Smart labels based on polyvinyl alcohol incorporated with chitosan nanoparticles loaded with grape extract: Functionality, stability and food application.

Anthocyanins (ACNs) are natural compounds with potential applications due to their colorimetric response to pH. Due to their sensitivity to various environmental factors, nanoencapsulation with biopolymers is a successful strategy for stabilizing ACNs. In this work ACNs were extracted from grape skins and encapsulated into chitosan (CS) nanoparticles by ionic gelation using sodium tripolyphosphate (TPP) as a cross-linking agent. CS nanoparticles loaded with ACNs had particle sizes between 291 and 324 nm and polydispersity index around 0.3. The encapsulation efficiency of ACNs was approximately 60 %; and encapsulated anthocyanins (ACN-NPs) exhibited color change properties under different pH conditions. pH-sensitive labels based on polyvinyl alcohol (PVA) were prepared by the casting method. The effect of incorporating ACN-NPs on the physical, structural, and pH-sensitive properties of PVA labels was evaluated, and its application as shrimp freshness indicator was studied. The nanoencapsulation protected ACNs against heat and light treatments, preserving the original purple color. When applying the label, visible changes from red to blue until reaching yellow were observed with the change in the quality of the shrimp at the refrigeration temperature. The results suggest that PVA labels containing ACNs encapsulated in C-NPs can be used as smart packaging labels in the food industry.

Esterification of black bean anthocyanins with unsaturated oleic acid, and application characteristics of the product.

Esterification of anthocyanins with saturated fatty acids have been widely investigated, while that with unsaturated fatty acids is little understood. In this study, crude extract (purity âˆ¼ 35 %) of cyanidin-3-O-glucoside (C3G) from black bean seed coat was utilized as reaction substrate, and enzymatically acylated with unsaturated fatty acid (oleic acid). Optimization of various reaction parameters finally resulted in the highest acylation rate of 54.3 %. HPLC-MS/MS and NMR analyses elucidated the structure of cyanidin-3-O-glucoside-oleic acid ester (C3G-OA) to be cyanidin-3-O-(6″-octadecene)-glucoside. Introduction of oleic acid into C3G improved the lipophilicity, antioxidant ability, and antibacterial activity. Further, the color and substance stability analyses showed that the susceptibility of C3G and C3G-OA to different thermal, peroxidative, and illuminant treatments were highly pH dependent, which suggested individual application guidelines. Moreover, C3G-OA showed lower toxicity to normal cell (QSG-7701) and better inhibitory effect on the proliferation of HepG2 cells than C3G, which indicated its potential anti-tumor bioactivity.

Sustainable green extraction of anthocyanins and carotenoids using deep eutectic solvents (DES): A review of recent developments.

Recently, deep eutectic solvents (DES) have been extensively researched as a more biocompatible and efficient alternative to conventional solvents for extracting pigments from natural resources. The efficiency of DES extraction for the anthocyanin and carotenoid can be enhanced by microwave-assisted extraction (MAE) and/or ultrasound-assisted extraction (UAE) techniques. Apart from the extraction efficiency, the toxicity and recovery of the pigments and their bioavailability are crucial for potential applications. A plethora of studies have explored the extraction efficiency, toxicity, and recovery of pigments from various natural plant-based matrices using DES. Nevertheless, a detailed review of the deep eutectic solvent extraction of natural pigments has not been reported to date. Additionally, the toxicity, safety, and bioavailability of the extracted pigments, and their potential applications are not thoroughly documented. Therefore, this review is designed to understand the aforementioned concepts in using DES for anthocyanin and carotenoid extraction.

Multipurpose arrowroot starch films with anthocyanin-rich grape pomace extract: Color migration for food simulants and monitoring the freshness of fish meat.

Extraction of anthocyanins from grape pomace, is a way of valuing these abundant by-products with low added value. Its integration into films may allow it to be used in bioactive packaging, which creates new color and solubility properties for food and smart food packaging which tracks the freshness of fish. Films of arrowroot starch added with different concentrations of grape pomace extract (GPE) were flexible to handle, reddish and presented a high content of anthocyanins. The water vapor permeability increased by 17 %, while the tensile strength of arrowroot starch film decreased by 79 % with the addition of 40 % GPE. The addition of GPE increased the solubility of the starch film in aqueous and lipid food simulants by 121 and 119 %. The GPE pigment preferentially migrated to the aqueous simulant due to the hydrophilic nature of anthocyanins and starch. The GPE film showed distinguishable color changes in different pH buffer solutions from pink at pH 2 to light blue at pH 7 and slightly yellowish green at pH 10. When the composite films were monitored for fish meat freshness, the change in color of the film from reddish pink to slightly green after 96 h of storage at 25 °C was evident.

