Free Anthocyanins Research Articles

A study of the oral bioavailability and biodistribution increase of Nanoencapsulation-driven Delivering radiolabeled anthocyanins

Anthocyanins have antioxidant, anti-inflammatory, and anticancer properties but have limited bioaccessibility and bioavailability due to molecular instability in the gastrointestinal tract. This study evaluated the absorption and biodistribution of free and nanoencapsulated radiolabeled anthocyanin (cyanidin-3-O-glucoside). A new methodology was efficiently developed for radiolabeling anthocyanins with Technetium (99mTc-anthocyanins). Then, the anthocyanins were nanoencapsulated through self-assembly using citrus pectin and lysozyme. The nanostructures have a size of 190 nm, a zeta potential of –30 mV, and an invariably spherical and homogeneous morphology. The biodistribution in different tissues, the kinetics of absorption, and molecular visualization by micro single-photon emission computed tomography/computed tomography (µSPECT/CT) showed that the nanoencapsulated anthocyanins are absorbed differently than free anthocyanin in mice. After oral administration, nanostructured anthocyanins were delivered to the blood, spleen, bladder, pancreas, and bone, unlike unencapsulated anthocyanins found only in kidneys and bladder. In silico data indicated the stabilization between compounds in nanocapsules and demonstrated the pH-dependent release of anthocyanins in the intestine. The nanoencapsulation alters the absorption kinetics, increasing the blood’s bioavailability and the organs’ uptake, suggesting an improvement of the biological effects and potential clinical application.

Novel pullulan-sodium alginate film incorporated with anthocyanin-loaded casein-carboxy methyl cellulose nanocomplex for real-time fish and shrimp freshness monitoring

This study fabricated novel smart colorimetric film from pullulan (P) and sodium alginate (SA) incorporated with anthocyanin (ACNs) loaded casein carboxymethylcellulose (CAS-CMC-ACNs) nanocomplex for the freshness monitoring of the fish and shrimp. The ACNs loaded nanocomplex exhibited large particle size (176.902 ± 4.641 nm) than CAS-CMC (155.454 ± 4.152 nm) nanocomplex without ACNs, and can be loaded in P/SA film with uniform distribution. The P/SA film incorporated with CAS-CMC-ACNs nanocomplex had a more compact structure, improved barrier properties, mechanical strength, and thermal stability than P/SA film incorporated with free ACNs, which could be attributed to hydrogen bonding among the components in the film matrix, as confirmed by SEM micrographs and FT-IR. Intriguingly, the composite film exhibited antibacterial effect against gram-negative bacteria E. coli (Escherichia coli) and gram-positive bacteria S. aureus (Staphylococcus aureus) with inhibition zone of 7 ± 0.283 mm and 8.6 ± 0.141 mm, and antioxidant effect. The composite film demonstrated a visible response to CO2 and pH buffer. Furthermore, the composite smart film demonstrated the potential to monitor the freshness of fish and shrimp stored at 25 °C for 24 h via a visual color change from pink to dark grey. The findings revealed that the fabricated film is an effective tool for evaluating the freshness of fish and shrimp.

Dietary Supplementation of Haskap Berry (Lonicera caerulea L.) Anthocyanins and Probiotics Attenuate Dextran Sulfate Sodium-Induced Colitis: Evidence from an Experimental Animal Model.

