Effects of sucrose and copigment sources on the major anthocyanins isolated from sour cherries

Synergistic effects of intermolecular copigmentation and high-pressure processing on stabilizing mangosteen pericarp anthocyanins

The mangosteen pericarp contains unstable non-acylated ACNs, rendering it prone to degradation. Therefore, intermolecular copigmentation of semi-purified ACNs (SPA) with tartaric acid (SPA-TA), sinapic acid (SPA-SA), catechin (SPA-CE), and sucrose (SPA-SU) in 1:5 and 1:10 M ratios were used to increase their stability during storage for 77 days at 25 ± 1 °C in pH 3 buffer solution. The SPA-TA1:5 complex showed the significant highest stability of total monomeric ACN content (TMAC) with a half-life (t1/2) = 56.9 days, cyanidin-3-O-sophoroside (C3S) with t1/2 = 48.1 days and color retention (69.80 %) compare to SPA with TMAC (t1/2 = 37.4), C3S (t1/2 = 13.3) and color retention (57.2 %) after 49 days (p < 0.05). The thermal stability of SPA-TA1:5 at 60 °C improved after high-pressure processing (HPP) at 300 and 500 MPa for 10 min. Fourier-transform infrared spectroscopy (FT-IR) and molecular docking indicate copigmentation interactions, including hydrogen bonding and π-π interactions. This study demonstrates a sustainable method to stabilize non-acylated ACNs, offering a natural alternative to synthetic dyes for food and beverage applications.

Copigmentation effect on red cabbage anthocyanins, investigation of their cellular viability and interaction mechanism

Anthocyanins (ANS) are an appealing substitute to synthetic colorants; but their practical applicability is limited due to low color stability. Copigmentation can improve both complex's color stability as well as intensity. In this study, we examined the interaction of red cabbage ANS with copigments i.e., two organic acid, two phenolic acid, a flavonoid and three amino acid through experimental and theoretical approach. Among various copigments, phenolic and organic acids induced a strong bathochromic shift of 6.5-7.1 nm and 5.1-11.6 nm. Thermal analysis, anthocyanin content and chromaticity, were used to assess the color intensity and stability of ANS, at 4 ℃, 25 ± 2 ℃, sunlight, oxygen, and heat. Results revealed that oxalic acid copigmented complex followed by chlorogenic and rosmarinic acid exhibits significant thermal stability with greater retention rate at 120 ℃ and 150 ℃. In case of anthocyanin content and colorimetric parameters, chlorogenic acid followed by oxalic and rosmarinic acid exhibits significantly improved stability. Rosmarinic acid copigmented sample showed good cell viability at high concentration (200 µg/mL). Steered molecular dynamics and thermodynamic analysis reveals chlorogenic and rosmarinic acid as promising copigments involving conventional H-bonds, π-π interactions, and carbon hydrogen bonds.

Progress on molecular modification and functional applications of anthocyanins

Anthocyanins have attracted a lot of attention in the fields of natural pigments, food packaging, and functional foods due to their color, antioxidant, and nutraceutical properties. However, the poor chemical stability and low bioavailability of anthocyanins currently limit their application in the food industry. Various methods can be used to modify the structure of anthocyanins and thus improve their stability and bioavailability characteristics under food processing, storage, and gastrointestinal conditions. This paper aims to review in vitro modification methods for altering the molecular structure of anthocyanins, as well as their resulting improved properties such as color, stability, solubility, and antioxidant properties, and functional applications as pigments, sensors and functional foods. In industrial production, by mixing co-pigments with anthocyanins in food systems, the color and stability of anthocyanins can be improved by using non-covalent co-pigmentation. By acylation of fatty acids and aromatic acids with anthocyanins before incorporation into food systems, the surface activity of anthocyanins can be activated and their antioxidant and bioactivity can be improved. Various other chemical modification methods, such as methylation, glycosylation, and the formation of pyranoanthocyanins, can also be utilized to tailor the molecular properties of anthocyanins expanding their range of applications in the food industry.

