Thermal Stability Of Anthocyanins Research Articles

Effect of five polyphenols on the stability of purple cabbage anthocyanins in simulated beverage systems containing L-ascorbic acid

Purple cabbage shows great potential as a natural colorant source for commercial beverages due to its high anthocyanin content and wide availability. However, the application of purple cabbage anthocyanins in the food industry is limited by its unstable characteristics. This study aimed to investigate the effect of 0.4% concentration of catechin, epigallocatechin gallate, vanillin, gallic acid (GA), and rosmarinic acid on the stability of purple cabbage anthocyanins in beverage systems. The results showed that all five polyphenols increased the color intensity of anthocyanins and the copigmentation effect increased with the increased polyphenol. Five polyphenols were observed to enhance the color and thermal stability of anthocyanins in beverage systems, while GA performed best. The addition of GA to the beverage systems achieved a greater improvement in color stability regarding absorbance value (increased by 247.70%) and total color change (decreased by 70.34%). In addition, degradation kinetic reaction showed the lowest k (0.0466 1/d) and highest t1/2 (14.87 d) for anthocyanin degradation with GA addition. This study provides a potential solution to enhance anthocyanin stability and extend beverage shelf life through GA addition.

Interactions between zein and anthocyanins at different pH: Structural characterization, binding mechanism and stability

Zein-anthocyanin nanoparticles (ZACNPs) at different pH values were successfully developed to stabilize anthocyanins based on the self-assembly properties of zein. The structural characterization by the Fourier infrared spectroscopy, fluorescence spectroscopy, differential scanning calorimetry and molecular docking analysis showed that the interactions between anthocyanins and zein were driven by the hydrogen bonds formed between the hydroxyl and carbonyl oxygen groups on anthocyanin glycoside groups and the amino acid residues (glutamine and serine), as well as the hydrophobic interactions from the A or B ring of anthocyanins and the amino acid residues of zein. The binding energy of zein to two anthocyanin monomers cyanidin 3-O-glucoside and delphinidin 3-O-glucoside was 8.2 and 7.4 kcal/mol. Further property examinations of ZACNPs showed that the thermal stability of anthocyanins at a ratio of zein:ACN = 1:0.3 was improved by 56.64 % (90 °C, 2 h), and the storage stability increased by up to 31.11 % at pH 2. In addition, the antioxidant activity of ZACNPs (zein:ACN = 1:0.3) was significantly enhanced, and the DPPH, ABTS radical scavenging activities, FRAP and ORAC value reached 87.73 %, 87.89 %, 435.5 μg/mL, 90.58 μmol/mL at pH 4, respectively. These results suggested that combining zein to anthocyanins is a feasible method to stabilize anthocyanins.

안토시아닌 조성이 다른 베리류 3종의 열안정성 비교

Anthocyanins are natural pigments responsible for the red, purple, and blue colors in berries. The stability of anthocyanins can be affected by various factors, such as pH, temperature, and other components. This study investigated the degradation kinetics of anthocyanins in representative berries. Among the most consumed berries in the Korean population, black chokeberry, black mulberry, and blueberry were chosen due to their high anthocyanin contents. The berries contained anthocyanins with different aglycones and sugar moieties as follows: cyanidin-3-galactoside (63%) and cyanidin-3-arabinoside (30%) in black chokeberries, cyanidin-3-glucoside (70%) and cyanidin-3-rutinoside (25%) in black mulberries, and malvidin-3-galactoside (35%), malvidin-3-arabinoside (16%), and delphinidin-3-galactoside (14%) in blueberries. After heating at 100℃ for 60 min, the degradation of anthocyanins was highest in the black chokeberries (62%), followed by blueberries (54%) and black mulberries (50%). Within the same aglycone, glycosylated anthocyanins with glucose had higher retention compared to those with galactose or arabinose. Lightness (LSUP*/SUP) showed a tendency to increase with increasing heating time. Color difference (ΔESUP*/SUP) was lowest in the black mulberries and highest in the blueberries. These results indicate that the thermal stability of anthocyanins was in the following order: black mulberry blueberry black chokeberry.