Haskap berry (Lonicera caerulea L.) is a rich dietary source of anthocyanins with potent anti-inflammatory properties. In this study, isolated haskap berry anthocyanins were encapsulated in maltodextrin and inulin (3:1) by freeze-drying to improve stability and bioavailability. The structural properties of microcapsules, encapsulation yield, efficiency, recovery, and powder retention were evaluated. The microcapsules that exhibited the highest encapsulation efficiency (60%) and anthocyanin recovery (89%) were used in the dextran sulfate sodium (DSS)-induced acute colitis in mice. Thirty-five BALB/c male mice of seven weeks old were divided into seven dietary supplementation groups (n = 5) to receive either free anthocyanins, encapsulated anthocyanins (6.2 mg/day), or probiotics (1 × 109 CFU/day) alone or as combinations of anthocyanin and probiotics. As observed by clinical data, free anthocyanin and probiotic supplementation significantly reduced the severity of colitis. The supplementary diets suppressed the DSS-induced elevation of serum inflammatory (interleukin (IL)-6 and tumor necrosis factor) and apoptosis markers (B-cell lymphoma 2 and Bcl-2-associated X protein) in mice colon tissues. The free anthocyanins and probiotics significantly reduced the serum IL-6 levels. In conclusion, the dietary supplementation of haskap berry anthocyanins and probiotics protects against DSS-induced colitis possibly by attenuating mucosal inflammation, and this combination has the potential as a health-promoting dietary supplement and nutraceutical.

Fabrication of blueberry anthocyanins–rich gels based on the apricot polysaccharides with different esterification degrees

To enhance the stability of anthocyanins under conditions such as light, temperature, and pH, an apricot polysaccharide hydrogel for anthocyanins encapsulation was prepared in this study. Apricot polysaccharides with different DEs were prepared by an alkaline de-esterification method. A gel was prepared by mixing the apricot polysaccharides with CaCl2 to encapsulate the anthocyanins; the encapsulation efficiency reached 69.52 ± 0.31 %. Additionally, the gel exhibited favorable hardness (144.17 ± 2.33 g) and chewiness (64.13 ± 1.53 g). Fourier transform infrared (FTIR) and X-ray diffractometer (XRD) spectra confirmed that the formation of the hydrogel primarily relied on electrostatic interactions and hydrogen bonding. Compared with free anthocyanins, it was also found that the gel-encapsulated anthocyanins had a higher retention rate (RR) under different temperatures and light.

Comprehensive analysis of colloid formation, distribution, and properties of monovarietal red wines using asymmetrical flow field-flow fractionation with online multidetection

Red wine colloids, crucial in determining wine quality and stability, are understudied due to inadequate techniques for studying them effectively in the natural wine environment. Recently, Asymmetrical Flow Field-flow Fractionation (AF4) with online multidetection has emerged as a novel analytical tool for quantifying, fractionating, and characterizing red wine colloids in their native state. This study aimed to characterize the colloidal composition of 24 monovarietal Italian wines produced without filtration, oak contact, fining treatments, malolactic fermentation, macerating enzymes or ageing on yeast lees. AF4 analysis allowed quantification and characterization of wine colloids based on light scattering signal (MALS; gyration radius − Rg), size (hydrodynamic radius – Rh) and absorbance (A280 & A520 nm).The results showed that each wine contained up to five distinct colloids’ populations, varying in size and gyration radii. Despite possessing very similar Rh, most colloids exhibited great differences in compactness, as indicated by their varying Rg values. Comparing the A280 signal of whole wines to those of wines containing only species larger than 5 kDa (considered colloids) allowed to calculate the percentage of molecules involved in colloidal particles assembly, ranging from 1 to 44 % of the total A280 absorbing compounds, reflecting the diversity among wines. The A520 signal indicated the presence of polymeric pigments in the colloidal fraction. Notably, colored colloids all had Rg > 20 nm, indicating their association with other colloidal-forming compounds. This observation led to the conclusion that, apart from free anthocyanins and polymeric pigments, the color of red wines is also due to colloidal particles formed by the latter bound to proteins, with their quantity being highly variable across wines of different origin. These findings, which highlight the fundamental role of proteins in shaping the colloidal status of red wines, were utilized to propose an updated hypothetical model for colloidal aggregation in red wine.

