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1.
The formation of anthocyanin–metal chelates, exhibiting intense blue colours was monitored over a period up to 10 weeks. Evaluating normalised absorption spectra in the range of 580–700 nm and their proportion of the total area under the curve (AUC), provided information about the blue colour hue, intensity and stability. Colour stability in model solutions containing commercial sugar beet pectin or an isolated pectic polysaccharide fraction (PPF) therefrom, both being naturally enriched in aluminium and ferric ions, was assessed in a pH range of 3.6–7.0. The pectic structures stabilised anthocyanin–metal chelates, and thus blue colours by efficiently preventing complex precipitation. Highest bathochromic shifts and most intense blue colours were observed in PPF model solutions containing delphinidin-3-glucoside (Dpd-3-glc), exhibiting a pyrogallol moiety in the flavylium B-ring, compared to cyanidin- (Cyd-3-glc) and petunidin-3-glucoside (Pet-3-glc), both carrying a catechol substituted B-ring. Hue and intensity of the blue colour at pH 5.0 were only insignificantly influenced by the buffer system except for citrate and phosphate buffers, which both annihilated anthocyanin–metal chelate formation. The blue colours faded following first order kinetics. Best stabilities as deduced from storage experiments performed at 20 ± 2 °C in the dark were observed for Dpd-3-glc. In contrast, Cyd-3-glc displayed shortened half-life values, whereas blue Pet-3-glc chelates decomposed rapidly. These results demonstrate that the solubilisation of anthocyanin–metal chelates by pectic structures is a promising option for developing water soluble natural blue food colourants.  相似文献   

2.
Reverse osmosis process for the concentration of black currant juice was carried using AFC-99 tubular membrane at 30 °C and 45 bar. The contents of selected flavonols and anthocyanins were analyzed after centrifugation; enzyme treatment by Panzym Super E and by Rohapect berry followed by centrifugation; and ultrafiltration black currant juices and juice concentrates. The total soluble solid (TSS) content of the juices increased from the initial 17.6–17.9 °Brix to 24–24.8 °Brix in the case of the centrifuged juice in the concentration process. Similarly, it increased from 14.5–15.5 °Brix to 23.1–23.4 °Brix for the Panzym Super E treated juice, and from 16.1–16.9 °Brix to 22.5–23.1 °Brix for the Rohapect berry treated black currant juices. The ultrafiltered juice had the lowest initial TSS content between 14.1 and 14.9 °Brix and it increased to 22.1–23.1 °Brix. The average permeate fluxes during the concentration process were 7.3 L m−2 h−1 for the centrifuged juice, 11.9 L m−2 h−1 for the Panzym Super E treated juice, 9.2 and 13.1 L m−2 h−1 for the Rohapect berry treated and ultrafiltered juice, respectively. Analysis indicated that the enzymatic treatment resulted in the increase of anthocyanin and flavonol content of the juices. The centrifugation process decreased the amount of anthocyanins and flavonols to some extent. The juice clarified by ultrafiltration had significantly lower concentrations of anthocyanins and flavonols, while the juices treated by Panzym Super E had the highest levels of these flavonoids. This study recommends enzymatic pre-treatment by Panzym Super E, since it improves the permeate flux in reverse osmosis during the concentration process, and results in a juice concentrates highest in anthocyanins and flavonols.  相似文献   

3.
Anthocyanin-rich beverages have shown beneficial effects on coronary heart disease in epidemiological and intervention studies. In the present study, we investigated the effect of black currant anthocyanins on atherosclerosis. Watanabe Heritable Hyperlipidemic rabbits (n = 61) were fed either a purified anthocyanin fraction from black currants, a black currant juice, probucol or control diet for 16 weeks. Purified anthocyanins significantly increased plasma cholesterol and low-density lipoprotein (LDL) cholesterol. Intake of black currant juice had no effect on total plasma cholesterol, but lowered very-low-density lipoprotein (VLDL) cholesterol significantly. There were no significant effects of either purified anthocyanins or black currant juice on aortic cholesterol or development of atherosclerosis after 16 weeks. Probucol had no effect on plasma cholesterol but significantly lowered VLDL-cholesterol and decreased aortic cholesterol accumulation. The erythrocyte antioxidant enzyme glutathione peroxidase was significantly increased by purified anthocyanins and superoxide dismutase was increased by both anthocyanin-containing treatments. Other markers of plasma antioxidant capacity, antioxidant enzymes, protein and lipid oxidation were not affected by any of the anthocyanin treatments. Adverse effects of purified anthocyanins were observed on plasma- and LDL-cholesterol. These effects were not observed with black currant juice, suggesting that black currants may contain components reducing the adverse effects of anthocyanins.  相似文献   