Interaction of mulberry anthocyanins with soybean protein isolate: effect on the stability of anthocyanins and protein in vitro digestion characteristics

SummaryThe interactions of anthocyanins and proteins might mutually influence each other on the physicochemical and functional properties. In this study, the interaction mechanism of soybean protein isolate (SPI) with mulberry anthocyanins (MA), and its effect on the thermal stability of anthocyanins and protein subunits’ digestibility were investigated through multiple spectroscopies and in vitro gastrointestinal models. Results showed that cyanidin‐3‐O‐glucoside (C3G), the main anthocyanin monomer in MA, could bind to SPI through hydrophobic interactions, resulting in static fluorescence quenching of SPI. The secondary structure of SPI changed by binding to C3G, with an increase of β‐sheet and a decrease of α‐helix and random coil. The formation of the SPI‐MA complexes improved the thermal stability of MA at 353 K, while, no significant protection occurred during heating at 368 K. Complexation with MA promoted the digestibility of SPI by pepsin, especially the α′ and α subunits of β‐conglycinin and the basic subunit of glycinin, and slightly delayed the digestibility of SPI under intestinal fluid. These results provide an in‐depth understanding of the influence of the protein‐anthocyanin interactions on the stability of anthocyanins and protein digestibility.

Copigmentation and stabilization of anthocyanins using organic molecules and encapsulation techniques

Natural colorants/pigments such as anthocyanins, carotenoids, betalains, and chlorophylls have been generally used in the food industry as coloring agents. However, there are challenges related to color fading during food processing, storage, and commercialization due to the low stability of natural colorants compared to synthetic ones. Among them, anthocyanins are potential food colorants due to their color, low toxicity, and biological properties. However, the low chemical and thermal stability of anthocyanins have limited their use on a commercial scale. Copigmentation is the most commonly used technique for anthocyanin stabilization. This technique provides many advantages associated with the stability of anthocyanins. Natural anthocyanin pigments and copigments (e.g. polymers, phenolic compounds, and carbohydrates) form non-covalent complexes, which stabilize and modulate colors in a wide range of plants, fruits, and food products derived from them (including wines, jams, purees, and syrups). Over the past decade, research studies have been conducted to understand the molecular structure of copigment and the mechanism of copigmentation. This review summarizes this phenomenon to provide a comprehensive description of the interactions between anthocyanin and copigment (the dispersion and electrostatic components of π − π stacking, the hydrophobic effect, and hydrogen-bonding) occurring in copigmentation complexes. The trend of integrating copigmentation and encapsulation has been recently started to develop. In this paper, we also attempt to provide a comprehensive view of the effective approaches including spray and freeze-drying, emulsification, gelation, and their combinations for encapsulating copigmented anthocyanins.

Effects of Low Acyl and High Acyl Gellan Gum on the Thermal Stability of Anthocyanins from Passion Fruit Peel in Model Beverages

Effects of Low Acyl and High Acyl Gellan Gum on the Thermal Stability of Anthocyanins from Passion Fruit Peel in Model Beverages

Effects of β-cyclodextrin, whey protein, and soy protein on the thermal and storage stability of anthocyanins obtained from purple-fleshed sweet potatoes

The effects of β-cyclodextrin (β-CD), whey protein (WP), and soy protein (SP) on the color loss and degradation of anthocyanins in purple-fleshed sweet potato anthocyanin extracts (PFSPAEs) during thermal treatment and shelf-life storage in model beverage systems by performing chromaticity, degradation kinetics, and principal component analysis. Results showed that WP and SP improved the thermal stability of the PFSPAE, but WP accelerated the color loss of the extract. However, the addition of 25 mg/L SP improved the color and thermal stability of the anthocyanins when heated at 100 °C for 30 min. With regard to the shelf-life storage, the addition of SP and WP showed non-significant effect on the storage stability of the PFSPAE. However, the addition of 2500 mg/L β-CD significantly improved the storage stability of the PFSPAE. In summary, our findings provide useful information on improving the thermal and storage stability of PFSPAEs in beverage systems using food biopolymers.