Tea pomace protein-ε-polylysine-anthocyanin composite nanocomplexes: Elucidation of stability, structural properties, and in vitro digestion

Nano-complexation with food proteins has been well recognized to be an effective and safe strategy to improve stability and bioavailability of bioactive compounds. In this study, we applied tea pomace protein (TP) and ε-polylysine (PLL) to load anthocyanins (ACNs), which were further characterized by scanning electron microscopy (SEM), fourier transformed infrared spectroscopy (FTIR), and fluorescence spectrum (FS). The stability and digestive characteristics in vitro were also investigated. The result showed that ACNs-loaded TP-PLL nanocomplexes (TPPLA) formed a dense three-dimension crosslinked network structure by interactions between TP and PLL, while the flakes of ACNs were dispersed in the grid. The interactions between nanocomplexes were analyzed by molecular docking and found to be mainly through hydrogen bonds on polyphenols (C3G) or electrostatic interactions in the hydrophobic cavities of TP (11 S). Compared with free ACNs, The TPPLA nanocomplexes improved its encapsulation efficiency (63.63 ± 0.50 %) and thermal retention rate (70.18 ± 0.98 %). And they presented excellent properties of controlled release during the simulated digestion in vitro. This study is the first to propose developing and utilizing tea pomace protein as a microencapsulated material and the result may promote the successful application of TPPLA nanocomplexes in foods and nutraceuticals.

First Insights on the Bioaccessibility and Absorption of Anthocyanins from Edible Flowers: Wild Pansy, Cosmos, and Cornflower.

Edible flowers are regaining interest among both the scientific community and the general population, not only for their appealing sensorial characteristics but also from the growing evidence about their health benefits. Among edible flowers, those that contain anthocyanins are among the most consumed worldwide. However, little is known regarding the bioaccessibility and absorption of their bioactive compounds upon ingestion. The aim of this work was to explore, for the first time, the behavior of anthocyanin-rich extracts from selected edible flowers under different food processing conditions and after ingestion using simulated digestions, as well as their absorption at the intestinal level. Overall, the results showed that the monoglucoside and rutinoside anthocyanin extracts were less stable under different pH, temperature, and time conditions as well as different digestive processes in the gastrointestinal tract. There was a prominent decrease in the free anthocyanin content after the intestinal phase, which was more pronounced for the rutinoside anthocyanin extract (78.41% decrease from the oral phase). In contrast, diglucoside and rutinoside anthocyanin extracts showed the highest absorption efficiencies at the intestinal level, of approximately 5% after 4 h of experiment. Altogether, the current results emphasize the influence of anthocyanins' structural arrangement on both their chemical stability as well as their intestinal absorption. These results bring the first insights about the bioaccessibility and absorption of anthocyanins from wild pansy, cosmos, and cornflower and the potential outcomes of such alternative food sources.

Gibberellic acid in the ‘Cabernet Sauvignon’ grape: effects on grape cluster morphology and wine quality

‘Cabernet Sauvignon’ is a commonly produced and consumed variety of grapes in Brazil, although late sprouting and flowering negatively affect wine production, hindering the production of elegant and balanced wines, especially in high-altitude regions of Santa Catarina. Therefore, this study sought to evaluate the effects of gibberellic acid (GA3) on reducing and eliminating ‘Cabernet Sauvignon’ grape berry seeds and evaluate the physicochemical parameters of the wine produced in Serra Catarinense. The experiments were conducted in a commercial vineyard. The treatments were 0.0, 40.0, and 80.0 mg L-1 of GA3 in the 2019/20 season and 0.0, 20.0, and 40.0 mg L-1 of GA3 in the 2020/21 season. The applications were performed in full bloom. The characteristics evaluated were cluster weight, berry diameter, berry mass, number of seeds per berry, seed mass, peel:pulp ratio, cluster length, cluster compaction index, rachis mass, and berries per cluster. In both harvests, the zero dose of GA3 was related to greater cluster compaction, berry and cluster mass, and seeds per berry. In the 2019/20 harvest, 80 mg L-1 of GA3 was correlated to must total soluble sugar, wine acidity, must acidity, color parameter at 520 nm, and color intensity. In the last harvest, the color parameters were more correlated with the highest GA3 dose, showing that this growth regulator increased free anthocyanins and total polyphenols. Moreover, 20–80 mg L-1 of GA3 reduced the number and size of seeds but increased the tannin content in one harvest. Bunch compaction, cluster weight, diameter, and berry weight were reduced using GA3. Lastly, 20 and 40 mg L-1 of GA3 increased the total polyphenols and monomeric anthocyanins in the wine.

