Food colorants: Challenges, opportunities and current desires of agro-industries to ensure consumer expectations and regulatory practices

Removal of food dyes using biological materials via adsorption: A review

It is alarming that synthetic food dyes (FD) are widely used in various industries and that these facilities discharge their wastewater into the environment without treating it. FDs mixed into industrial wastewater pose a threat to the environment and human health. Therefore, removing FDs from wastewater is very important. This review explores the burgeoning field of FD removal from wastewater through adsorption using biological materials (BMs). By synthesizing a wealth of research findings, this comprehensive review elucidates the diverse array of BMs employed, ranging from algae and fungi to agricultural residues and microbial biomass. Furthermore, this review investigates challenges in practical applications, such as process optimization and scalability, offering insights into bridging the gap between laboratory successes and real-world implementations. Harnessing the remarkable adsorptive potential of BMs, this review presents a roadmap toward transformative solutions for FD removal, promising cleaner and safer production practices in the food and beverage industry.

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.

Recent advances in engineering microorganisms for the production of natural food colorants

Food colorants are frequently added to processed foods since color is an important tool in the marketing of food products, influencing consumer perceptions, preferences, and purchasing behavior. While synthetic dyes currently dominate the food colorant market, consumer concern regarding their safety and sustainability is driving a demand for their replacement with naturally derived alternatives. However, natural colorants are costly compared to their synthetic counterparts as the pigment content in the native sources is usually very low and extraction can be challenging. Recent advances in the engineering of microbial metabolism have sparked interest in the development of cell factories capable of producing natural colorants from renewable resources. This review summarizes major developments within metabolic engineering for the production of nature-identical food colorants by fermentation. Additionally, it highlights common applications, formulations, and physicochemical characteristics of prevalent pigment classes. Lastly, it outlines a workflow for accelerating the optimization of cell factories for the production or derivatization of nature-identical food colorants.

Pruned tea biomass plays a significant role in functional food production: A review on characterization and comprehensive utilization of abandon-plucked fresh tea leaves

Tea is the second largest nonalcoholic beverage in the world due to its characteristic flavor and well-known functional properties in vitro and in vivo. Global tea production reaches 6.397 million tons in 2022 and continues to rise. Fresh tea leaves are mainly harvested in spring, whereas thousands of tons are discarded in summer and autumn. Herein, pruned tea biomass refers to abandon-plucked leaves being pruned in the non-plucking period, especially in summer and autumn. At present, no relevant concluding remarks have been made on this undervalued biomass. This review summarizes the seasonal differences of intrinsic metabolites and pays special attention to the most critical bioactive and flavor compounds, including polyphenols, theanine, and caffeine. Additionally, meaningful and profound methods to transform abandon-plucked fresh tea leaves into high-value products are reviewed. In summer and autumn, tea plants accumulate much more phenols than in spring, especially epigallocatechin gallate (galloyl catechin), anthocyanins (catechin derivatives), and proanthocyanidins (polymerized catechins). Vigorous carbon metabolism induced by high light intensity and temperature in summer and autumn also accumulates carbohydrates, such as soluble sugars and cellulose. The characteristics of abandon-plucked tea leaves make them not ideal raw materials for tea, but suitable for novel tea products like beverages and food ingredients using traditional or hybrid technologies such as enzymatic transformation, microbial fermentation, formula screening, and extraction, with the abundant polyphenols in summer and autumn tea serving as prominent flavor and bioactive contributors.

Portable electrochemical sensing platform based on amidated GO-MOF and PEDOT:PSS for high-efficient detection of ponceau 4R

