Monomeric Anthocyanin Degradation Research Articles

Simplified process of extraction of polyphenols from agroindustrial grape waste

Abstract The extraction, and stability of polyphenols from the grape residue were studied. The extractions were performed following the Box-Behnken design, and the surface response methodology was used to model the extraction of total anthocyanins (TA), flavonols (TF), and phenolics (TP). The extraction was optimized simultaneously by the desirability function. The degradation kinetics of monomeric anthocyanins, and the increase in polymeric color were modeled under refrigeration conditions. The extraction with a temperature of 60 °C, solid:liquid ratio of 1/25 g/mL, and time of 80 min, maximized the recovery of TA (30.96 mg/100 g), TF (73.34 mg/100 g), and TP (856.78 mg EAG/100 g). The degradation of monomeric anthocyanins, and the increase in polymeric color followed a kinetic first-order reaction, with reaction rates (k) of 4.10 x 10-3 days-1, and 3.46 x 10-3 days-1, respectively. The half-life (t1/2) of anthocyanins was 169 days. The ethanol-citric acid solution allowed polyphenols to be efficiently extracted from the grape residue, and had a positive effect on the stability of anthocyanins.

Degradation kinetics of anthocyanin and physicochemical changes in fermented turnip juice exposed to pulsed UV light

In this study, the effects of pulsed UV (PUV) light on the degradation kinetics of anthocyanins and physicochemical properties of turnip juice were investigated. PUV light was applied to turnip juice at 3 different distances (5, 8, 13cm) from the quartz window of the xenon lamp for 5 different times (5, 15, 30, 45, 60s). The pH, total acidity (% lactic acid), monomeric anthocyanin content, color density, hue, brightness, and percent color components (yellow, red, and blue) of turnip juice changed significantly after PUV-light treatments at each level. The maximum degradation of anthocyanin after PUV-light treatments was found to be about 63%. The anthocyanin degradation, brightness, yellow and blue color (%) increased, while red color (%) decreased with longer treatment time and shorter distance. The degradation of monomeric anthocyanins in turnip juice exposed to PUV light was described by the Weibull model (R2 0.982-0.998, RMSE 0.087-0.133) more accurately than the first-order kinetics (R2 0.906-0.992, RMSE 0.071-0.192).

Oak barrel tannin and toasting temperature: Effects on red wine anthocyanin chemistry

Oak-derived compounds are generally considered to be important in red wine perception and color qualities. In this study, the percentage of loss and kinetic rates of degradation of monomeric anthocyanins as well as the formation of pigmented tannins were monitored in red wines aged for 8 and 12 months in oak barrels differentiated by stave ellagitannin content (low LTP, medium MTP and high HTP) and toasting level (160 and 180 °C as initial temperature). The malvidin coumaroyl glucoside is found to be the most reactive monomeric anthocyanin during barrel aging. While color intensity was not affected, the results indicated that in presence of high ellagitannin content red wines exhibit a lower loss and slower degradation of monomeric anthocyanins and slower formation of pigmented tannins.

Physicochemical characterization of pomegranate wines fermented with three different Saccharomyces cerevisiae yeast strains

Three commercial Saccharomyces cerevisiae yeast strains: Viniferm Revelación, Viniferm SV and Viniferm PDM were evaluated for the production of pomegranate wine from a juice coupage of the two well-known varieties Mollar and Wonderfull. Further malolactic fermentation was carried out spontaneously. The same fermentation patterns were observed for pH, titratable acidity, density, sugar consumption, and ethanol and glycerol production. Glucose was exhausted while fructose residues remained at the end of alcoholic fermentation. A high ethanol concentration (10.91±0.27% v/v) in combination with 1.49g/L glycerol was achieved. Citric acid concentration increased rapidly a 31.7%, malic acid disappeared as result of malolactic fermentation and the lactic acid levels reached values between 0.40 and 0.96g/L. The analysis of CIEa parameter and total anthocyanin content highlights a lower degradation of monomeric anthocyanins during winemaking with Viniferm PDM yeast. The resulting wine retains a 34.5% of total anthocyanin content of pomegranate juice blend.

Effect of Storage on Anthocyanin Degradation in Black Mulberry Juice and Concentrates

Anthocyanins present in fruits and vegetables are receiving increased attention because of their potential antioxidant activity but are very susceptible to degradation during processing and storage. Effect of storage on kinetics of anthocyanin degradation and hydroxymethylfurfural (HMF) formation in black mulberry juice and concentrate was determined during 8 months of storage at temperatures of 5°, 20°, 30°, and 40 °C. The monomeric anthocyanin degradation was in accordance with the first-order reaction kinetics and the activation energies of anthocyanin degradation in black mulberry juice and concentrate were found as 56.48 and 49.75 kJ mol−1, respectively. HMF formation in black mulberry juice and concentrate increased linearly with storage time and temperature and followed zero-order reactions. The activation energies of HMF formation in black mulberry juice and concentrate were found as 75.70 and 104.11 kJ mol−1, respectively. The losses of antioxidant activity for black mulberry juice and concentrate during storage at different temperatures were in the ranges of 4.87–16.01 and 4.47–33.57 %, respectively. Antioxidant activity in black mulberry juice and concentrate was correlated with total monomeric anthocyanins.