Dye stability of black cherry plum anthocyanins in the interaction with co-pigments and sucrose sweetener

In this research, the co-pigmentation reactions between black cherry plum (Prunus cerasifera Ehrh. cv. Pissardii Nigra) anthocyanins and caffeic, gallic, 4-hydroxybenzoic, malic, and tannic acids with different concentrations (0, 120, 240, 480, and 960 mg L-1) at various temperatures (20, 40, 60, 80, and 100°C) were investigated at pH 3.5. The strongest immediate co-pigmentations resulted at 960 mg L-1, being significantly highest using tannic acid at all temperatures. In addition, the anthocyanin stability and the brown polymeric color formation were investigated in the presence of different concentrations of sucrose sweetener (0, 30, and 60%) and different pHs (2 and 3) in the range of 0-60 h. Also, the amount of furfural was measured in the presence of 0% and 30% sucrose concentrations at pH 2 after 20 h at 90°C by HPLC (high-performance liquid chromatography), and the most polymeric color formation was observed in the concentration of 60% sucrose at pH 2 after 60 h.

Effects of sucrose degradation product furfural on cyanidin-3-O-glucoside: Mechanism of action, stability, and identification of products in sugar solutions

Anthocyanins are often affected by the sweetener sucrose during processing, which is closely related to its typical degradation product, furfural (Ff). However, the specific mechanism is unclear. In this study, Ff and cyanidin-3-O-glucoside (C3G) were used to explain the mechanism of the effect. The results showed that Ff destabilized anthocyanins by chemically reacting with C3G to generate three new adducts. Meanwhile, the color of the C3G solution changed from bright red to dark purple, and the value of the color difference (ΔE) increased significantly by 2.69. Furthermore, the new adducts were less stable than C3G and continued to promote the degradation of C3G when they coexisted with it. The above adducts were also detected in sugar solutions supplemented with C3G, and these adducts were more likely to accumulate under light storage conditions. These results provide a theoretical basis for reducing anthocyanin loss in food processing.

The stability of phenolic compounds and the colour of lingonberry juice with the addition of different sweeteners during thermal treatment and storage

Lingonberries (Vaccinium vitis-idaea L.) are rich in phenolic compounds associated with several health benefits. The berries are also astringent, sour, and bitter and the addition of a sweetener is necessary to increase the palatability of lingonberry products. The addition of a sweetener may, however, affect the stability of phenolic compounds in the product. The aim of this study was thus to determine the effects of the addition of sweeteners (sucrose, acesulfame K or sucralose) and temperature on the stability of anthocyanins, flavonols, flavan-3-ols, hydroxycinnamic acids and the colour of lingonberry juice during thermal treatment and storage. The addition of sweeteners did not affect the stability of phenolic compounds or the colour of lingonberry juice during thermal treatment or storage. The stability of the phenolic compounds was significantly affected by temperature. Anthocyanins were the least stable of the phenolic compounds. The half-lives of total anthocyanins were 3.8, 2.0 and 0.8 h at 75, 85 and 95 °C, respectively. The half-lives during storage were 12.8 and 2.7 weeks at 6 and 22 °C, respectively. Cyanidin-3-galactoside, the major anthocyanin in lingonberries, was extensively degraded during storage, probably due to galactoside side-activities of the enzyme preparation used in juice production. After thermal treatment, the juices were darker and bluer, with lower chromaticity, while after storage, the juices were lighter, more yellow, and had higher chromaticity.