A promising electrochemical sensing platform for the detection of ponceau 4R in food has been fabricated based on the carboxylated graphene oxide (GO-COOH), metal-organic framework (MOF) UIO-66-NH2, and poly (3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS). To this end GO-COOH was covalently coupled with UIO-66-NH2 through amide reaction, endowing the material (GO-CONH-UIO-66) unique hierarchical pores and high chemical stability and as a result improving the conductivity of MOF and the dispersion of GO. After the addition of PEDOT:PSS into GO-CONH-UIO-66, the continuity and conductivity of the composite (PEDOT:PSS/GO-CONH-UIO-66) have been further enhanced, due to the high conductivity, favorable film-forming, and hydrophilic properties of PEDOT:PSS. Systematic electrochemical experiments confirm that the PEDOT:PSS/GO-CONH-UIO-66/GCE shows satisfactory electrochemical sensing properties towards the detection of ponceau 4R, with a wide linear detection range of 0.01-30 μM, a low limit of detection of 3.33 nM, and a high sensitivity of 0.606 μA μM-1 cm-2. The PEDOT:PSS/GO-CONH-UIO-66 sensing platform was successfully used to detect ponceau 4R in beverage, and the detection results were compared with  high-performance liquid chromatography. As a result, the PEDOT:PSS/GO-CONH-UIO-66 composite shows a promising application prospect for rapid detection of ponceau 4R in food and will play significant role in food safety detection and supervision.

Are health claims in aging-related functional food packages different from those of general functional foods? Content analysis of food packaging from Taiwan

Given the challenges of aging populations, both in Taiwan and globally, issues related to older consumers need more attention. According to surveys in Taiwan, food is one of the most important consumer products for older adults. In recent years, functional foods have become popular, often using health claims as a promotional tool. Therefore, this study has investigated food product packaging in common retail channels in Taiwan by conducting a content analysis of all items with health claims (160 samples). This study specifically compared products related to aging and those unrelated to aging. The results revealed that more than half the participants with health claims did not provide specific descriptions of their health effects. Furthermore, products related to aging often included health terms and claims to supplement with specific nutrients in their health claims. This study has aimed to offer recommendations for educating older consumers, regulating health claims in food advertising, promoting an age-friendly consumer environment, and consumer protection.

Lignocellulosic materials valorization in second generation biorefineries: an opportunity to produce fungal biopigments

Second generation biorefineries play an important role in the production of renewable energy and fuels, utilizing forest and agro-industrial residues and by-products as raw materials. The integration of novel bioproducts, such as: xylitol, β-carotene, xylooligosaccharides, and biopigments into the biorefinery's portfolio can offer economic benefits in the valorization of lignocellulosic materials, particularly cellulosic and hemicellulosic fractions. Fungal biopigments, known for their additional antioxidant and antimicrobial properties, are appealing to consumers and can have applications in various industrial sectors, including food and pharmaceuticals. The use of lignocellulosic materials as carbon and nutrient sources for the growth medium helps to reduce production costs, increasing the competitiveness of fungal biopigments in the market. In addition, the implementation of biopigment production in biorefineries allows the utilization of underutilized fractions, such as hemicellulose, for value-added bioproducts. This study deals with the potential of fungal biopigments production in second generation biorefineries in order to diversify the produced biomolecules together with energy generation. A comprehensive and critical review of the recent literature on this topic has been conducted, covering the major possible raw materials, general aspects of second generation biorefineries, the fungal biopigments and their potential for incorporation into biorefineries.

Synthetic Colors in Food: A Warning for Children's Health

This study addressed the harmful effects of artificial colors in pediatric populations, including children diagnosed with Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD), as well as those without behavioral disorders. There is a consensus that synthetic food colorings have several impacts on consumers, especially pediatrics, due to their influence on sensory appeal, which can encourage preference for certain foods. The results revealed that these color additives are directly linked to a series of health problems, with a greater impact on children, including a predisposition to pathological conditions such as carcinogenic, allergenic, mutagenic, cytotoxic, and clastogenic activities, as well as gastrointestinal and respiratory problems, in addition to behavioral changes in children with and without diagnosed disorders. The harms of synthetic dyes in children with or without comorbidities are worrying and require a careful and proactive approach from parents, caregivers and public authorities.

