Extraction Of Anthocyanins Research Articles

A pH-sensitive film based on chitosan/gelatin and anthocyanin from Zingiber striolatum Diels for monitoring fish freshness

As a new type of packaging method, the anthocyanin-based pH-sensitive indicator film has gained much attention owing to low cost, small size, and visually informative property. In this study, an intelligent film based on chitosan/gelatin (CG) matrix with Zingiber striolatum Diels (ZSD) anthocyanin for fish freshness monitoring was developed. The film properties, including thickness, moisture content, color, mechanical properties, UV–vis light barrier property, as well as pH and ammonia sensitivity, were evaluated. The CG-ZSD films exhibited a more compact structure when compared with the CG film. The CG-ZSD20 film showed the highest elongation at break (6.33 ± 0.62%) and lowest tensile strength (20.0 ± 0.58 MPa). FTIR spectra revealed the strong hydrogen bond interactions between ZSD and polymer matrix. Film incorporated with 15% anthocyanin extract has increased melting temperature at 118.9 °C, and a lower weight loss (13.8%) at melting temperature. In pH 1–14 buffer, the color of CG-ZSD films underwent a significant change from red to yellow-green. The CG-ZSD15 film was utilized for monitoring fish freshness and showed visible color changes from deep purple to brown. The total volatile basic nitrogen content and pH value changes of fish were closely related to the visual color changes in film. This demonstrated that the film was a highly pH-sensitive film for quantifying fish freshness in real-time.

Formulation and characterization of nanocapsules loaded with roselle anthocyanins extract and enhancement of anthocyanins bioaccessibility

Hibiscus sabdariffa L. (roselle) is a medicinal and edible plant which rich in anthocyanins with potent antioxidant properties. To enhance the stability of roselle anthocyanins, they were encapsulated in nanocapsules composed of carboxymethyl chitosan (CMC), chitosan hydrochloride (CHC), and β-lactoglobulin (β-Lg). In vitro simulated digestion assays evaluated the impact of various core-to-wall ratios and β-Lg concentrations on the bioaccessibility of seven anthocyanins. Nanocapsules with a core-to-wall ratio of 1:2 and β-Lg at 10 mg/mL exhibited the highest encapsulation efficiency (EE). Cyanidin-3-glucoside had the highest EE, while cyanidin-3-sambubioside showed the outstanding retention rate. Furthermore, simulated digestion experiments combined with molecular docking revealed that peonidin-3-glucoside and petunidin-3-glucoside likely interact with and bind to the outer β-Lg layer of the nanocapsules, increasing their release during in vitro digestion. This study demonstrates that encapsulating roselle anthocyanins in CMC, CHC, and β-Lg nanocapsules significantly enhances their bioaccessibility.

Production of novel bio-transfer films composed from polyvinyl alcohol/sodium caseinate enhanced with bonded anthocyanins from poinsettia for minced meat preservation in double sheet system

This research explored the creation of new bio-transfer films composed of Polyvinyl alcohol (PVA), sodium caseinate (SC), and purified anthocyanin extract from poinsettia leaves (PAE). The films underwent evaluation to assess their color, physical characteristics, surface texture, crystalline structure, mechanical strength, and thermal stability. Incorporating up to 0.8% of purified anthocyanin extract (PAE) into the film matrix resulted in an opaque red color (a* = 43.96) and increased the opacity to 3.42 A/mm. This addition also made the films less permeable to water vapor, with a permeability rating of 1.021 (× 10− 10 g.m− 1 s− 1 pa− 1). The film surfaces remained smooth and crack-free at lower concentrations, but became rougher when the PAE concentration reached 1.2%. Fourier transform infrared (FT-IR) analysis indicated physical interactions between the PAE extract and the Polyvinyl alcohol (PVA)/sodium caseinate (SC) matrix. These films demonstrated strong thermal stability. Furthermore, the inclusion of PAE effectively stabilized the pH, total volatile basic nitrogen (TVB-N), and peroxide value (PV) of minced meat during cold storage compared with polypropylene (PP) and un covered samples (UC), showcasing its potential as an exceptional bio-transfer medium for anthocyanins. It was recommended that the utilization of anthocyanin-based bio-transfer films not only reduce minced meat loss during storage but also promotes sustainability efforts in food preservation.