Valorization and protection of anthocyanins from strawberries (Fragaria×ananassa Duch.) by acidified natural deep eutectic solvent based on intermolecular interaction.

This study introduces an innovative approach for the valorization and protection of anthocyanins from 'Benihoppe' strawberry (Fragaria × ananassa Duch.) based on acidified natural deep eutectic solvent (NADES). Choline chloride-citric acid (ChCl-CA, 1:1) was selected and acidified to enhance the valorization and protection of anthocyanins through hydrogen bond. The optimal conditions (ultrasonic power of 318 W, extraction temperature of 61 °C, liquid-to-solid ratio of 33 mL/g, ultrasonic time of 19 min), yielded the highest anthocyanins of 1428.34 µg CGE/g DW. UPLC-Triple-TOF/MS identified six anthocyanins in acidified ChCl-CA extract. Stability tests indicated that acidified ChCl-CA significantly increased storage stability of anthocyanins in high temperature and light treatments. Molecular dynamics results showed that acidified ChCl-CA system possessed a larger diffusion coefficient (0.05 m2/s), hydrogen bond number (145) and hydrogen bond lifetime (4.38 ps) with a reduced intermolecular interaction energy (-1329.74 kcal/mol), thereby efficiently valorizing and protecting anthocyanins from strawberries.

Study on preservation and monitoring effect of sodium alginate-konjac glucomannan films loaded with tea polyphenols and Lycium ruthenicum anthocyanins.

To investigate the efficacy of sodium alginate-konjac glucomannan (SA-KGM) films with anthocyanins (LRA) and tea polyphenols (TP) in meat, beef and grass carp were selected as representative meat products for preservation and freshness monitoring experiments at 4 °C. Concurrently, storage experiments of the films were conducted in this controlled environment. The results of the storage experiment showed that the films delayed meat spoilage by 2-4 days, nearly doubling the preservation time compared to the blank control. Additionally, the film exhibited significant capability to monitor the spoilage process of beef and grass carp. It was revealed by curve fitting analysis that there was a significant correlation between the color change of the film and the spoilage index of the meat. Throughout the storage experiment with the film, it was observed that moisture significantly influenced the microstructure and bonding situation of the films, thereby impacting their mechanical and barrier properties. However, the films were still able to maintain satisfactory physicochemical properties in general. The above findings were crucial in guiding the promotion of the film within the food preservation industry.

Preparation and evaluation of smart food packaging films with anthocyanin Sardasht black grape based on Astragalus gummifer and chitosan nanoparticles.

A new and green development in the field of food packaging is the use of colorimetric films containing anthocyanins, which not only can respond to food spoilage but also have no environmental risk and help the environment full of unacceptable and polluted substances created by humans. In this research, a completely natural film (GCNG) was made using natural materials including tragacanth gummifer (G), chitosan nanoparticles (C), and an extract containing anthocyanins of a type of wild grape called Sardasht black (G) with Alumina nanoparticles (N) for use in food packaging. This biodegradable film (GCNG) presented relatively wide color differences from red to blue in different buffer solutions (pH 2-12), which was clearly observed by the naked eye. Sardasht black grape extract contains large amounts of anthocyanins and antioxidants that can be extracted and used in the preparation of packaging films. The properties of prepared films, including mechanical properties, permeability to water vapor, solubility, swelling, as well as antimicrobial properties were checked by measuring the diameter of the diffusion area by agar disk test. GCNG films showed strong antioxidant activity and good antibacterial activity against E. coli and S. aureus. The results suggested this film has promising potential as an active and smart packaging material for applications in the food industry.

Effect of ultrasonic modification on the binding ability of pectin to anthocyanin.