Sunset Yellow dye effects on gut microbiota, intestinal integrity, and the induction of inflammasomopathy with pyroptotic signaling in male Wistar rats

Although concern persists regarding possible adverse effects of consumption of synthetic azo food dyes, the mechanisms of any such effects remain unclear. We have tested the hypothesis that chronic consumption of the food dye Sunset Yellow (SY) perturbs the composition of the gut microbiota and alters gut integrity. Male rats were administered SY orally for 12 weeks. Analysis of fecal samples before and after dye administration demonstrated SY-induced microbiome dysbiosis. SY treatment reduced the abundance of beneficial taxa such as Treponema 2, Anaerobiospirillum, Helicobacter, Rikenellaceae RC9 gut group, and Prevotellaceae UCG-003, while increasing the abundance of the potentially pathogenic microorganisms Prevotella 2 and Oribacterium. Dysbiosis disrupted gut integrity, altering the jejunal adherens junction complex E-cadherin/β-catenin and decreasing Trefoil Factor (TFF)-3. SY administration elevated LPS serum levels, activated the inflammatory inflammasome cascade TLR4/NLRP3/ASC/cleaved-activated caspase-1 to mature IL-1β and IL-18, and activated caspase-11 and gasdermin-N, indicating pyroptosis and increased intestinal permeability. The possibility that consumption of SY by humans could have effects similar to those that we have observed in rats should be examined.

A review on mechanisms and impacts of cold plasma treatment as a non-thermal technology on food pigments

Food characteristics like appearance and color, which are delicate parameters during food processing, are important determinants of product acceptance because of the growing trend toward more diverse and healthier diets worldwide, as well as the increase in population and its effects on food consumption. Cold plasma (CP), as a novel technology, has marked a new trend in agriculture and food processing due to the various advantages of meeting both the physicochemical and nutritional characteristics of food products with minimal changes in physical, chemical, nutritional, and sensorial properties. CP processing has a positive impact on food quality, including the preservation of natural food pigments. This article describes the influence of CP on natural food pigments and color changes in vegetables and fruits. Attributes of natural pigments, such as carotenoids, chlorophyll, anthocyanin, betalain, and myoglobin, are presented. In addition, the characteristics and mechanisms of CP processes were studied, and the effect of CP on mentioned pigments was investigated in recent literature, showing that the use of CP technology led to better preservation of pigments, improving their preservation and extraction yield. While certain modest and undesirable changes in color are documented, overall, the exposure of most food items to CP resulted in minor loss and even beneficial influence on color. More study is needed since not all elements of CP treatment are currently understood. The negative and positive effects of CP on natural food pigments in various products are discussed in this review.

Gardenia yellow pigment: Extraction methods, biological activities, current trends, and future prospects

Food coloring plays a vital role in influencing consumers' food choices, imparting vibrant and appealing colors to various food and beverage products. Synthetic food colorants have been the most commonly used coloring agents in the food industry. However, concerns about potential health issues related to synthetic colorants, coupled with increasing consumer demands for food safety and health, have led food manufacturers to explore natural alternatives. Natural pigments not only offer a wide range of colors to food products but also exhibit beneficial bioactive properties. Gardenia yellow pigment is a water-soluble natural pigment with various biological activities, widely present in gardenia fruits. Therefore, this paper aims to delve into Gardenia Yellow Pigment, highlighting its significance as a food colorant. Firstly, a thorough understanding and exploration of various methods for obtaining gardenia yellow pigment. Subsequently, the potential functionality of gardenia yellow pigment was elaborated, especially its excellent antioxidant and neuroprotective properties. Finally, the widespread application trend of gardenia yellow pigment in the food industry was explored, as well as the challenges faced by the future development of gardenia yellow pigment in the field of food and health. Some feasible solutions were proposed, providing valuable references and insights for researchers, food industry professionals, and policy makers.

Intelligent and active biodegradable biopolymeric films containing carotenoids

There is growing interest in the use of natural bioactive compounds for the development of new bio-based materials for intelligent and active food packaging applications. Several beneficial effects have been associated with the antioxidant and antimicrobial potentials of carotenoid compounds. In addition, carotenoids are sensitive to pH changes and oxidation reactions, which make them useful bioindicators of food deterioration. This review summarizes the current research on the application of carotenoids as novel intelligent and active biodegradable food packaging materials. Carotenoids recovered from food processing by-products can be used in the development of active food packaging materials due to their antioxidant properties. They help maintain the stability of lipid-rich foods, such as vegetable oils. Additionally, when incorporated into films, carotenoids can monitor food oxidation, providing intelligent functionalities.