Kombucha analogs from maqui juice: Consortium age and sugar concentration effects on anthocyanin stability and its relationship with antioxidant activity and digestive enzyme inhibition

The fermentation of maqui juice (MJ), by incorporating kombucha as a starter culture, produces beverages with variable and stable anthocyanin contents. The metabolic effect of kombucha starter cultures obtained at different fermentation times was explored on the anthocyanin stability of maqui (Aristotelia chilensis (Mol.) Stuntz) juice supplemented at different concentrations of sucrose and fermented at different times. The stability of anthocyanins was associated with the levels of catechin detected in the fermentation system. This study concludes that the fermentation of MJ with sucrose (10%) and kombucha consortium of 7-days old, promotes the release and accumulation of phenolic compounds that act as co-pigments, with the best response in quality parameters of beverages such as color intensity, tone, hyperchromic effect, and a significant bathochromic shift. Finally, the additive effect of phenolic constituents with stable anthocyanins, confers to kombucha analogs an outstanding antioxidant quality and inhibitory effects on key enzymes in digestive processes.

Bioactive Natural Pigments' Extraction, Isolation, and Stability in Food Applications

Color in food has multiple effects on consumers, since this parameter is related to the quality of a product, its freshness, and even its nutrient content. Each food has a characteristic color; however, this can be affected by the technological treatments that are applied during its manufacturing process, as well as its storage. Therefore, the development of new food products should take into account consumer preferences, the physical properties of a product, food safety standards, the economy, and applications of technology. With all of this, the use of food additives, such as dyes, is increasingly important due to the interest in the natural coloring of foods, strict regulatory pressure, problems with the toxicity of synthetic food colors, and the need for globally approved colors, in addition to current food market trends that focus on the consumption of healthy, organic, and natural products. It is for this reason that there is a growing demand for natural pigments that drives the food industry to seek or improve extraction techniques, as well as to study different stability processes, considering their interactions with the food matrix, in order to meet the needs and expectations of consumers.

Biostimulants promote the accumulation of carbohydrates and biosynthesis of anthocyanins in 'Yinhongli' plum

Biostimulants play an important role in promoting crop growth and development and improving fruit yield, but their influence on fruit quality in horticulture plants is still unclear. In this study, four types of biostimulants, Ainuo (AN), Aigefu (AG), Weiguo (WG), and Guanwu Shuang (GS) were applied to the fruit surface of 'Yinhongli' plum at 60 and 75 days after anthesis to investigate their effect on carbohydrates and biosynthesis of anthocyanins, and also analyze the relationship between sugar and anthocyanin accumulation during fruit color change to ripening. Results showed that all biostimulant treatments significantly improved fruit appearance quality, and increased single fruit weight and TSS/TA. Cyanidin 3-O-glucoside and cyanidin 3-O-rutinoside, are the most important anthocyanins in the red skin of the 'Yinhongli' plum, and no anthocyanin was detected in the green skin. In addition, WG and GS treatments significantly increased the expression of structural genes involved in anthocyanin biosynthesis compared with the control, especially chalcone synthase (CHS) and flavonoid 3-O-glucosyltransferase (UFGT) at 95-105 d after anthesis, leading to anthocyanin accumulation 10 days earlier than the control. Correlation analysis showed that there was a significant correlation between total sugar and anthocyanin content during fruit coloring and ripening.

Effects of fermentation time and pH on quality of black carrot juice fermented by kefir culture during storage

BACKGROUND

The effects of fermentation time (17-48 h) and pH (3.37-4.50) on qualities of fermented beverages (FBs) produced from black carrot juice (BCJ) were monitored during storage at 4 °C for 20 weeks.

RESULTS

Fermentation and adjusting the pH level provided significant increases (up to 22%) in anthocyanin content and the absorbance value at λ_max (A_max ). Moreover, the stability of anthocyanins, color density, and A_max in FBs was somewhat higher than those in BCJ. Lactic acid showed a co-pigmentation effect on cyanidin-3-galactoside-xyloside-glucoside-sinapic acid and cyanidin-3-galactoside-xyloside-glucoside-ferulic acid. Sucrose was degraded much faster at pH 4.50 (17 h) and 4.35 (48 h) than at lower pH levels. During storage, pH 4.35 caused a balanced distribution between counts of lactic acid bacteria (LAB) and yeasts, and antioxidant activity of all FBs increased. Fermented beverages at 4.35 and 3.90 were found to be more palatable by panelists.