Enhancing anthocyanin extraction efficiency in vegetables and fruits: a high-speed shear homogenization technology.

To extract anthocyanins with high efficiency, a hypothesis for high-speed shear homogenization extraction (HSHE) method was established through a combination of solvent and ultrasonic-assisted extractions. The efficacy of this hypothesis was demonstrated by performing qualitative and quantitative analyses of 16 anthocyanins extracted from five northern vegetables, and five berry fruits using ultra-high-performance Q-Exactive Orbitrap tandem mass spectrometry. Single-factor experiments were conducted by varying ethanol concentration, temperature, pH and extraction cycles to determine the optimal conditions for this method. Optimal extraction conditions (ethanol 70-80%, 40-50 °C, pH 3-4, performed twice) were determined using an HSHE (5 min, 10 000 rpm, 25 °C) assisted shaker (60 min) and ultrasonication (40 kHz, 160 W cm-2, 30 min, 25 °C) procedure. Compared to the traditional non-HSHE method, the total anthocyanin content obtained through HSHE extraction showed a significant increase, ranging from 1.0 to 3.9 times higher, with purple cabbage exhibiting the most pronounced enhancement in content. More types of anthocyanins were detected in blueberry (9), black bean (7) and raspberry (5), of which malvidin was the major anthocyanin (0.426 g kg-1) in blueberry, having an amount five times than previously obtained. The established HSHE method has been proven to be a superior technique for anthocyanin extraction, with higher extraction efficiency and concentrations. This technique also provides a new avenue for extracting bioactive compounds from diverse food sources, with potential applications in improving the functional properties of food products. © 2024 Society of Chemical Industry.

Anthocyanin‐Enhanced Bacterial Cellulose Nanofibers for Sustainable Hg(II) Ion Sensing

AbstractHg(II), poses a significant threat to both the environment and overall well‐being. The present indicator utilizes anthocyanin extract from roselle (Hibiscus sabdariffa), RSE, and incorporates it into bacterial cellulose nanofibers (BCNF) to detect Hg(II) ions. Through examination of the CIE Lab color variables, it is determined that the binding of Hg(II) leads to a discernible alteration in the color. The visible color changes as the Hg(II) concentration increases. ATR‐FTIR(Attenuated Total Reflectance‐Fourier transform infrared spectroscopy) and SEM(scanning electron microscopy) are utilized to analyze the bacterial cellulose nanofibers containing anthocyanin. The selectivity of the proposed sensor is assessed by conducting experiments with different types of metal ions including Co2+, Al3+, Na+, Ba2+, Ni2+, Mg2+, Cd2+, Pb2+, Fe2+, Fe3+, and Cu2+. The outcomes indicate that the sensor exhibits a remarkable ability to distinguish and respond specifically to Hg(II) ions. This particular sensing technique allows for the precise and reliable detection of Hg(II), with a detection limit of 0.72 ppm, by simply observing with the naked eye. For the effective treatment of a tap water sample, the BCNF‐RSE film provides successful results in the detection of Hg(II) ions. This innovative metallochromic sensor offers a promising solution for the on‐site, cost‐effective, portable, easy to use, and real‐time detection of Hg(II) ions.

Modern methods for obtaining purified anthocyanin extracts

Modern methods for obtaining purified anthocyanin extracts

Biopolymeric sensor based on natural deep eutectic solvents for monitoring meat spoilage

Ensuring food safety by monitoring freshness is crucial, particularly for high-protein meat products susceptible to spoilage. Smart packaging with pH-sensitive indicators, using natural pigments such as anthocyanin, provides a cost-effective and non-invasive solution. In this work, a novel colorimetric pH sensor based on biopolymer and natural deep eutectic solvents (NADES) is proposed. The NADES composed by Betaine: Glycerol: Water (BGH) was used for the anthocyanin extraction from Brassica oleracea (Purple Cabbage, PC), using the ultrasonic “one-step” method and BGH extraction efficiency was compared with water. Then, the BGH extract was mixed with different concentrations of xanthan gum (XG) 5, 10, 15 and 20%. The biopolymeric materials were characterized in terms of structure, mechanical properties, stability and pH response. The combination containing 10 % of xanthan gum (PC-BGH-XG10) presented suitable features to be used as a sensor. Thus, PC-BGH-XG10 was applied for real-time monitoring of meat spoilage. Interestingly colour changes were visible to the naked eye and they were successfully correlated with microbiological assays. To the best of our knowledge, this is the first integration of NADES and xanthan gum in the development of a colorimetric pH sensor. The proposed approach represents a green strategy for in-situ control of packaged foods intended for final consumption.