4.
Fruit juices (apple, grape, orange, grapefruit, tangerine and lemon) and nectars (apricot, peach and pineapple) were coloured with black carrot juice concentrate and stability of black carrot anthocyanins in these matrices was studied during heating at 70–90 °C and storage at 4–37 °C. Anthocyanin degradation, in all coloured juices and nectars, followed first-order reaction kinetics. During heating, black carrot anthocyanins in apple and grape juices showed higher stability than those in citrus juices at 70 and 80 °C. High stability was also obtained for the anthocyanins in peach and apricot nectars at these temperatures. Black carrot anthocyanins were the least stable in orange juice during both heating and storage. During storage, degradation of anthocyanins was very fast at 37 °C, especially in pineapple nectar. Refrigerated storage (4 °C) markedly increased the stability in all samples. Activation energies for the degradation of black carrot anthocyanins in coloured juices and nectars ranged from 42.1 to 75.8 kJ mol−1 at 70–90 °C and 65.9–94.7 kJ mol−1 at 4–37 °C.  相似文献   

5.
Total phenolics, total anthocyanins, mineral content, radical scavenging activity and antiproliferative activity against human cancer cell lines were evaluated in fresh pressed juices of five different berries. Total phenolic content ranged from 133.0 to 260.3 mg of gallic acid equivalents/100 g of fresh weight, for red currant and black currant, respectively. Bilberry juice contained the highest amount of total anthocyanins (0.18%). Significant correlation between total phenolics content and radical scavenging activity was observed (r = −0.980; p < 0.01). All examined juices showed antiproliferative activity in dose-dependent manner with IC50 ranging from 10.2 to 70.5 μl/ml. Black currant juice was the most effective inhibitor of proliferation in all cell lines tested (HeLa, Fem X, LS 174, MCF-7 and PC-3). Significant correlations of acidity and total anthocyanin content with antiproliferative activity of berry juices on HeLa cells, Fem X cells and MCF-7 cells were noticed. Berry juices are good sources of some minerals and contribute significantly to daily intake of these micronutrients.  相似文献   

6.
Roots of three unique Chinese radish cultivars were evaluated as potential sources for anthocyanin-type colourants or value-added products. These cultivars showed high variation in anthocyanins (63.77–160.74 mg/100 g FW). Seventeen pigments were tentatively identified by mass spectroscopy as pelargonidin-3-sophoroside-5-glucoside derivatives with multiple acylation of hydroxycinnamic acids. A bright colour (CIELab) of radish anthocyanins has been shown at a wide pH range, comparably stable at pH < 4.2. Those anthocyanins also showed a remarkable thermal stability, following a zero-order kinetics at pH 2.5 with half-lives of 14.5 or 8.7 h at 90 or 100 °C, respectively. Additionally, those cultivars varied in glucosinolate contents (59.69–163.91 mg/100 g FW), whereas their degradation was sensitive to pH and followed a first-order kinetics at pH 5.8 with half-lives of 11.44 or 7.05 h at 90 or100 °C, respectively. However, the stable pH ranges for anthocyanins and glucosinolates were different: pH < 4.2 and pH > 3.6, respectively. In a radish juice model (pH 5.8/2.5), thermal degradation of anthocyanins or glucosinolates was associated closely with media pH values. In conclusion, cultivar selection, and thermal and pH conditions during processing or storage should be taken into account for quality, stability, and health benefits of radish derived natural colourants or nutraceutical products.  相似文献   