Blackberry pomace microspheres: An approach on anthocyanin degradation

ABSTRACT Blackberry pomace is a rich source of antioxidant compounds, including anthocyanins, but these compounds degrade easily in the presence of high temperatures. Therefore, the present study aimed to evaluate the effect of temperature on anthocyanin degradation in spray-dried blackberry pomace extract. Maltodextrin was used as a drying aid agent in a spray drying process to produce microspheres. The experiment was set up at Maringá-PR, Brazil (23º 25’ 31” S, 51º 56’ 19” W, 596 m altitude). The thermal stability of anthocyanins was evaluated in the presence and absence of copigments at different temperatures ranging from 70 °C to 100 °C using degradation kinetics. The role of maltodextrin in protecting anthocyanins during the spray drying process was studied at high temperatures. The highest anthocyanin stability was found at 70 °C. We also studied the effect of copigment phytic acid on the stability of anthocyanin and found that the copigment plays an important role in anthocyanin protection at high temperatures. The spray drying process with maltodextrin is a feasible technique for the preservation of food products and can improve anthocyanin’s thermal stability. The reuse of industrial wastes, such as blackberry pomace along with preservation techniques, can be a good strategy to reduce their negative impact on the environment.

Stabilization of black rice anthocyanins by self-assembled silk fibroin nanofibrils: Morphology, spectroscopy and thermal protection

Nanofibrillated proteins possess diverse techno-functional properties are considered as matrices for stabilizing bioactive agents. In this study, the morphology and interaction of silk fibroin nanofibrils (SNFs) with black rice anthocyanins (ACN) were investigated through multiple microscopy and spectroscopic techniques. The impact of SNFs on the thermal stability of ACN was analyzed. Nanofibrils with diameter less than 20 nm were self-assembled from silk fibroin (SF) lyophilized powder solution at pH 6.0. A static model occurred in the interactions of cyanidin-3-O-glucoside (C3G, the major anthocyanin in black rice) with SF and SNFs. C3G binding altered the secondary structures of SF and SNFs. Moreover, the thermal retention rates of ACN combined with SF and SNFs were significantly (P < 0.05) higher than that of ACN alone followed the order of SNFs-ACN (60.87%) > SF-ACN (57.47%) > ACN alone (40.33%) after heating 120 min at 80 °C and SNFs-ACN (50.42%) > SF-ACN (32.81%) > ACN alone (23.64%) after heating 120 min at 90 °C. The half-life (t1/2) of thermal degradation of ACN was elongated in SNFs-ACN complex compared with that in SF-ACN complex. These results showed that SNFs effectively binding with C3G and exhibit better protective effects on the thermal stability of ACN than SF.

Improvement of stability of blueberry anthocyanins by carboxymethyl starch/xanthan gum combinations microencapsulation

The study was to improve the stability of blueberry anthocyanins (ANS) by encapsulating it with carboxymethyl starch (CMS)/xanthan gum (XG) combinations of five ratios (CMS/XG: 30/1, 60/1, 90/1, 120/1, 150/1, w/w). The results revealed that all the microcapsules presented high encapsulation efficiency. Fluorescence microscopy showed that ANS distributed homogenously through CMS/XG combinations, and the microcapsules revealed red-purple color. Thermogravimetric analysis (TGA) demonstrated that CMS/XG combinations working as wall materials increased the thermal stability of ANS. The cross-linking interactions between the CMS/XG combinations and ANS were confirmed by FTIR and 13C solid-state NMR. Microcapsules created with an CMS/XG ratio of 30/1 provided superior antioxidant stability. Furthermore, the storage stability results showed that the stability of ANS was increased to 76.11% after the 30-day storage (37 °C) through CMS/XG. The in vitro release experiments revealed that the ANS were majorly retained inside CMS/XG-ANS microcapsules in the stomach, and released in the intestine. CMS/XG combinations microencapsulation can be a suitable method for stabilizing blueberry anthocyanins.

Thermal stability of anthocyanins and colourless phenolics in pomegranate (Punica granatum L.) juices and model solutions

The present study aimed at a systematic assessment of the factors influencing the anthocyanin (AC) stability and colour retention of pomegranate juices and less complex model solutions with particular focus on the effects of colourless phenolic copigments (CP). The thermal stability of ACs in three pomegranate juices obtained from isolated arils and the entire fruit with and without previous steaming, in model solutions with AC:CP ratios ranging from 1:0 to 1:4 (m/m), and in two purified extracts from pomegranate juices characterised by different phenolic profiles, respectively, was investigated upon heating at 60, 70, 80 and 90°C for 15min to 5h. The thermal impact on the AC and CP contents, and the formation of 5-hydroxymethylfurfural (HMF) and AC degradation products were monitored using HPLC-DAD–MSn. Total phenolic contents, antioxidant capacity and colour properties were determined spectrophotometrically.Heating at 90°C for 5h resulted in total AC losses ranging from 76% to 87% of the initial AC levels in the juices, 78% in both extracts as well as 57% and ∼78% in the model solutions, showing the best stability at an AC:CP ratio of 1:2 and in juices having the highest initial AC contents, respectively. In contrast, the AC stability was independent of total phenolic contents, and low and high molecular pomegranate matrix components (such as organic acids and sugars). Good correlation of the AC contents with red colour (a∗) was observed for all samples at elevated temperatures (70–90°C). The stability of putative health-promoting polyphenols of pomegranate juices was not markedly affected by the thermal treatment. Unexpectedly, the HMF contents only slightly increased upon forced heating. Therefore, the visual appearance does not adequately reflect the quality and storage stability of pomegranate juices.