CONCLUSION

We recommend FB production at pH 4.35 after 48 h fermentation due to the balanced distribution of probiotics, high color enhancement, and consumer preference. © 2021 Society of Chemical Industry.

Increase in thermal stability of strawberry anthocyanins with amino acid copigmentation

Copigmentation effects of aspartic acid, proline and valine on individual anthocyanins in strawberry juice (SJ) were investigated during heating at 90, 105 and 150 °C. Aspartic acid increased (4.5-45.6%) total anthocyanin stability at all temperatures, while proline and valine had no effect at 90 °C but reduced (2.2-19.4%) stability at 150 °C. At 90 °C, aspartic acid and valine caused the highest A_max. Evaluating changes in individual anthocyanin contents, A_max, colour density and polymeric colour of SJs together revealed that aspartic acid had copigmentation effects on pelargonidin-3-glucoside and pelargonidin-3-rutinoside, whereas valine on pelargonidin-3-glucoside and cyanidin-3-glucoside. At 105 °C, all amino acids increased (7.9-33.1%) stabilities of pelargonidin-3-glucoside, pelargonidin-3-rutinoside, A_max and colour density all of which together pointed out the copigmentation. At 150 °C, interactions between "aspartic acid-pelargonidin-3-glucoside," "proline-pelargonidin-3-rutinoside" and "valine-pelargonidin-3-rutinoside" resulted in high colour density. Thus, among these amino acids, selection should be based on the heating temperature and anthocyanin profile of the product.

The Colors of Health: Chemistry, Bioactivity, and Market Demand for Colorful Foods and Natural Food Sources of Colorants

There is an increasing consumer demand for natural colors in foods. However, there is a limited number of available natural food sources for use by the food industry because of technical and regulatory limitations. Natural colors are less stable and have less vibrant hues compared to their synthetic color counterparts. Natural pigments also have known health benefits that are seldom leveraged by the food industry. Betalains, carotenoids, phycocyanins, and anthocyanins are major food colorants used in the food industry that have documented biological effects, particularly in the prevention and management of chronic diseases such as diabetes, obesity, and cardiovascular disease. The color industry needs new sources of stable, functional, and safe natural food colorants. New opportunities include sourcing new colors from microbial sources and via the use of genetic biotechnology. In all cases, there is an imperative need for toxicological evaluation to pave the way for their regulatory approval.

Stevia vs. Sucrose: Influence on the Phytochemical Content of a Citrus-Maqui Beverage-A Shelf Life Study

The consumption of sugar-sweetened beverages has been related with the risk of cardiovascular diseases and other pathophysiological situations, such as obesity or diabetes mellitus. Given the increasing awareness on this fact, food industries are developing new products to reduce the amount of added sugar in development of food products development. Accordingly, in the present work, new functional beverages, constituting a dietary source of bioactive phenolics and supplemented with stevia or sucrose, were designed in order to study the influence of the sweetener during processing and shelf-life. This study is of critical for the informed selection of the sweetener based on its effect on the final phytochemical profile of beverages, especially taking into consideration that there are no previous studies on Stevia rebaudiana. Physicochemical features and phytochemical composition, as well as stability of the different beverages concerning these parameters, were evaluated for 90 days during storage under different conditions (refrigeration (4 °C) and room temperature (25 °C) under light or darkness conditions). Physicochemical parameters (pH, titratable acidity, total soluble solids, and color) did not display statistically significant differences between beverages. Storage temperature was the greatest determinant affecting the stability of all the analyzed bioactive compounds (vitamin C, anthocyanins, and flavanones). The main difference between sweeteners was observed in flavanones, which exhibited a higher loss during storage under day light conditions when stevia was added instead of sucrose. In addition, the juices’ colors were rather stable, keeping a reddish coloration and natural appearance throughout the shelf life. Hence, stevia could be considered as an alternative sweetener by the beverage industry.