BACKGROUND: Pectin was considered as a potential candidate to improve the thermal stability of anthocyanins, and the binding ability of pectin to anthocyanins was influenced by its structure. In this study, sunflower pectins, modified by ultrasound (40 kHz) for different periods of time, were prepared and used to bind with anthocyanins, extracted from purple sweet potato. RESULTS: Characterization and thermal stability of pectin-anthocyanin complexes were investigated. The ultrasonic modification of pectin resulted in many changes in pectin chemical structure, including degradation of neutral sugar side chains, breakage of methoxyl groups, and increased molecular flexibility. Extension of ultrasonic modification time led to greater changes in pectin chemical structure. Analysis of the binding ability, as determined by Fourier transform infrared spectroscopy and molecular dynamics simulations, revealed that the interaction between pectin and anthocyanins was driven by hydrogen bonding, electrostatic interaction, and hydrophobic interaction. Pectins with different ultrasonic modification times bound with anthocyanins to different extents, mainly resulting from an increase in the number of hydrogen bonds. According to high-performance liquid chromatographic analysis, during heating at 90 °C the stronger the binding ability of pectin and anthocyanin complex, the better was its thermal stability. CONCLUSION: Ultrasonic modification of pectin could effectively enhance its binding ability to anthocyanin. © 2023 Society of Chemical Industry.

Influence of time-temperature in the antioxidant activity, anthocyanin and polyphenols profile, and color of Ardisia compressa K. extracts, with the addition of sucrose or citric acid.

The objective of this study was to analyze and optimize the influence of heating time and citric acid (CA) or sucrose addition of Ardisia compressa K. extracts on phenolic compounds (TPC), monomeric anthocyanins (MAA), antioxidant activity (TAC), color density (CD), and hue tint (HT), using a full factorial design. Extractions were performed: temperature (25, 50, or 70 °C), time (15, 30, 60, or 90 min), CA (0.0 or 0.02 g), and sucrose (0.0 or 5.0 g). HPLC-DAD-ESI-MS was conducted in extracts without additives and with the addition of CA (0.02 g) or sucrose (5.0 g), at 25, 50, or 70 °C for 15 min. CA-added extracts showed maximum TPC, MAA, TAC (DDPH and ABTS assays), and CD values, with the lowest HT values. Malvidin 3-O-galactoside and myricetin-O-hexoside were the predominant anthocyanin and non-anthocyanin polyphenols. Time, temperature, and solute influenced the optimized extraction of TPC, MAA, anthocyanins, TAC, CD, and HT.

The Chemical Profile, Antioxidant, and Anti-Lipid Droplet Activity of Fluid Extracts from Romanian Cultivars of Haskap Berries, Bitter Cherries, and Red Grape Pomace for the Management of Liver Steatosis.

This study aimed to investigate, for the first time, the chemical composition and antioxidant activity of fluid extracts obtained from three Romanian cultivars of haskap berries (Lonicera caerulea L.) var. Loni, bitter cherries (Prunus avium var. sylvestris Ser.) var. Silva, and pomace from red grapes (Vitis vinifera L.) var. Mamaia, and their capacity to modulate in vitro steatosis, in view of developing novel anti-obesity products. Total phenolic, flavonoid, anthocyanin, and ascorbic acid content of fluid extracts was spectrophotometrically assessed and their free radical scavenging capacity was evaluated using Trolox Equivalent Antioxidant Capacity (TEAC) and free 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition assays. The Pearson coefficients showed a moderate correlation between the antioxidant activity of fluid extracts and their phenolic content, but a strong correlation between anthocyanin and ascorbic acid content. HPLC analysis identified and quantified the main phenolic compounds of chlorogenic and syringic acid, catechin, and glycosylated kaempferol, apigenin, and quercetin, in variable proportions. An in vitro experimental model of steatosis was developed in HepG2 hepatocytes treated with a mixture of free fatty acids. Cell culture analyses showed that cytocompatible concentrations of fluid extracts could significantly reduce the lipid accumulation and inhibit the reactive oxygen species, malondialdehyde, and nitric oxide secretion in stressed hepatocytes. In conclusion, these results put an emphasis on the chemical compounds' high antioxidant and liver protection capacity of unstudied fluid extracts obtained from Romanian cultivars of bitter cherries var. Silva and pomace of red grapes var. Mamaia, similar to the fluid extract of haskap berries var. Loni, in particular, the positive modulation of fat deposition next to oxidative stress and the lipid peroxidation process triggered by fatty acids in HepG2 hepatocytes. Consequently, this study indicated that these fluid extracts could be further exploited as hepatoprotective agents in liver steatosis, which provides a basis for the further development of novel extract mixtures with synergistic activity as anti-obesity products.