Studying the impact of phycoerythrin on antioxidant and antimicrobial activity of the fresh rainbow trout fillets

Marine cyanobacteria present a significant potential source of new bioactive compounds with vast structural diversity and relevant antimicrobial and antioxidant activities. Phycobiliproteins (PBPs) like phycocyanin (PC), phycoerythrin (PE), and water-soluble cyanobacterial photosynthetic pigments, have exhibited strong pharmacological activities and been used as natural food additives. In this study, phycoerythrin (PE) isolated from a marine strain of cyanobacterium Nostoc sp. Ft salt, was applied for the first time as a natural antimicrobial as well as an antioxidant to increase the shelf life of fresh rainbow trout i.e., (Oncorhynchus mykiss) fillets. Fresh trout fillets were marinated in analytical grade PE (3.9 μg/mL) prepared in citric acid (4 mg/mL), and stored at 4 °C and 8 °C for 21 days. Microbiological analysis, antioxidant activity and organoleptic evaluation of both control and treated fish fillets were then statistically compared. The results demonstrated noticeable (P < 0.05) differences in the microbial counts, antioxidant activity, and organoleptic characteristic values between PE-treated and non-treated groups. In addition, we observed that treating fresh fish fillets with a PE solution leads to a significant increase in shelf life by at least 14 days. Consequently, PE could be an alternative to synthetic chemical additives since it does not contain the potentially dangerous residues of the synthetic chemical additives and is thus healthier to the consumers.

Individual and Simultaneous Electrochemical Detection of Allura Red and Acid Blue 9 in Food Samples Using a Novel La2YCrO6 Double Perovskite Decorated on HLNTs as an Electrocatalyst

The present study involved the synthesis of La2YCrO6 double perovskites using a sol-gel approach. Additionally, a sonication method was implemented to prepare La2YCrO6 double perovskites decorated on halloysites (La2YCrO6/HLNTs). The La2YCrO6/HLNTs exhibited remarkable conductivity, electrocatalytic activity, and rapid electron transfer. It is imperative to possess these characteristics when overseeing the concurrent identification of Allura red (AR) and acid blue 9 (AB) in food samples. The development of the La2YCrO6/HLNTs was verified through the utilization of diverse approaches for structural and morphological characterization. The electrochemical techniques were employed to evaluate the analytical techniques of La2YCrO6/HLNTs. Impressively, the La2YCrO6/HLNTs demonstrated exceptional sensitivity, yielding the lowest detection limit for AR at 8.99 nM and AB at 5.14 nM. Additionally, the linear concentration range was 10-120 nM (AR and AB). The sensor that was developed exhibited remarkable selectivity, and the feasibility of AR and AB in the food sample was effectively monitored, resulting in satisfactory recoveries.

Modeling sunset yellow removal from fruit juice samples by a novel chitosan-nickel ferrite nano sorbent

Analysis of food additives is highly significant in the food industry and directly related to human health. This investigation into the removal efficiency of sunset yellow as an azo dye in fruit juices using Chitosan-nickel ferrite nanoparticles (Cs@NiFe2O4 NPs). The nanoparticles were synthesized and characterized using various techniques. The effective parameters for removing sunset yellow were optimized using the response surface methodology (RSM) based on the central composite design (CCD). Under the optimum conditions, the highest removal efficiency (94.90%) was obtained for the initial dye concentration of 26.48 mg L-1 at a pH of 3.87, a reaction time of 67.62 min, and a nanoparticle dose of 0.038 g L-1. The pseudo-second-order kinetic model had a better fit for experimental data (R2 = 0.98) than the other kinetic models. The equilibrium adsorption process followed the Freundlich isotherm model with a maximum adsorption capacity of 212.766 mg g-1. The dye removal efficiency achieved for industrial and traditional fruit juice samples (91.75% and 93.24%), respectively, confirmed the method's performance, feasibility, and efficiency. The dye adsorption efficiency showed no significant decrease after five recycling, indicating that the sorbent has suitable stability in practical applications. variousThe synthesized nanoparticles can be suggested as an efficient sorbent to remove the sunset yellow dye from food products.