Influence of Cooking on Anthocyanins in Black Rice (Oryza sativa L. japonica var. SBR)

The composition and thermal stability of anthocyanins in black rice (Oryza sativa L. japonica var. SBR) produced in California were investigated. Six anthocyanin pigments were identified and quantified by high performance liquid chromatography using photo diode-array detection (HPLC-PDA) and electrospray ionization mass spectrometry [LC-(ESI)MS/MS]. The predominant anthocyanins are cyanidin-3-glucoside (572.47 microg/g; 91.13% of total) and peonidin-3-glucoside (29.78 microg/g; 4.74% of total). Minor constituents included three cyanidin-dihexoside isomers and one cyanidin hexoside. Thermal stability of anthocyanins was assessed in rice cooked using a rice cooker, pressure cooker, or on a gas range. All cooking methods caused significant (P < 0.001) decreases in the anthocyanins identified. Pressure cooking resulted in the greatest loss of cyanidin-3-glucoside (79.8%) followed by the rice cooker (74.2%) and gas range (65.4%). Conversely, levels of protocatechuic acid increased 2.7 to 3.4 times in response to all cooking methods. These findings indicate that cooking black rice results in the thermal degradation of cyanidin-3-glucoside and concomitant production of protocatechuic acid.

Composition and Thermal Stability of Anthocyanins from Chinese Purple Corn (Zea mays L.)

Chinese purple corn extracts ( Zea mays L., Zhuozhou, Hebei, China) (EZPC) were selected among five Chinese purple corn hybrids due to their higher anthocyanin content, and their thermal stability was evaluated. The total anthocyanin content and total phenolic content of EZPC were 304.5 +/- 16.32 mg of cyanidin-3-glucoside equiv/100 g of dry seeds and 489.8 +/- 24.90 mg of gallic acid equiv/100 g of dry seeds, respectively. Moreover, the individual anthocyanins of EZPC were determined by HPLC-DAD/ESI-MS analysis. Seven main compounds were determined, including cyanidin-3-(malonylglucoside), cyanidin-3-O-glucoside-2-malonylglucoside, cyanidin-3-O-glucoside, peonidin-3-O-glucoside, peonidin-3-(malonylglucoside), pelargonidin-3-(6''-malonylglucoside), and peonidin-3-(dimalonylglucoside). The thermal stability of EZPC was studied by differential scanning calorimetry. Thermodynamic analysis showed that the conversion of EZPC followed an Arrhenius relationship, where the delta enthalpy (H) and activation energy (E(a)) were 97.0 J/g and 204 +/- 2.72 kJ/mol, respectively. Furthermore, the relationships between the degree of conversion of EZPC and time or temperature were reported. This study demonstrated that the evaluated Chinese purple corn hybrids are a natural source of anthocyanins and are stable over a wide range of temperatures and times.

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.

THERMAL STABILITY OF BLACK CARROT ANTHOCYANINS IN BLOND ORANGE JUICE

Abstract Blond orange juice was colored with black carrot concentrate as an alternative to blood orange juice. Thermal stability of anthocyanins from black carrots in orange juice was determined at 70, 80 and 90C. Anthocyanin degradation in colored blond orange juice followed to first‐order reaction kinetics. As expected, the degradation rate was dependent on temperature, being faster at higher temperatures. Half‐lives for anthocyanin degradation were 12.5, 6.3 and 3.1 h at 70, 80 and 90C, respectively. Between 70–90C, activation energy was 72.03 kJ mol‐1. Results showed that coloring blond orange juice with black carrot concentrate resulted in a much more stable product as compared with blood orange juice.