Enhancing the stability of anthocyanins extracts through adsorption into nanoclays – development of a smart biohybrid sensor for intelligent food packaging or as natural food additive/preservative

Anthocyanins (ACNs) are bioactive compounds sensible to high temperature, light and highly reactive to pH changes. These natural pigments present different colors according to the environment pH, which enables its use as bio-based sensor to control microbial quality of fresh perishable foodstuff. In this work, a biohybrid material (BH) composed of anthocyanins extract from jambolan fruit (Syzygium cumini) stabilized by adsorption onto montmorillonite (Mt) was developed, characterized and tested to monitor freshness of shrimp. Anthocyanins were recovered from extract using Mt as adsorbent at pH 1.5, 2.5, and 3.5 and temperatures of 10 and 20 °C. Langmuir and pseudo-second-order kinetic models were adjusted to explain these adsorption mechanisms. ACNs’ adsorption increased with decreasing pH (p > 0.05) and increasing temperature. At 20 °C and pH 1.5, 93 % of ACNs were recovered from extract (adsorption of 212.04 mg of ACNs/g of Mt). The obtained BH presented good stability and color changing capacity when exposed to ammonia vapor at pH varying from 1 to 13. Freshness of shrimp was monitored with the BH, validating its potential to be used as ammonia sensing or pH indicators in intelligent packaging.

Green Synthesis of Silver Nanoparticles from Anthocyanin Extracts of Peruvian Purple Potato INIA 328-Kulli papa.

In this work, AgNPs were synthesized using an anthocyanin extract from Peruvian purple potato INIA 328-Kulli papa. The anthocyanin extract was obtained through a conventional extraction with acidified ethanolic aqueous solvent. This extract acted as both a reducing and stabilizing agent for the reduction of silver ions. Optimization of synthesis parameters, including pH, reaction time, and silver nitrate (AgNO3) concentration, led to the optimal formation of AgNPs at pH 10, with a reaction time of 30 min and an AgNO3 concentration of 5 mM. Characterization techniques such as X-ray diffraction (XRD) and dynamic light scattering (DLS) revealed that the AgNPs had a crystallite size of 9.42 nm and a hydrodynamic diameter of 21.6 nm, with a zeta potential of -42.03 mV, indicating favorable colloidal stability. Fourier Transform Infrared (FTIR) analysis confirmed the presence of anthocyanin functional groups on the surface of the AgNPs, contributing to their stability. Furthermore, the bacterial activity of the AgNPs was evaluated by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). For E. coli, the MIC was 0.5 mM (0.05 mg/mL) and the MBC was 4.5 mM (0.49 mg/mL). Similarly, for S. aureus, the MIC was 0.5 mM (0.05 mg/mL) and the MBC was 4.0 mM (0.43 mg/mL). These results highlight the potential benefits of AgNPs synthesized from Peruvian purple potato anthocyanin extract, both in biomedical and environmental contexts.

Protective effect of Cyanidin-3-O-glucoside from blueberry anthocyanin extracts against hyperglycemia-induced outer BRB damage by suppressing REDD1-mediated VEGFA upregulation