Thermal degradation of red cabbage (Brassica oleracea L. var. Capitata f. rubra) anthocyanins in a water model extract under accelerated shelf-life testing

Red cabbage (RC) represents a source of anthocyanins acylated with hydroxycinnamic acids (HCA) that are described to enhance their stability. Nevertheless, data about their thermal degradation are still controversial. Our aim was to comprehensively analyse the degradation kinetics of individual RC anthocyanins in a model aqueous extract treated at 40 °C × 30 days to simulate severe but realistic storage conditions. Free anthocyanins and radical-scavenging capacity showed different kinetics. The results confirm the high stability of RC anthocyanins (t1/2: 16.4–18.4 days), although HPLC analyses of each molecule displayed distinct kinetics with t1/2 from 12.6 to 35.1 days. In particular, the sinapoyl acylation negatively affected the stability of the anthocyanins, while the forms monoacylated with glycosyl p-coumaric and ferulic acids exhibited higher stability. In conclusion, our results indicate that acylation is not a prerogative of stability, as this is instead more dependent on specific acylation patterns and the glycosylation of HCA.

Enhanced stability of anthocyanins by cyclodextrin–metal organic frameworks: Encapsulation mechanism and application as protecting agent for grape preservation

Anthocyanins are promising naturally occurring food preservatives for enhancing the quality of food products due to their excellent antioxidant properties. However, their low stability hinders their food packaging application. Here, we propose a facile strategy to achieve the improved stability of anthocyanins encapsulated in γ-cyclodextrin metal-organic frameworks (CD-MOFs) with an in-depth exploration of their structure–property relationships. The adsorbed anthocyanins in CD-MOFs are stabilized by multiple cooperative non-covalent interactions including hydrogen bonding and van der Waals (vdW) interactions as demonstrated by density functional theory (DFT) calculations and spectroscopy analysis. Particularly, by ion-exchange of acetate ions into the pores of CD-MOFs, the resulting CD-MOFs (CD-MOF_OAc) shows a higher anthocyanins adsorption rate with a maximum loading capacity of 83.7 % at 1 min. Besides, CD-MOF_OAc possesses the more effective protecting effect on anthocyanins with at least two-fold enhancement of stability in comparison of free anthocyanins under heating and light irradiation. The anthocyanins encapsulated CD-MOFs films for fruit freshness was validated by the Kyoho experiment. This novel encapsulation system provides a new possibility for the potential use of CD-MOFs as the encapsulating material for anthocyanins in fruit preservation.

Olive pectin-chitosan nanocomplexes for improving stability and bioavailability of blueberry anthocyanins.

Blueberry anthocyanins (ANCs) are natural dietary bioactive colorants, but are unstable and easily degraded. To improve their stability, we constructed the nanocarriers for ANCs through an electrostatic self-assembly method, using chitosan (CS) and olive pectin (PC). Results showed that the CS-ANCs-PC nanocomplexes had nanoscale particle size (81.22±0.44nm), and an encapsulation efficiency of 91.97±0.33% at pH 3.0, 1:1:5 ratio (m/v) of CS: ANCs: PC. Fourier transform infrared and UV-visible spectra demonstrated that ANCs can be embedded into the CS-PC carrier through electrostatic interaction. CS-ANCs-PC with stacked spherical particle structure had good thermal stability by scanning electron microscope and thermogravimetric analysis. Compared with free anthocyanins, CS-ANCs-PC possessed better DPPH· and ·OH scavenging activities, stronger environmental stability, and better targeted release in vitro digestion. This study may provide an important fundamental basis for improving the stability of anthocyanins in the blueberry industry.