Enhancing the stability of natural anthocyanins against environmental stressors through encapsulation with synthetic peptide-based gels.

The instability of anthocyanin to environmental stressors severely limits its applications as a natural bioactive pigment. To overcome these limitations, this proof-of-concept study utilizes the high biocompatibility of peptide molecules and the unique gel microstructure to develop innovative peptide-based gels. Characterization of the gels was conducted through AFM, SEM, rheological analysis, and CD spectrum. These analyses confirmed the fibrous mesh structure and impressive mechanical strength of the peptide-based gels. The cytotoxicity evaluation using MTT and hemolysis analysis showed high biocompatibility. Encapsulation efficiency analysis and fluorescence microscopy images demonstrated successful and efficient encapsulation of anthocyanins in all four peptide-based gels, with uniform distribution. Moreover, systematic investigations were conducted to assess the impact of peptide-based gels on the stability of natural anthocyanins under environmental stressors such as temperature, pH variations, and exposure to metal ions. Notably, the results revealed a significant enhancement in stability, including improved long-term storage and antioxidant activity. In conclusion, this study successfully developed four novel peptide-based gels that effectively protect natural anthocyanins from environmental stressors, highlighting their potential in various fields such as food and biology.

Effects of sunflower pectin on thermal stability of purple sweet potato anthocyanins at different pH.

The present study aimed to examine the impact of sunflower pectin (SFP) on the thermal stability and antioxidant activity of purple sweet potato anthocyanins (PSPA) at varying pH levels. It was observed that the pH value significantly influenced the ability of pectin to protect anthocyanins from thermal degradation, which was found to be associated with the rate of binding between PSPA and SFP. The binding rate of PSPA-SFP was observed to be highest at pH 4.0, primarily due to the influence of electrostatic interaction and hydrogen bonding. Monoacylated anthocyanins exhibited a binding rate approximately 2-4 % higher than that of diacylated anthocyanins. The PSPA-SFP demonstrated its highest thermal stability at pH 4.0, with a corresponding half-life of 14.80 h at 100 °C. Molecular dynamics simulations indicated that pectin had a greater affinity for the flavylium cation and hemiketal form of anthocyanins. The antioxidant activity of anthocyanins in PSPA and PSPA-SFP increased with increasing pH, suggesting that anthocyanins at high pH had higher antioxidant activity than anthocyanins at low pH.

Biological stabilization of natural pigment-phytochemical from poppy-pollen (Papaver bracteatum) extract: Functional food formulation.

In this study, poppy-pollen extract (as a novel source of pigment and natural phytochemical) was microencapsulated. The spray-drying process maintained the encapsulation efficiency (EE) of phenolic (84-93%), anthocyanins (71-83%), and also antioxidant activity of extract in inhibiting DPPH (68-80%), ABTS (74-95%), OH (63-74%) radicals and reducing power (84-95%). The results of the Photo- and thermal (40-70˚C) stability of the bioactive compounds (TPC and TAC) indicated the thermal degradation and decomposition of particles' surface compounds during storage. The chemical (FTIR) and morphological analyses respectively revealed the insertion of extract compounds in the carrier matrix and the production of healthy particles with wrinkled structures. An increase in the carrier concentration elevated physical-stability, maintained structural properties, reduced hygroscopicity, and formed liquid/solid bridges or deliquescence phenomenon. The evaluation of the color histogram of the fortified gummy-candies indicated the usability of the spray-dried PP extract in producing an attractive red color with high sensory perception.

Inhibitory Potential of Different Bilberry (Vaccinium myrtillus L.) Extracts on Human Salivary α-Amylase.

