposed method was successfully applied for the determination of quercetin in cranberry and blackcurrant juices with recovery rate from 93.2 to 94.7%. Solid-phase extraction was found to be necessary prior to voltammetric determination of quercetin in fruit juice samples using pretreated pencil graphite electrode.

Beetroot supplementation lowers daily systolic blood pressure in older, overweight subjects

Although inorganic nitrate and beetroot juice supplementation are associated with decreased systolic blood pressure (BP), these results have primarily been obtained from short-term trials that focused on healthy young adults. Therefore, we hypothesized that oral supplementation of beetroot juice concentrate would decrease systolic BP in overweight older participants but that the decline in BP would not be sustained after a 1-week interruption of the beetroot juice supplementation. For 3 weeks, 24 participants were randomized to either the beetroot juice concentrate or blackcurrant juice group, with a 1-week postsupplementation phase (week 4). Changes in systolic and diastolic BP were assessed during the supplementation and postsupplementation phases. Blood pressure was measured using 3 different methods: (1) resting clinic BP, (2) 24-hour ambulatory BP monitoring, and (3) home monitoring of daily resting BP. The first 2 methods were applied at baseline and after weeks 3 and 4. Daily measurements were conducted throughout the study, with 21 subjects completing the study (beetroot/blackcurrant = 10/11; male/female = 12/9; age = 62.0 ± 1.4 years; body mass index = 30.1 ± 1.2 kg/m2). After 3 weeks, beetroot juice supplementation was not associated with significant changes in resting clinic BP or 24-hour ABPM. Conversely, beetroot juice concentrate reduced daily systolic BP after 3 weeks (−7.3 ± 5.9 mm Hg, P = .02); however, the effect was not maintained after the interruption of the supplementation (week 4, 2.8 ± 6.1 mm Hg, P = .09). In overweight older subjects, beetroot juice concentrate supplementation was associated with beneficial effects on daily systolic BP, although the effects were not significant when measured by 24-hour ABPM or resting clinic BP.