7.
Anthocyanin stability of black carrots was studied at various solid contents (11, 30, 45 and 64° Brix) and pHs (4.3 and 6.0) during both heating, at 70–90 °C, and storage at 4–37 °C. Monomeric anthocyanin degradation fitted a first-order reaction model. Degradation of monomeric anthocyanins increased with increasing solid content during heating, while it decreased during storage. For example, at pH 4.3, half-life periods for anthocyanins at 30, 45 and 64° Brix were, respectively, 8.4, 6.9 and 5.2 h during heating at 80 °C and 18.7, 30.8 and 35.9 weeks during storage at 20 °C. At 30–64° Brix, increasing pH from 4.3 to 6.0 enhanced the degradation of anthocyanins during heating. The effect of pH on thermal stability of anthocyanins was also studied at six different pHs (2.5–7.0) in citrate-phosphate buffer solutions and significant decrease in anthocyanin stability was observed at pHs above 5.0. Higher activation energies (Ea) were obtained during heating than during storage with increasing solid contents. At 30–64° Brix, Ea values ranged from 68.8 to 95.1 kJ mol−1 during heating and from 62.1 to 86.2 kJ mol−1 during storage. Q10 values at 20–37 °C were as high as 3.1 at 45° Brix and 3.6 at 64° Brix.  相似文献   

8.
Bilberries (Vaccinium myrtillus L.) and black currants (Ribes nigrum L.), dark blue berries rich in anthocyanins, were processed with an aid of commercial pectinolytic enzyme preparations, and the effect of processing on berry anthocyanins was investigated. The enzyme preparations were dosed based on their polygalacturonase activity from 1 to 100 nkat/g of berry mash. The juice yields were determined by weighing, and anthocyanin analyses were performed with HPLC. The bilberry and black currant juice yields increased significantly in enzyme-aided treatments with comparison to control, even with the lowest (1 nkat/g) polygalacturonase dosage. The anthocyanin yield increased by up to 83% for bilberries and up to 58% for black currants in enzyme-aided treatments as compared to control. The results showed that higher polygalacturonase dosage was needed for black currant to achieve the maximal juice and anthocyanin yields than for bilberries. The stability and the profile of extracted anthocyanins were greatly affected by the glycosidase side activities present in the enzyme preparations, which were able to hydrolyze certain anthocyanins to the corresponding aglycones. In addition, the data indicate that anthocyanidin rutinosides were more easily extracted than those of glucosides, which prevailed over the arabinosides and galactosides. Thus, prior to processing it is important to know the intact anthocyanin structures of the raw material, and the activity profile of the enzyme preparation to obtain optimal anthocyanin extractability and enzyme dosage.  相似文献   

9.
Edible coatings as chitosan treatments (0%, 1% and 2%) were applied to ‘Rabbab-e-Neyriz’ pomegranate (Punica granatum L.). The effect of chitosan coating on individual anthocyanins and colour parameters of the juice during storage at 2 °C or 5 °C was examined. Six predominant anthocyanins were identified in the juice, with up to 935 mg/L total anthocyanins at the time of harvest. Cyanidin 3,5-diglucoside (402 mg/L) was the major pigment. The total anthocyanin content and chroma decreased with storage time in all applied treatments, although lightness and hue angle increased. These changes were reduced with chitosan treatments and at lower storage temperature (2 °C as compared to 5 °C). Based on the obtained results, the diglucoside anthocyanins were more stable than the monoglucosides. Chitosan coating followed by cold storage delayed anthocyanin degradation and prevented colour deterioration in the pomegranate arils.  相似文献   