Studies on the preparative isolation and stability of seven main anthocyanins from Yan 73 grape

[corrected] Seven anthocyanin monomers of Yan 73 grape were separated using preparative HPLC and identified by UPLC-ESI-MS/MS. The stabilities of the seven isolated anthocyanins to light, temperature and pH were also investigated. Seven anthocyanin monomers were successfully isolated with an Xbridge Prep C18 column on a preparative scale. The pigments delphinidin-3-O-glucoside, malvidin-3-O-acetylglucoside and malvidin-3-O-coumarylglucoside were yielded in a one-step separation by preparative HPLC, with purities up to 99.9%, 91.7% and 95.5%, respectively. The pigments cyanidin-3-O-glucoside, petunidin-3-O-glucoside, peonidin-3-O-glucoside, and malvidin-3-O-glucoside were further purified with another elution method and their purities were all improved up to 99.9%. Monomeric anthocyanin degradation fitted a first-order reaction model. The seven isolated anthocyanins were significantly more stable in the dark than under light. High temperature was also unfavourable for the stability of anthocyanins. The anthocyanins were more stable at lower pH than at higher pH. In addition, among these anthocyanins, delphinidin-3-O-glucoside, malvidin-3-O-acetylglucoside and malvidin-3-O-coumarylglucoside were more susceptible to light, heat, and pH than the others. A simple and clean isolation method of seven anthocyanin monomers from Yan 73 grape was established. The stabilities of the seven anthocyanin monomers to light, temperature and pH were different, but the trends in changes were similar.

A comparative study on different concentration methods of extracts obtained from two raspberries (Rubus idaeus L.) cultivars: evaluation of anthocyanins and phenolics contents and antioxidant activity

SummaryThe effects of conventional (CV) and microwave (MW) heating on total soluble solid (TSS) content, total anthocyanin content (TAC), total phenolic content (TPC) and antioxidant activity of raspberry juice obtained from two cultivars of Amol (AM) and Siyahkal (SK) were scrutinised. Antioxidant activity of the juices was measured by 2,2 diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging capacity and expressed as EC50 value. In the both methods, the concentration rate constant for the juices was significantly decreased by increasing operational pressure from 12 to 100 kPa (P < 0.05). A first‐order reaction kinetic model was successfully fitted for the degradation of monomeric anthocyanins at all operating pressures. The results also showed that thermal treatment of MW compared CV in both SK and AM cultivars caused a lower decrease in the TAC, TPC and antioxidant activity. Moreover, the changes in trend of the antioxidant activities due to the thermal treatment were positively correlated with the TPC (r = 0.74, P < 0.05) and TAC (r = 0.61, P < 0.05).

Thermal degradation kinetics of anthocyanins and visual colour of Urmu mulberry (Morus nigra L.)

Urmu mulberry (Morus nigra L.) juice was concentrated from 15.02 to 45.20 °Brix by rotary vacuum evaporator at 40°C. The objectives of this study were to determine the titratable acidity, soluble solid content, antioxidant capacity, total monomeric anthocyanins and total phenolic matter in prepared concentrate, to investigate the thermal degradation kinetics of anthocyanins and Hunter colour parameters (L∗, a∗, b∗) and total colour difference (TCD∗) and to develop a relationship between visual colour and anthocyanin during thermal processing at 60, 70 and 80°C. Monomeric anthocyanin degradation showed a first order reaction kinetics. The zero order, first order and a combined kinetics model were applied to the changes in Hunter colour parameters (L∗, a∗ and b∗) and total colour difference (TCD∗). All colour parameters followed an apparent combined kinetics model. The degradation of anthocyanins showed positive correlation with a∗, b∗ and L∗ and negative correlation with TCD∗.

Effect of grape variety on the evolution of sugars, hydroxymethylfurfural, polyphenols and antioxidant activity during grape must cooking

SummaryGrape must cooking is a traditional practice used for the production of foodstuff worldwide such as traditional balsamic vinegar. The aim of this work was to reveal the effect of grape variety on the evolution of the main chemical components in grape must during cooking. To this end, two grape must varieties (red Lambrusco and white Trebbiano grapes) were cooked and analysed. The monosaccharide concentration decreased because cooking resulting in the formation of 5‐hydroxymethylfurfural. At the end of cooking, the antioxidant activity and polyphenol concentration were higher and the 5‐hydroxymethylfurfural was lower in Lambrusco than in Trebbiano must. Additional changes involved degradation of monomeric anthocyanins resulting in the formation of the corresponding phenolic acids. From a health point of view, the high antioxidant activity and polyphenol concentration and the low 5‐hydroxymethylfurfural concentration make cooked red Lambrusco must a safer raw starting material for making traditional balsamic vinegar.