Diabetic retinopathy (DR), caused by hyperglycemia, has been becoming the tremendous public health threaten globally. Recently, there has been a growing interest in using natural bioactive products for dietary intervention to manage the progression of DR. In this study, we utilized the streptozotocin (STZ)-induced retinopathy model in C57BL/6 J mice to investigate the impact of blueberry anthocyanin extract (BAEs) on the retinal cells of diabetic mice and assess the antioxidant activity of BAEs. Our results indicate that BAEs intervention significantly improved oxidative stress and inflammation levels in the retina of STZ-induced diabetic mice by downregulating the expression of regulated in development and DNA damage 1 (REDD1) in the choroid-retinal pigment epithelium (choroid-RPE). Cyanidin-3-O-glucoside (C3G), a primary component of BAEs, was further examined to explore potential molecular mechanisms. Our findings suggest that upregulation of REDD1 led to increase the vascular endothelial growth factor A (VEGFA) expression in ARPE-19 cells exposed to high glucose (HG); however, intervention with C3G mediated REDD1-driven VEGFA transcription and mitigated HG-induced changes in cell injury by regulating intracellular redox balance. The knockout of REDD1 effectively reversed HG-induced alterations in VEGFA levels, confirming the crucial role of REDD1 in the regulating of retinal vascular permeability factors. Overall, BAEs demonstrate potential in alleviating HG-induced DR, with the key component C3G exerting significant effects by inhibiting REDD1 activity and its downstream signaling pathways. These findings underscore the potential of REDD1 as a target for mitigating hyperglycemia-induced retinopathy and emphasize the value of BAEs as a dietary intervention strategy.

Anthocyanin Extract From Purple Sweet Potato Improving Neurotransmitter and Locomotor in Chronic Stressed-mice

Background: Prolonged stress plays an essential role in depression disorder through brain inflammation and neurotransmitter imbalances. The natural plant antioxidant is promising to resist the negative impact of stress. Objectives: This study aimed to analyze the effect of total anthocyanin (ANC) extracts from purple sweet potatoes (PSP) on brain neurotransmitters, inflammation, and locomotor behavior in the chronic-stressed mice model. Methods: Twenty male adult BALB/c mice were assigned to control, stress (STR), STR+ANC (10 mg/kg body weight [BW]), STR+ANC (20 mg/kg BW), and STR+ANC (40 mg/kg BW). Restraint stress was applied 2 h/d for 14 days. The enzyme-linked immunosorbent assay (ELISA) was performed to measure brain dopamine, gamma-aminobutyric acid (GABA), and corticosterone levels. The locomotor behavior was analyzed using an open field test before and after ANC treatment. In silico, molecular docking was carried out between ANC and monoamine oxidase-B (MAO-B) enzyme. Results: Administration of ANC decreased brain corticosterone levels. The dopamine neurotransmitter decreased in the stress-induced group and increased following ANC treatment. Increased GABA levels were observed in the stressed and treated groups. Locomotor analysis showed reduced total distance movement and velocity after ANC treatment. Molecular prediction showed that ANC can inhibit the MAO-B enzymes. Conclusion: The ANC extracted from PSP relieved brain inflammation and modified the neurotransmitters of dopamine and GABA, affecting the locomotor function of chronically stressed-induced mice. Furthermore, in vivo studies are necessary to evaluate the molecular mechanism of ANC from PSP in chronic stress exposure, particularly on MAO enzyme regulation.

The making instant rice from various types of rice with the addition of natural anthocyanin extract

Abstract This research aimed to determine the effect of the type of rice and the source of anthocyanin extract on the physical, chemical and organoleptic properties of the instant rice produced, to obtain instant rice with high antioxidant activity but which is still preferred by consumers. Anthocyanin extracts from butterfly pea flowers (B1), mangosteen peel (B2) and dragon fruit peel (B3) were made from 10 g of powder which was macerated in 100 ml of boiled distilled water for 15 minutes. Rice from varieties IR-64 (A1), rojolele (A2) and ciherang (A3) that have been sorted, 100 g each, washed clean and drained, then each added with anthocyanin extract B1, B2 and B3 in a ratio of 1 :1 (w/v), then mixed. Each rice to which anthocyanin extract has been added is then cooked using a rice cooker for 15 minutes, then removed and air-dried for 5 minutes, then followed by drying using an oven at 60°C for 24 hours until dry instant rice is obtained. The results of the study showed that the type of rice had an effect on the color preference of instant rice, but had no effect on antioxidant activity, water content, reducing sugar content, rehydration time, aroma preference, texture preference and taste preference. The source of anthocyanin extract affected on the antioxidant activity and color preference of instant rice, but has no effect on the water content, rehydration time, aroma preference, texture preference and taste preference. The instant rice made from IR 64 which added butterfly pea flowers anthocyanin extract is recommended because it contains the highest antioxidants with antioxidant activity of 76.48%, water content of 7.18%, rehydration time of 10.18 minutes, reducing sugar content of 0.37% and an average favorability value of 4.66 (somewhat like).