10.
The influence of different classes of naturally occurring and externally added polyphenolic cofactors on the phytochemical and colour stability of anthocyanins in açai fruit (Euterpe oleracea) was investigated. Model systems were based on anthocyanin isolates from açai fruit, rich in cyanidin-3-rutinoside (311 ± 27 mg/l) and cyanidin-3-glucoside (208 ± 18 mg/l), and isolated groups of naturally occurring polyphenolic cofactors in açai fruit (phenolic acids, procyanidins, and flavone-C-glycosides, each adjusted to ∼50 mg/l). Anthocyanin degradation kinetics were assessed as a function of pH (3.0, 3.5, and 4.0) and storage temperature (5, 20 and 30 °C). During storage, anthocyanins experienced pH and temperature-dependent losses, and the half life cyanidin-3-rutinoside (t1/2 = 2.67–210 days) was consistently longer than cyanidin-3-glucoside (t1/2 = 1.13–144 days). The presence of flavone-C-glycosides induced significant hyperchromic shifts and enhanced anthocyanin stability at all pH and temperature combinations, while no significant effects were attributed to the presence of phenolic acids or procyanidins. Additional models using externally added cofactors from rooibos tea, also rich in flavone-C-glycosides, resulted in up to 45.5% higher anthocyanin colour and up to 40.7% increased anthocyanin stability compared to uncopigmented anthocyanin isolates and had similar copigmentation effects to a commercial rosemary-based colour enhancer. Results suggest flavone-C-glycosides offer potential for their use as colour enhancers and stabilizing agents in products rich in cyanidin glycosides, particularly açai fruit-containing foods, juice blends, and beverages.  相似文献   

11.
The effects of pH, storage period, temperature, light and dark conditions on the stability of anthocyanins extracted from Tibouchina semidecandra flowers of different developmental stages was evaluated. Fully formed but unopened flower bud had the highest amount of total anthocyanin extracted from fresh petals. The anthocyanin contents for all flower developmental stages were stable at pH 0.5–3.0 but the colour of the extracts faded at higher pH values. Degradation percentages of total anthocyanins in the extracts kept at 25 °C were 7–20% lower than that maintained at 31 °C. Extracts stored in darkness at 25 °C maintained their purple colour for 26 days while light exposure reduced it to an average of 10 days. The study shows that suitable storage condition for coloured anthocyanin pigments in extracted form is in acidic conditions in the dark. This implies the potential usage of coloured anthocyanins as natural food colourants and shelf life indicator for acidic foods.  相似文献   

12.
The aim of this study was to determine the usability of fruits of selected species growing in Europe for the smoothies production. The organoleptic assessment, analysis of polyphenols and vitamin C content and antioxidant activity of products were determined. The panellists were most in favour of the smoothies containing cranberry, black currant and bilberry purees as well as juice from dog rose. Polymerised proanthocyanidins were found to predominate in most of the products, except for the black currant smoothies (B3) where the main group of polyphenols were anthocyanins. The content of proanthocyanidins was higher in the smoothies containing dog rose juice. The analysed products differed significantly in the content of vitamin C, as the highest content of ascorbic acid was determined in black currant smoothies with dog rose juice and bilberry puree (168.98 mg/100 g).  相似文献   

13.
The effects of electrical stimulation (90 V) 20 min post mortem on meat quality and muscle fibre types of four age group camels (1–3, 4–6, 7–9, 10–12 years) camels were assessed. Quality of the Longissimus thoracis at 1 and 7 days post mortem ageing was evaluated using shear force, pH, sarcomere length, myofibrillar fragmentation index, expressed juice, cooking loss and L, a, b colour values. Age of camel and electrical stimulation had a significant effect on meat quality of L. thoracis. Electrical stimulation resulted in a significantly (P < 0.05) more rapid pH fall in muscle during the first 24 h after slaughter. Muscles from electrically-stimulated carcasses had significantly (P < 0.05) lower pH values, longer sarcomeres, lower shear force value, higher expressed juice and myofibrillar fragmentation index than those from non-stimulated ones. Electrically-stimulated meat was significantly (P < 0.05) lighter in colour than non-stimulated based on L value. Muscles of 1–3 year camels had a significantly (P < 0.05) lower shear force value, and pH, but longer sarcomere, and higher myofibrillar fragmentation index, expressed juice, and lightness colour (L) than those of the 10–12 years camels. The proportions of Type I, Type IIA and Type IIB were 25.0, 41.1 and 33.6%, respectively were found in camel meat. Muscle samples from 1–3 year camels had significantly (P < 0.05) higher Type I and lower Type IIB fibres compared to those from 10–12 year camel samples. These results indicated that age and ES had a significant effect on camel meat quality.  相似文献   