Kinetics of Anthocyanin Degradation and Browning in Reconstituted Blackberry Juice Treated at High Temperatures (100−180 °C)

Monomeric anthocyanin degradation and nonenzymatic browning (NEB) index have been determined in reconstituted blackberry juice heated at high temperature in a hermetically sealed cell. Statistical analysis demonstrated that, when the temperature range (100-180 degrees C) was divided into two subranges (100-140 and 140-180 degrees C) for anthocyanin degradation, reaction kinetics were well represented by two sequential first-order reactions. The activation energy for NEB from 100 to 180 degrees C (106 kJxmol(-1)) was slightly higher than the anthocyanin value at the lower temperature range (92 kJxmol(-1)), but was more than twice the value for the higher range (44 kJxmol(-1)). The reaction rate constant at 140 degrees C for anthocyanin degradation (3.5 x 10(-3) s(-1)) was two times that for the NEB index (1.6 x 10(-3) s(-1)). Hence, anthocyanin degradation was faster than the appearance of NEB products. The non-isothermal method developed allows estimating kinetic parameters and thereby generating temperature profiles of heat processes that would help preserve the nutritional properties of foods during high-temperature processes.

Experimental in vitro arterial reactivity and tissue culture solutions alter the time-dependent stability of anthocyanins from elderberry, chokeberry, and bilberry extracts

We examined the effect of solutions commonly used for in vitro assessment of blood vessel physiology and pharmacology on the half-lives of monomeric anthocyanins contained in extracts from elderberry, chokeberry, and bilberry. We observed that monomeric anthocyanin degradation in all extracts was accelerated when they were solubilized in an in vitro vascular physiological salt solution (PSS) compared with extracts in purified water. Degradation was accelerated further by increasing the temperature of the PSS to 37°C and bubbling it with 95% oxygen/5% carbon dioxide. A common, complex, tissue culture media yielded similar results to the physiological salt solution at 37°C. We also observed that the percentage polymeric color estimated by bisulfite bleaching corresponded to monomeric degradation in PSS. These results suggest that exposure of anthocyanins to physiological conditions that mimic those in the human body may stimulate the conversion of monomeric anthocyanins to their polymeric forms. Such conversion would probably contribute to the effects of anthocyanins on physiological functions in in vitro experiments and needs to be considered when evaluating effects of these compounds on physiological processes.

Production of γ-aminobutyric acid in black raspberry juice during fermentation by Lactobacillus brevis GABA100

Black raspberry juice was fermented to produce γ-aminobutyric acid (GABA) using lactic acid bacteria ( Lactobacillus brevis GABA 100) at different temperatures (25, 30, or 37 °C) and pHs (3.5, 4, 4.5, 5, 5.5, or 6) for 15 days. Concentrations of GABA in the juices were determined during fermentation using HPLC. GABA was produced continuously even if the viable bacterial counts markedly decreased. The fermentation at 30 °C generally showed higher production of GABA in the juices than those at 25 and 37 °C. The GABA in the juices fermented at 30 °C reached the maximum levels on the 12th day. The juices fermented at lower pH and lower temperature showed a lower degradation of monomeric anthocyanins. The results suggest that black raspberry juice can be GABA enriched using lactic acid bacteria.

Experimental in vitro arterial reactivity and tissue culture solutions alter the time dependent stability of anthocyanins from chokeberry, bilberry and elderberry extracts.

Acute exposure to anthocyanin enriched extracts from chokeberry (Ch), bilberry (B) and elderberry (E) produces endothelium‐dependent, NO mediated vasorelaxation of porcine coronary arteries. Extracts at 0.05mgTa/L also attenuate impaired vasorelaxation resulting from external or internal oxidant stress. Determining the stability of these extracts in in vitro settings is necessary to evaluate their long term effects on arteries. Therefore, we examined the stability of monomeric anthocyanins from Ch, B and E in common in vitro arterial function solutions. Reference extract solutions (0.75mg/ml in DD H2O at 21C)showed less than 25% monomeric anthocyanin degradation over a period of 9 days as determined by the pH differential method. Solutions made with a physiological salt solution (PSS) used for in vitro arterial reactivity studies showed significantly greater degradation at 21C.(1/2 life, hrs: Ch= 13, E=35, B=4.6). Degradation in PSS was increased 3–4 fold at 37C and 2 fold more with 95%O2/5%CO2 added. Similar results were seen in Dulbecco's modified Eagle's media solutions at 37C. Analysis of degradation by the bisulfite method revealed time dependent anthocyanin polymerization in in vitro arterial solutions. Thus solutions used to study arterial function in vitro produce significant degradation and polymerization of monomeric anthocyanins from Ch, B and E. These factors must be taken into account in the design and interpretation of studies that examine long term effects of anthocyanins on arterial function in vitro. (Supported by IUSM REGrant #39407‐1090 and the Lutheran Foundation of Indiana Grant # 6721712)