Development and characterization of pH responsive sodium alginate hydrogel containing metal-phenolic network for anthocyanin delivery

Favorable hydrogels can be used as a material to deliver bioactive molecules and improve the stability of bioactive substances, while their safety needs to be improved. In this study, protocatechuic acid (PCA) and Fe3+ were rapidly self-assembled to form a metal-phenolic network under different pH conditions, and then sodium alginate (SA) was added to prepare the SA/PCA/Fe hydrogel without adding other chemical reagents. The structural characteristic of SA/PCA/Fe hydrogel was characterized by infrared spectroscopy, X-ray diffraction analysis and scanning electron microscopy. The results showed that the structures of SA/PCA/Fe hydrogels prepared at different pH values were significantly different. The texture analysis, water-holding measurement and rheological analysis indicated that the SA/PCA/Fe hydrogel showed higher gel strength, water holding capacity and storage modulus. Thermogravimetric analysis illuminated that the SA/PCA/Fe hydrogel enhanced the thermal stability of free anthocyanins through encapsulating anthocyanins. Moreover, in vitro simulated digestion experiment revealed that SA/PCA/Fe hydrogel could control the release of anthocyanins in the simulated gastrointestinal tract. To sum up, this present study might provide a safer and feasible way for the delivery of bioactive substances.

High-Stability Bi-Layer Films Incorporated with Liposomes @Anthocyanin/Carrageenan/Agar for Shrimp Freshness Monitoring

High-stability bi-layer films were prepared by incorporating anthocyanin-loaded liposomes into carrageenan and agar (A-CBAL) for non-destructive shrimp freshness monitoring. The encapsulation efficiency of the anthocyanin-loaded liposomes increased from 36.06% to 46.99% with an increasing ratio of lecithin. The water vapor transmission (WVP) of the A-CBAL films, with a value of 2.32 × 10-7 g · m-1 · h-1 · pa-1, was lower than that of the film with free anthocyanins (A-CBA). The exudation rate of the A-CBA film reached 100% at pH 7 and pH 9 after 50 min, while the A-CBAL films slowed down to a value lower than 45%. The encapsulation of anthocyanins slightly decreased the ammonia sensitivity. Finally, the bi-layer films with liposomes successfully monitored shrimp freshness with visible color changes to the naked eye. These results indicated that films with anthocyanin-loaded liposomes have potential applications in high-humidity environments.

High power ultrasound treatment of crushed grapes: Beyond the extraction phenomena

The treatment of white and red crushed grapes by high power ultrasounds (US) represents an emerging technology in winemaking. In 2019, it was officially recognized by OIV through the resolution n°616-2019, and it was also approved by European Union in January 2022. The US effect on extraction mechanisms was widely studied, but more researches are needed to better understand the ultrasound effect on some specific classes of grape compounds. This research aimed to highlight at laboratory scale some specific effects of ultrasounds on some key compounds of white and red grapes. The samples were sonicated at different frequency (20-30 kHz), time (1-10 min), and power (30-90%) technological conditions used in maceration, to obtain valuable information on potential technological transferability. Valuable results were obtained regarding the release of thiols from their precursors, and the reactivity changes of unstable proteins of white wines. The experimental trails on red grape varieties allowed a maintenance of free anthocyanins and no degradative effects were highlighted. Significant and valuable effects were determined also on the tannin polymerization, with an astringency decrease. The sonication treatment of crushed grapes showed several chemical effects that contribute to decreasing the winemaking inputs and preserving the wine quality. The process conditions must be managed related to grape variety and ripeness for a precision winemaking.

Anthocyanins from Aronia melanocarpa Bound to Amylopectin Nanoparticles: Tissue Distribution and In Vivo Oxidative Damage Protection.

The in vivo applications of anthocyanins are limited by their instability. Nano-encapsulation using amylopectin nanoparticles (APNPs) stabilizes anthocyanins to deliver them to tissues to ameliorate their physiological functions. Herein, rats are fed four Aronia melanocarpa anthocyanins encapsulated with APNPs, and their subsequent distributions and bioactivity in nine tissues are revealed using UHPLC-MS. Among digestive tissues, the concentration of the APNP-protected cyanidin 3-O-arabinoside in the stomach is 134.54% of that of the free anthocyanin, while among non-digestive tissues, the APNP-protected cyanidin 3-O-glucoside concentration in the lungs improved by 125.49%. Concentration maxima "double peaks" in the liver and kidney arise from different modes of transport. Sustained release of anthocyanins from anthocyanin-APNPs and stable concentration curves suggest controlled delivery, with most APNPs consumed in the digestive system. APNPs did not affect the overall anthocyanin absorption time or tissues. The superoxide dismutase and malondialdehyde concentrations indicate that APNPs enhance the oxidative damage protection in vivo.