Extraction of anthocyanin from mangosteen rind using ionic liquids and deep eutectic solvents

Abstract Anthocyanins is natural pigments found in many plants that not only impart colours but also have potential health benefits and used as natural colorant in food processing industries. Mangosteen rind, although rich in anthocyanins, is normally disposed of as waste after consuming the delicate pulp. Anthocyanins is stored within the membrane cell wall inside the mangosteen rind, and it is usually recovered from the rind using solvent. Hence, this study investigated potential alternative green solvents, e.g., ionic liquids and deep eutectic solvents in extracting anthocyanins from mangosteen rind. This study is designed in conjunction with Sustainable Development Goals (SDGs) outlined by the United Nations, particularly SDG3 where good health and well-being equalities are emphasized and SDG12 in which efficient management of natural resource is addressed. Anthocyanins yield was determined using pH-differential method and result was expressed in milligram of cyanidin-3-glucoside per gram of mangosteen rind (mg cy-3-glu/g). Results showed that mangosteen rind extracted using both ionic liquids e.g., 1-ethy-3metylimidazolium bromide (EMIM) and 1-butyl-3methylimidazolium bromide (BMIM) solutions gave higher anthocyanins yields of 0.72 mg cy-3-glu/g and 0.69 mg cy-3-glu/g, respectively, in comparison to the 50% ethanol and deep eutectic solvents. This study revealed that high viscosity of deep eutectic solvent was the main factor that hindered the penetration of the solvent into the cell membrane of mangosteen rind, as a result, lower anthocyanins yields were obtained. Hence, in bioactive compounds extraction from plant materials, deep eutectic solvent incorporated with ultrasound or microwave is recommended as it could enhance the penetration of solvent into the plant’s matrix.

Utilization of Organic Waste as A Natural Detector of Formaldehyde on-Campus Snacks

The aim of this research is to reduce household organic waste through the use of organic waste as a natural detector of formaldehyde content in food snacks. The organic waste used in this study was red garlic skins, dragon fruit skins and purple sweet potato skins. This research is an experimental research. The stages of the research started with the extraction of anthocyanins from the three organic wastes, direct detection of formalin and detection of food ingredients. The formalin concentrations tested were 0.5%, 1%, 2%, 5% and 25%. Detection ability can be seen from the color change between control and formalin treatment. Garlic skin produces a red extract, dragon fruit skin produces an orange extract, and purple sweet potato skin produces a deep red extract. Test results on 20 samples of food snacks around the campus using the three organic waste extracts proved that all samples contained formaldehyde in varying concentrations. The highest 50% formalin content was found in yellow noodles and meatballs. The conclusion is that purple beetle skin, dragonfruit skin, and red garlic skin can be used as natural detectors for formalin in campus snacks.

Valorization of Hibiscus Flower (Hibiscus sabdariffa L.) Anthocyanins to Produce Sustainable Spray-Dried Ingredients

The recent increase in sustainability awareness has triggered the industry to establish novel, eco-friendly sources of plant-based ingredients. In the present study, hibiscus flowers (Hibiscus sabdariffa L.) were investigated as a sustainable source of anthocyanins for use in spray-dried ingredients with antioxidant capacity. To this end, the extraction and spray-drying microencapsulation of hibiscus flower anthocyanins were optimized and the final products were evaluated for their oxidative stability index. Initially, preliminary experiments were carried out to evaluate the effects of selected processing parameters on anthocyanin extraction. Next, the extraction was optimized through a 22 central composite design, considering ethanol concentration (44–56% v/v) and extraction time (1.6–6.4 h) as independent factors. The optimum extraction conditions (8 h, 41.6% v/v ethanol concentration) were used to produce anthocyanin-rich extracts, which were microencapsulated by spray drying using a 22 central composite design with the carrier addition rate (1–3% w/v) and inlet temperature (160–192 °C) as factors. Maximum values of solids recovery (60.8%) and anthocyanin retention (96.0%) were reached when 3.2% w/v of starch–alginate carrier blend and a 170.7 °C inlet temperature were used. Finally, when hibiscus microcapsules were added to soybean oil, higher oxidative stability was achieved compared to the control. Overall, we demonstrate an industrially friendly and scalable approach that takes advantage of abundant hibiscus flowers as a viable source of anthocyanins for multiple applications.