STORAGE STABILITY OF STRAWBERRY JAM COLOR ENHANCED WITH BLACK CARROT JUICE CONCENTRATE

Black carrot juice concentrate was added to enhance the color of strawberry jams prepared from two locally grown cultivars, Osmanli and Kara. Compared to other cultivars processed to jams, these two cultivars are lightly colored but very aromatic. Color and pigment stability of colored and noncolored (control) strawberry jams were studied during storage. The use of black carrot concentrate as a source of natural colorant stabilized the color of strawberry jam. The stabilization was more noticeable for jams prepared from Osmanli cultivar. Monomeric anthocyanin degradation was fitted to a first-order reaction model. Storage temperature had a strong influence on anthocyanin degradation. As the storage temperature increased, the stability of anthocyanins decreased significantly in both colored and noncolored jams. Parallel to decrease in monomeric anthocyanins, hue (h°) values of all jam samples increased throughout the storage. However, increase in h° values was much smaller in colored samples than in noncolored samples. High correlation was found between h° value and anthocyanin concentration at 22C (r = 0.910-0.978) and 37C (r = 0.931-0.981).

Effects of temperature, solid content and pH on the stability of black carrot anthocyanins

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 ( E a) were obtained during heating than during storage with increasing solid contents. At 30–64° Brix, E a 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. Q 10 values at 20–37 °C were as high as 3.1 at 45° Brix and 3.6 at 64° Brix.

Characterization of Anthocyanin-Rich Waste from Purple Corncobs (Zea maysL.) and Its Application to Color Milk

Pigment production from anthocyanin-rich purple corncobs generates a deeply colored waste precipitate. Our objectives were to characterize this anthocyanin-rich waste (ARW) and to find a suitable application in a food matrix. Composition and solubility characteristics of ARW were evaluated. Color (CIELAB) and pigment (monomeric anthocyanin and HPLC profiles) stability of ARW in milk (35 mg/100 mL) were evaluated using an accelerated test at 70 degrees C and phosphate buffer as a control. ARW provided milk an attractive purple hue (324-347 degrees ). Monomeric anthocyanin degradation followed zero-order kinetics in skim and whole milk and second-order kinetics in the control, with half-lives of 173, 223, and 44 min at 70 degrees C, respectively. ARW shows potential as a natural colorant for a pH range unusual for anthocyanin applications. A protective effect of matrix constituents on the stability of anthocyanins was evident. Anthocyanins may interact with different compounds in biological systems when the pH values are close to neutral.

Glycoalkaloid Content and Anthocyanin Stability to Alkaline Treatment of Red‐Fleshed Potato Extracts

ABSTRACTRed‐fleshed potato (Solanum tuberosum) breeding clones were screened for steroidal glycoalkaloid (SGA) content. SGAs and anthocyanins (ACN) were characterized by HPLC and Mass Spectroscopy (MS). Total SGA ranged from 2.0 to 36.3 mg/100g tuber. Two cultivars with highest anthocyanin content, showed low levels of SGAs. The effect of alkaline treatments on SGA precipitation, anthocyanin content and profile was studied by adjusting the pH of aqueous extracts from 7.6 to 11. Complete removal of SGAs from colored extracts was achieved at pH > 9.2, however it caused substantial anthocyanin loss. Best results were obtained at pH 8.0 with 30% monomeric anthocyanin degradation and 90% SGA precipitation.

Radish Anthocyanin Extract as a Natural Red Colorant for Maraschino Cherries

ABSTRACTRed radish anthocyanin extract (RAE) was investigated to color brined cherries as an alternative to FD&C Red No. 40. Primary and secondary bleached cherries were colored using two concentrations of RAE (600 and 1200 mg/L syrup, C1 and C2) and FD&C Red No. 40 (200 ppm). Color and pigment stability of secondary bleached cherries and syrup colored with RAE were evaluated during storage (25°C). CIELAB, chroma and hue angle, showed that RAE imparted color extremely close to that of FD&C Red No. 40, for > 6 mo storage. Monomeric anthocyanin degradation followed first‐order kinetics, with half‐lives of 29 and 33 wk for syrups colored with RAE C1 and RAE C2, respectively. Higher anthocyanin concentration exerted a protective effect on color stability. Exposure to light slightly accelerated L*, a*, and monomeric anthocyanin degradation.