Recently, consumer preferences for bilberries have increased markedly. This fact is probably related to their natural constituents, such as phenolic compounds including anthocyanins and tannins, as well as the vitamins and minerals they contain. Phenolic compounds are known for their numerous beneficial effects on human health. Moreover, bilberry fruits have been shown to inhibit the activity of carbohydrate hydrolyzing enzymes, which can significantly decrease the postprandial increase in blood glucose levels. Thus, the aim of the present study is to investigate the inhibitory effect of Vaccinium myrtillus L. extracts on key enzyme α-amylase, linked to type 2 diabetes. No data have been published on the inhibitory properties of Vaccinium myrtillus L. fruits growing wild in Bulgaria against carbohydrate enzymes. Bilberry extracts were analyzed for total polyphenols, total anthocyanin content, antioxidant activity and their inhibitory properties against α-amylase. The contents of flavonols, anthocyanins and stilbenes were determined by HPLC analysis. The identified flavonols in the analyzed bilberry extracts were mainly represented by quercetin derivatives as rutinoside. The predominant anthocyanins for both aqueous and organic solvents were delphinidin-3-galactoside and malvidin-3-glucoside. The results revealed that bilberry extracts are effective inhibitors of α-amylase, with IC50 values from 20.8 to 194.8 µg GAE/mL. All the samples proved to have antioxidant activity measured by three different in vitro assays (FRAP, CUPRAC and DPPH). The inhibitory properties of V. myrtillus L. extracts may provide a new direction in the development and research of new pharmaceuticals for the suppression of postprandial hyperglycemia in diabetic patients.

Improving Blueberry Anthocyanins' Stability Using a Ferritin Nanocarrier.

Blueberries are fruits known for their high level of anthocyanins, which have high nutritional value and several biological properties. However, the chemical instability of anthocyanins is one of the major limitations of their application. The stability of blueberry anthocyanin extracts (BAEs) encapsulated in a ferritin nanocarrier was investigated in this study for several influencing parameters, including pH, temperature, UV-visible light, redox agents, and various metal ions. The outcomes supported the positive role of protein nanoparticles in enhancing the stability of blueberry anthocyanins by demonstrating that the stability of encapsulated BAE nanoparticles with ferritin carriers was significantly higher than that of free BAEs and a mixture of BAEs and ferritin carriers. This study provides an alternative approach for enhancing blueberry anthocyanin stability using ferritin nanocarrier encapsulation.

Tissue lipidomics, network pharmacology, and molecular docking to explore the therapeutic mechanism of anthocyanins from Lycium ruthenicum Murr. against gouty arthritis.

Lycium ruthenicum Murr. (LR) has long been used as a unique nutritional and medicinal food to treat various diseases such as gouty arthritis. However, although recently the literature has focused on the protective roles of LR anthocyanins on gouty arthritis, there is no relevant research from a holistic perspective of lipid metabolism to study their anti-gout effects. In this study, a combined tissue lipidomics, network pharmacology, and molecular docking approach was performed to investigate the intervention mechanism of LR anthocyanins against a monosodium urate (MSU)-induced gout mouse model. 54 gout-related lipid markers were identified via lipidomic profiling of the mouse knee joint, including glycerophospholipids, sphingolipids, glycerolipids, and plasmalogens. Integrating with pathway analysis, network pharmacology, and molecular docking, the potential targets of LR anthocyanins for treating gouty arthritis were predicted, while pathways in cancer, prostate cancer, sphingolipid signaling, choline metabolism in cancer, arachidonic acid metabolism, and ovarian steroidogenesis were involved as shared critical pathways of lipidomic analysis and network pharmacology. Furthermore, the binding sites and patterns of 3 active components and 4 core targets with the lowest binding energies were explored. Western blotting was finally used to verify the expression levels of 4 core proteins: MMP2, MMP9, MAP2K1, and MAPK14. These results provide new insights into our understanding of gouty arthritis and the anti-gout mechanism of LR anthocyanins.

Pectin-interactions and the digestive stability of anthocyanins in thermal and non-thermal processed strawberry pulp.