Petunidin-3-O-[rhamnopyranosyl-(trans-p-coumaroyl)]-5-O-(β-D-glucopyranoside), the main anthocyanin from the fruits of Lycium ruthenicum murray, enhances the lifespan of Caenorhabditis elegans by activating DAF-16 and improving the gut microbiota

Research on anti-aging activity primarily focuses on crude extracts of anthocyanins, while relatively less attention has been given to anthocyanin monomers. This study was focused on exploring the anti-aging properties of the main anthocyanin monomer, petunidin-3-O-[rhamnopyranosyl-(trans-p-coumaroyl)]-5-O-(β-D-glucopyranoside) (P3G), from the fruits of Lycium ruthenicum Murray. The effects of P3G on stress endurance, lifespan, and gut microbiota in Caenorhabditis elegans were investigated. It was found that P3G significantly extended the mean lifespan by 19.50%, enhanced fitness through increased motility (30.39%) and pharyngeal pumping (18.33%), and reduced lipofuscin accumulation by 43.61% while maintaining fecundity. P3G prolonged lifespan by 20.13% and 18.82% during oxidative and heat stress, correspondingly. This effect was attributed to the activation of stress-related genes and the antioxidant system. The transcriptome results showed the enrichment in the longevity pathway and biosynthesis pathway of nematodes. The prominent role of the DAF-16 pathway was highlighted, as P3G enhanced the expression of daf-16 gene and downstream genes (sod-2, sod-3, and mlt-1), promoting nuclear accumulation of DAF-16. Moreover, modifications in the gut microbiota induced by P3G played a role in its anti-aging properties by governing gut microbial composition. Overall, P3G appeared to contribute to promoting the health of nematodes and might help delay their aging to some extent.

Effect of Antigonon leptopus extract in corn starch-glycerol based film as colourimetric indicator film for monitoring fish freshness

A colourimetric indicator can be used to test the freshness of fish in a rapid, straightforward and non-destructive manner. Anthocyanin, a natural dye found in Antigonon leptopus flowers, has a sensitive colour reactivity to a wide range of pH levels and can be made into colourimetric indicator films on a laboratory scale, making it a viable replacement for artificial dyes. The study's purpose was to see how the concentration of A. leptopus extract affected the colourimetric assessment of fish freshness. Ethanol was used to extract anthocyanin from A. leptopus. FTIR and pHrespond spectroscopies were used to characterise the extracts. Colourimetric indicator films were developed to assess fish freshness by incorporating A. leptopus extract into a corn starch-glycerol matrix via the solution casting method, with concentrations of 10%, 30% and 50%, respectively. The effect of A. leptopus extract on visual aspects, thickness, morphology, FTIR spectra, UV-Vis spectra and colour responses was analysed. Microbial analysis, TVB-N contents, firmness, and pH of the fish samples were analysed after storage. The colour of the original films became darker as the extracted content increased. There was no significant (p>0.05) effect of A. leptopus extract on film thickness. SEM micrographs revealed that the composite films had homogeneous and whitish granules on the surface and that increasing the A. leptopus extract concentration caused the films to become rougher. FTIR and UV-Vis spectroscopies showed successful binding between A. leptopus extracts and corn starch-glycerol film. With increasing pH, the colour change of the films exposed to pH = 3-11 solutions was no significant difference due to improper storage. An increase in the microbial population, TVB-N content and pH was observed over the storage period as a result of fish deterioration. Colour changes were also identified in the film which became darker. Overall, colourimetric indicator film with 50% A. leptopus extract was found to be the optimal formulation since it had the highest values in ∆E* during progressive spoilage of fish.