Early Basal Leaf Removal at Different Sides of the Canopy Improves the Quality of Aglianico Wine.

It is well known that the early removal of basal leaves is a viticultural practice adopted to improve the exposure of clusters to direct sunlight and UV radiation and increase the phenolic compounds and anthocyanin concentration in the berries. The aim of this work was to study the influence of early basal leaf removal on Aglianico wines produced in the Apulia region (southern Italy) during three consecutive seasons. Three vine treatments were carried out, where 100% of the cluster-zone leaves on the north, south and both sides of the canopy were removed. Undefoliated plants were used as a control. The effect of the treatments on the basic chemical parameters, phenol content and volatile composition of wines was investigated using WineScan FT-MIR, spectrophotometry, HPLC-DAD and SPME-GC/MS. Early defoliation increased the amounts of flavonoids (+35–40%), anthocyanins (+15–18%), total polyphenols (+10%), antioxidant activity (+8–14%) and colour intensity (+10%), especially when leaf removal was applied on the south side. Moreover, leaf removal led to a 40% increase in free anthocyanins when applied on the south side of the canopy, while a 24% increase was observed when applied to the north side and 21% when applied to the north and south sides. A negative effect was observed on volatile compounds, which decreased by about 18, 14 and 13% when the treatment was applied on the north, north-south and south sides of the canopy, respectively. In conclusion, early leaf removal treatments allow for the modulation of the phenolic and volatile concentrations of Aglianico wines.

Impact of rutin and buckwheat (Fagopyrum esculentum) extract applications on the volatile and phenolic composition of wine

The aim of this research is to study the possibility of increasing the quality of red wins made with the Monastrell grape variety. A methodology was established to improve the concentration levels of polyphenol and aroma in these wines. Among flavonoids, the copigmenting effect of rutin stands out, and was tested in both winery and field applications. Buckwheat extract (Fagopyrum esculentum), in which rutin is the main flavonoid, may be of interest for viticulture given its biological activity.This paper focuses on researching the effect of applying the prefermentative vegetable extract of buckwheat (Fagopyrum esculentum) on the concentration of polyphenols and aroma compounds in vineyards. Simultaneously, a study was carried out to compare the effect of pure copigment (rutin) when applied in vineyards and cellars. Traditional vinification was done, plus prefermentative cold maceration.The application of buckwheat extract, and rutin extract to a lesser extent, to Monastrell grapes increased the concentration of malvidin and other anthocyanins, and total anthocyanins. After 12-month storage, no differences were observed in the percentage of copigmented, polymerised and free anthocyanin, the total polyphenol concentration, and the tannin quality parameters like DMACH (aldehyde p-dimethylaminoacimaldehyde) and the Gelatin Index. The concentrations of diethyl succinate, 2 phenylethyl acetate, vanillin and ethyl octanoate increased, while other compounds decreased when the copigment was added. The maceration technique followed during the vinification process had very little effect on polyphenolic compounds. The prefermentative maceration slightly increasing the concentration of total polyphenols, but had no effect on the parameters related to colour, anthocyanin concentration, nature of anthocyanins, their binding state or tannin quality parameters. The results showed that cold prefermentation maceration increased the concentration of some volatile compounds, including alcohols and esters, which should be considered important contributors to Monastrell wine aroma.The combination of the applying buckwheat extract and pure rutin together, and prefermentative cold maceration, positively affects the polyphenolic concentration and increases the concentration of quality volatile compounds.