This study investigated the digestive stability of anthocyanins (ACNs) and their interaction with three pectin fractions-water-soluble pectin (WSP), cyclohexanetrans-1,2-diamine tetra-acetic acid-soluble pectin (CSP), and sodium carbonate-soluble pectin (NSP)-in strawberry pulp processed by pasteurization (PS), ultrasound (US), electron beam (EB) irradiation, and high pressure (HP). Compared with the control group, the ACNs content increased to the highest level (312.89 mg/mL), but the retention rate of ACNs in the simulated intestine decreased significantly after US treatment. The monosaccharide compositions indicated that the WSP and CSP possessed more homogalacturonan (HG) domains than the NSP, which contains more rhamngalacturonan-I (RG-I) domains. The microstructure of US-treated pectin was damaged and fragmented. Comprehensive analysis showed that the retention rate of ACNs was closely related to the pectin structure, primarily reflected by the degree of linearity and the integrity of structure. These results revealed the structure-activity relationship between ACNs and pectin during pulp processing.

Hibiscus acetosella: An Unconventional Alternative Edible Flower Rich in Bioactive Compounds.

The interest in the consumption of edible flowers has increased since they represent a rich source of bioactive compounds, which are significantly beneficial to human health. The objective of this research was to access the bioactive compounds and antioxidant and cytotoxic properties of unconventional alternative edible flowers of Hibiscus acetosella Welw. Ex Hiern. The edible flowers presented pH value of 2.8 ± 0.00, soluble solids content of 3.4 ± 0.0 °Brix, high moisture content of about 91.8 ± 0.3%, carbohydrates (6.9 ± 1.2%), lipids (0.90 ± 0.17%), ashes (0.4 ± 0.0%), and not detectable protein. The evaluation of the scavenging activity of free radicals, such as 2,2-diphenyl-1-picryl-hydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), of the flower extract was better than the results observed for other edible flowers (507.8 ± 2.7 µM TE and 783.9 ± 30.8 µM TE, respectively) as well as the total phenolic composition (TPC) value (568.8 ± 0.8 mg GAE/g). These flowers are rich in organic acids and phenolic compounds, mainly myricetin, and quercetin derivatives, kaempferol, and anthocyanins. The extract showed no cytotoxicity for the cell lineages used, suggesting that the extract has no directly harmful effects to cells. The important bioactive compound identified in this study makes this flower especially relevant in the healthy food area due to its nutraceutical potential without showing cytotoxicity.

Exopolysaccharide riclin and anthocyanin-based composite colorimetric indicator film for food freshness monitoring.

Food freshness monitoring is vital to ensure food safety. Recently, packaging materials incorporating pH-sensitive films have been employed to monitor the freshness of food products in real time. The film-forming matrix of the pH-sensitive film is essential to maintain the desired physicochemical functions of the packaging. Conventional film-forming matrices, such as polyvinyl alcohol (PVA), have drawbacks of low water resistance, poor mechanical properties, and weak antioxidant ability. In this study, we successfully synthesise PVA/riclin (P/R) biodegradable polymer films to overcome these limitations. The films feature riclin, an agrobacterium-derived exopolysaccharide. The uniformly dispersed riclin conferred outstanding antioxidant activity to the PVA film and significantly improved its tensile strength and barrier properties by forming hydrogen bonds. Purple sweet potato anthocyanin (PSPA) was used as a pH indicator. The intelligent film with added PSPA provided robust surveillance of volatile ammonia and changed its color within 30 s in the pH range of 2-12. This multifunctional colorimetric film also engendered discernible color changes when the quality of shrimp deteriorated, demonstrating its great potential as an intelligent packaging material to monitor food freshness.

Development of intelligent and active potato starch films based on purple corn cob extract and molle essential oil.

The present study aims to develop an active and "intelligent" film that uses potato starch as a polymeric matrix, anthocyanins from purple corn cob as a natural dye, and molle essential oil as an antibacterial compound. The color of anthocyanin solutions is pH-dependent, and the developed films show a visual color change from red to brown after immersion in solutions with pH values ranging from 2 to 12. SEM and FTIR analyses suggested that anthocyanins have favorable dispersibility and good compatibility with the starch-glycerol matrix. The study found that both anthocyanins and molle essential oil significantly enhanced the ultraviolet-visible light barrier performance. Tensile strength, elongation at break, and elastic modulus reached values of 3.21 MPa, 62.16 %, and 12.87 MPa, respectively. The biodegradation rate in vegetal compost also accelerated during the three-week period, achieving a weight loss of 95 %. Moreover, the film presented an inhibition halo for Escherichia coli, indicating its antibacterial activity. The results suggest that the developed film has the potential to be used as food-packaging material.