Research Progress on the Extraction and Purification of Anthocyanins and Their Interactions with Proteins.

Anthocyanins, as the most critical water-soluble pigments in nature, are widely present in roots, stems, leaves, flowers, fruits, and fruit peels. Many studies have indicated that anthocyanins exhibit various biological activities including antioxidant, anti-inflammatory, anti-tumor, hypoglycemic, vision protection, and anti-aging. Hence, anthocyanins are widely used in food, medicine, and cosmetics. The green and efficient extraction and purification of anthocyanins are an important prerequisite for their further development and utilization. However, the poor stability and low bioavailability of anthocyanins limit their application. Protein, one of the three essential nutrients for the human body, has good biocompatibility and biodegradability. Proteins are commonly used in food processing, but their functional properties need to be improved. Notably, anthocyanins can interact with proteins through covalent and non-covalent means during food processing, which can effectively improve the stability of anthocyanins and enhance their bioavailability. Moreover, the interactions between proteins and anthocyanins can also improve the functional characteristics and enhance the nutritional quality of proteins. Hence, this article systematically reviews the extraction and purification methods for anthocyanins. Moreover, this review also systematically summarizes the effect of the interactions between anthocyanins and proteins on the bioavailability of anthocyanins and their impact on protein properties. Furthermore, we also introduce the application of the interaction between anthocyanins and proteins. The findings can provide a theoretical reference for the application of anthocyanins and proteins in food deep processing.

Gelatin/polyvinyl alcohol films incorporated with different blueberry extracts as potential colorimetric indicators to detect acidic and basic vapors

Blueberry extract is rich in phenolic compounds and anthocyanins, which can undergo color changes when subjected to different pH conditions. This feature makes it liable to be incorporated into polymeric matrices to form colorimetric indicator films. In this sense, films based on gelatin and polyvinyl alcohol (PVA) were elaborated with raw blueberry extracts (EB), purified fractions of phenolic extract (EF), or anthocyanin extract (EFA). Their color sensitivity to acidic and basic vapors was investigated. Higher levels of phenolic compounds and total anthocyanins were observed for EB and EFA. The EFA was more sensitive to acidic and basic vapors, with an intense visual colorimetric change attributed to the anthocyanins. The higher absorbance in the 400 nm wavelength region observed in both EF and EB spectra was possibly due to the presence of yellow phenolic compounds. Corroborating to the findings for the extract, the EFA film presented a tone shift over time and a higher overall color difference, completely changing from a greenish color to purple under acidic vapors. However, the EB film has shown to be more susceptible to basic conditions, exhibiting differences in h° values over time under basic vapors. Therefore, PVA/gelatin films incorporated with EB are recommended for the colorimetric indication of nitrogenous bases, and the EFA-added films for volatile acids. Based on the results, films incorporated with EB or EFA can be used to monitor, detect, and report the presence of acidic and basic volatiles from food deterioration.

Comparison of different drying pretreatment combined with ultrasonic-assisted enzymolysis extraction of anthocyanins from Lycium ruthenicum Murr.

Extraction of anthocyanins from Lycium ruthenicum Murr. (L. ruthenicum) is a notable challenge in food production, requiring methods that balance efficiency and safety. In this study, we conducted a comparative analysis the extraction of anthocyanins by natural air drying (NAD), vacuum freeze drying (VFD), hot air drying (HAD), and vacuum microwave drying (MVD) combined with ultrasonic-assisted enzymolysis extraction (UAEE). The results demonstrated that the extraction yield and antioxidant activity of anthocyanins were significantly higher in VFD. This phenomenon can be attributed to the modification of raw material’s microstructure, leading to an increased extraction yield of specific anthocyanins such as Cyanidin-3-galactoside, Delphinidin chloride, Cyanidin, and Petunidin. According to the pretreatment results, the extraction process of anthocyanins was further optimized. The highest yield (3.16 g/100 g) was obtained in following conditions: 0.24 % pectinase, 48 °C, solid:liquid = 1:21, and 21 min ultrasonic time. This study improves the commercial value and potential application of L. ruthenicum in food industry.