14.
The influence of temperature (10–45 °C), feed flow rate (300–500 L/h) and sweeping gas flow rate (1.2–2 m3/h) on the recovery of berry fruit juice aroma compounds by sweeping gas membrane distillation (SGMD) was examined on an aroma model solution and on black currant juice in a lab scale membrane distillation set up. The data were compared to recovery of the aroma compounds by vacuum membrane distillation (VMD). The flux of SGMD increased with an increase in temperature, feed flow rate or sweeping gas flow rate. Increased temperature and feed flow rate also increased the concentration factors (Cpermeate/Cfeed) of the aroma compounds. At 45 °C the most volatile and hydrophobic aroma compounds obtained the highest concentration factors: 12.1–9.3 (black currant juice) and 17.2–12.8 (model solution). With black currant juice a volume reduction of 13.7% (vol.%) at 45 °C, 400 L/h, resulted in an aroma recovery of 73–84 vol.% for the most volatile compounds. Compared to VMD, the aroma recovery with SGMD was less influenced by the feed flow rate but more influenced by the temperature. Higher fluxes were achieved during concentration by VMD and this reduced the operation time, which in turn reduced the degradation of anthocyanins and polyphenolic compounds in the juice.

Industrial relevance

High temperature evaporation is the most widely used industrial technique for aroma recovery and concentration of juices, but membrane distillation (MD) may provide for gentler aroma stripping and lower energy consumption. This study gives important clues about the fate of berry juice aroma compounds and polyphenols during concentration by MD, and identifies the main factors influencing the aroma recovery efficiency with MD. Both SGMD and VMD are promising techniques for gentle stripping of berry juice aroma compounds and deserve further consideration as alternative techniques for gentle aroma stripping in industrial fruit juice processing.  相似文献   

15.
The freeze-dried sprouts’ juice of Raphanus sativus (L.) cv. Sango was prepared and analysed for the first time. HPLC analysis of total isothiocyanates, after protein displacement, resulted in 77.8 ± 3.0 μmol/g of dry juice while GC–MS analysis of hexane and acetone extracts showed E- and Z-raphasatin (8.9 and 0.11 μmol/g, respectively) and sulforaphene (11.7 μmol/g), summing up to 20.7 ± 1.7 μmol/g of free isothiocyanates. Sprouts’ juice contained an unprecedented wealth of anthocyanins and a new fractionation methodology allowed us to isolate 34 mg/g of acylated anthocyanins (28.3 ± 1.9 μmol/g), belonging selectively to the cyanidin family. Analysis was performed by HPLC–PDA–ESI–MSn and extended to deacylated anthocyanins and aglycones, obtained, respectively, by alkaline and acid hydrolysis. This study identified 70 anthocyanins, 19 of which have never been described before and 32 of which are reported here in R. sativus for the first time. Sango radish sprouts are exceptional dietary sources of heath-promoting micronutrients.  相似文献   

16.
ABSTRACT: Processing of black currant juice includes crushing, heating, enzyme treatment, pressing, pasteurization, clarification, and filtration. Changes in concentration of impact aroma compounds and anthocyanins during black currant juice processing in pilot plant scale were examined. Impact compounds were identified by gas chromatography-olfactometry and quantified by dynamic headspace and gas chromatography-mass spectrometer. Anthocyanins were analyzed by the pH-differential method. Identified aroma compounds comprised volatiles like esters, terpenes, terpenoids, and ketones. The reduction of aroma compounds and anthocyanins during the process was approximately 50 to 100% and 25%, respectively. The pressing step definitely had a negative effect on the concentration of aroma compounds and anthocyanins, and the heating treatments were mainly negative as well.  相似文献   