Intelligent packaging films incorporated with anthocyanins-loaded ovalbumin-carboxymethyl cellulose nanocomplexes for food freshness monitoring

An intelligent colorimetric film was prepared to monitor mushrooms freshness by incorporating anthocyanin-loaded ovalbumin-carboxymethyl cellulose nanocomplexes (OVA-CMC-ACNs) into corn starch/polyvinyl alcohol matrix. The results showed that ACNs could be loaded into OVA-CMC nanocomplexes with larger particle size and more uniform size distribution. The structure, physical properties, colorimetric response and practical application of films were studied. Compared with SP/ACNs film incorporation of free anthocyanins, SP/OVA-CMC-ACNs film had denser structure, higher mechanical and water barrier properties, and better thermal stability, which were related to the hydrogen bond among film components by FT-IR. The SP/OVA-CMC-ACNs film showed obvious colorimetric response in CO2 gas and pH buffer. The successful applications of intelligent film for the freshness monitoring of mushrooms. The intelligent film could monitor the freshness of mushrooms during the storage by visual color change from purple to pink. These results indicated that prepared SP/OVA-CMC-ACNs film have great application potential in intelligent food packaging.

Quality Characteristics of Senior-Friendly Gelatin Gels Formulated with Hot Water Extract from Red Maple Leaf as a Novel Anthocyanin Source.

The objectives of this study were to evaluate antioxidant capacity of hot water extract from red maple leaf with different extraction times (experiment I) and to determine their impacts on color, free anthocyanin content, and hardness of gelatin gels (experiment II). In experiment I, hot water extraction time (30, 60, 120, 180, and 360 min at 60 °C) was fixed as a main effect. The different extraction times had no impacts on total polyphenol content and DPPH radical scavenging activity (p > 0.05). However, extraction time for 360 min could decrease anthocyanin content as well as ferric reducing antioxidant power (p < 0.05). In experiment II, 6%, 18%, and 30% gelatin gels were prepared without/with red maple leaf extract (1000 mg/L). The red maple leaf extract significantly increased redness, yellowness, and hardness, but decreased free anthocyanin content. Such impacts were obviously observed at high gelatin concentration. Thus, red maple leaf extract could be a novel anthocyanin source for improving antioxidant capacity and reddish color of gelatin gels. However, the addition amount of red maple leaf extract may be limited in the development of senior-friendly jelly food for soft texture in that it could increase the hardness of the gelatin gel.

Cranberry (Vaccinium macrocarpon) Juice Precipitate Pigmentation Is Mainly Polymeric Colors and Has Limited Impact on Soluble Anthocyanin Loss.

Anthocyanins degrade in fruit juice during storage, reducing juice color quality and depleting the health-promoting components of juice. Common water-soluble products of anthocyanins’ chemical degradation are known, but little is known about the contribution of the insoluble phase to loss processes. Cranberry juice and isolated anthocyanins were incubated at 50 °C for up to 10 days to determine polyphenol profiles and degradation rates. Anthocyanin-proanthocyanidin heteropolymers were analyzed via Matrix Assisted Laser Desorption/Ionization (MALDI)- Time of Flight (TOF) Mass Spectrometry (MS). Formation of soluble protocatechuic acid accounted for 260 ± 10% and insoluble materials for 80 ± 20% of lost soluble cyanidin-glycosides in juice, over-representations plausibly due to quercetin and (epi)catechin in cranberry juice and not observed in the values of 70 ± 20% and 16 ± 6% in the purified anthocyanin system. Loss processes of soluble peonidin-glycosides were better accounted for, where 31 ± 2% were attributable to soluble vanillic acid formation and 3 ± 1% to insoluble materials in cranberry juice and 35 ± 5% to vanillic acid formation and 1.6 ± 0.8% to insoluble materials in the purified anthocyanin system. Free anthocyanins were below quantifiable levels in precipitate, implying most anthocyanins in precipitate were polymeric colors (PCs). PCs in the precipitate included cyanidin- and peonidin-hexosides and -pentosides covalently bonded to procyanidins. Therefore, formation of cranberry juice precipitate does not deplete a large portion of soluble anthocyanins; rather, the precipitate’s pigmentation results from PCs that are also present in the soluble phase.