17.
A novel chitinase was isolated and purified to its homogeneity from pomegranate juice by a combination of ammonium sulphate precipitation and ion-exchange chromatography. The pomegranate juice chitinase (PJC) was purified to specific activity of 14.5 U/mg and a recovery of 34%. The monomeric protein migrated on SDS–PAGE at 29 kDa. The enzyme was found to be glycosylated (7.2%). It exhibited optimal activity at pH 4.5 and 70 °C. The enzyme was stable in the pH range 3.0–9.0 and up to 65 °C. The internal peptide sequence results suggest that the purified PJC shared high homology with class III chitinases of other known plant chitinases. The purified enzyme could hydrolyse colloidal chitin to its oligomers. It did not exhibit any antifungal activity.  相似文献   

18.
Solid-phase extraction (SPE) was used to obtain anthocyanin-rich extracts from five berry species: chokeberry, elderberry, black currant, blackberry and blueberry. During SPE more than 94.4% of the sugars and more than 88.5% of the acids present in the crude extracts were separated. The SPE resulted in 90–95.6% anthocyanins recovery. The antioxidative properties of the anthocyanin-rich extracts were tested by measuring their oxygen radical absorption capacity (ORAC), hydroxyl radical averting capacity (HORAC), total peroxyl radical trapping antioxidant parameter (TRAP), scavenging of nitric oxide and inhibition of lipid peroxidation. Elderberry extract revealed the highest ORAC value of 5783 μmol TE/g. Chokeberry extract was the most potent inhibitor of lipid peroxidation and had the highest TRAP value of 4051 μmol TE/g. Blueberry extract had the highest HORAC result – 1293 μmol GAE/g and was the most powerful scavenger of NO. The high antioxidant activity according to all antioxidant assays revealed opportunities to apply these preparations as antioxidants.  相似文献   

19.
The effect of temperature on the degradation of blackcurrant anthocyanins in a model juice system was determined over a temperature range of 4–140 °C. The thermal degradation of anthocyanins followed pseudo first-order kinetics. From 4–100 °C an isothermal method was used to determine the kinetic parameters. In order to mimic the temperature profile in retort systems, a non-isothermal method was applied to determine the kinetic parameters in the model juice over the temperature range 110–140 °C. The results from both isothermal and non-isothermal methods fit well together, indicating that the non-isothermal procedure is a reliable mathematical method to determine the kinetics of anthocyanin degradation. The reaction rate constant (k) increased from 0.16 (±0.01) × 10−3 to 9.954 (±0.004) h−1 at 4 and 140 °C, respectively. The temperature dependence of the rate of anthocyanin degradation was modelled by an extension of the Arrhenius equation, which showed a linear increase in the activation energy with temperature.  相似文献   

20.
Pre-press maceration treatments with 10 different pectinolytic enzyme preparations were investigated in experimental black currant juice production using response surface design templates. Enzyme dosage, maceration time, reaction temperature, and degree of berry crushing were varied, and the juice yields, anthocyanins, total phenols, and turbidity in the resulting juices were compared for a total of 250 different enzymatic treatments. The yields of anthocyanins and total phenols in the juices ranged from 900 to 2200 and 3050 to 5100 mg/kg wet weight black currant mash, respectively. Juice yields ranged from 66.4% to 78.9% by wet weight of mash. Turbidity levels ranged from 25 to 916 formazan nephelometric units (FNU). The reaction parameters induced larger variations in the responses than the different enzyme preparations, but the cloned Aspergillus niger/Aspergillus aculeatus preparation Pectinex BE® consistently tended to be among those giving the best responses regarding anthocyanin yields, phenols, and low juice turbidity. The optimal maceration was achieved using an enzyme dosage of 0.18% by wet weight of berries with a reaction at 60 °C for 30 min on the most finely crushed berry mash. This treatment gave similar profiles of anthocyanins in the juices with all the 10 enzyme preparations. The same 10 juices all exhibited antioxidant activity against human low-density lipoprotein oxidation in vitro, but the antioxidant potency varied depending on the enzyme preparation used in the pre-press maceration.  相似文献   

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