Effect of red beet cooking water on yoghurt's physico-chemical, textural and antioxidant characteristics

This study aimed to evaluate the effect of red beet cooking (Beta vulgaris L.) water on the quality properties of yoghurts prepared with different levels (2, 4, 8, and 10% w/w) compared to the nature sample. Results showed a decrease in pH value and an increase in titratable acidity (TA), fat content, and dry matter with the increasing red beet cooking water concentration. Consumer test revealed that incorporating 4% (w/w) red beet cooking water into yoghurt influences the product's overall acceptability compared to the other formulations. The addition of red beet cooking water at the level of 4% induces significant increase in gel firmness with a decrease in syneresis compared to the control sample. The lightness and yellowing of the product decreased while the redness increased. Furthermore, the effect of red beet cooking water addition was significant (p < 0.05) on total phenolic contents (0.369 ± 0.024) as well as antioxidant activity (0.140 ± 0.008). Beet cooking water may be a potential ingredient in the formulation of functional products.

Microbial pigments: Sources, current status, future challenges in cosmetics and therapeutic applications

Color serves as the initial attraction and offers a pleasing aspect. While synthetic colorants have been popular for many years, their adverse environmental and health effects cannot be overlooked. This necessitates the search for natural colorants, especially microbial colorants, which have proven and more effective. Pigment-producing microorganisms offer substantial benefits. Natural colors improve product marketability and bestow additional benefits, including antioxidant, antiaging, anticancer, antiviral, antimicrobial, and antitumor properties. This review covers the various types of microbial pigments, the methods to enhance their production, and their cosmetic and therapeutic applications. We also address the challenges faced during the commercial production of microbial pigments and propose potential solutions.

Applications of Plant Bioactive Compounds as Replacers of Synthetic Additives in the Food Industry

According to the Codex Alimentarius, a food additive is any substance that is incorporated into a food solely for technological or organoleptic purposes during the production of that food. Food additives can be of synthetic or natural origin. Several scientific evidence (in vitro studies and epidemiological studies like the controversial Southampton study published in 2007) have pointed out that several synthetic additives may lead to health issues for consumers. In that sense, the actual consumer searches for "Clean Label" foods with ingredient lists clean of coded additives, which are rejected by the actual consumer, highlighting the need to distinguish synthetic and natural codded additives from the ingredient lists. However, this natural approach must focus on an integrated vision of the replacement of chemical substances from the food ingredients, food contact materials (packaging), and their application on the final product. Hence, natural plant alternatives are hereby presented, analyzing their potential success in replacing common synthetic emulsifiers, colorants, flavorings, inhibitors of quality-degrading enzymes, antimicrobials, and antioxidants. In addition, the need for a complete absence of chemical additive migration to the food is approached through the use of plant-origin bioactive compounds (e.g., plant essential oils) incorporated in active packaging.

Mechanism of Enhancing Chlorophyll Photostability through Light-Induced Chlorophyll/Phycocyanin Aggregation

Chlorophyll (Chl) is the most abundant pigment in photosynthetic plants, but it is prone to degradation during processing and storage, limiting its usage in the food industry. This study developed a technique for increasing Chl photostability by light-induced Chl/phycocyanin (PC) triple synergistic aggregation. Under continuous illumination settings, the results revealed that the Chl retention increased to 406% compared to the control. A model of Chl/PC complexes was constructed using multiligand molecular docking, and the aggregation mechanism was investigated by quantum chemistry, which demonstrated that PC could provide an ideal central hydrophobic cavity for Chl aggregates and thus further enhance the aggregation of Chl on the basis of Chl/PC complexes. The core driver of the improved photostability of Chl is photoexcitation-induced Chl aggregates. This study enriches our understanding of the interaction mechanism between PC and Chl, and we hope that this study can provide broader ideas for the development of natural pigment products.

Beet red food colourant can be produced more sustainably with engineered Yarrowia lipolytica

Synthetic food colourants are widely used in the food industry, but consumer concerns about safety and sustainability are driving a need for natural food-colour alternatives. Betanin, which is extracted from red beetroots, is a commonly used natural red food colour. However, the betanin content of beetroot is very low (~0.2% wet weight), which means that the extraction of betanin is incredibly wasteful in terms of land use, processing costs and vegetable waste. Here we developed a sustainability-driven biotechnological process for producing red beet betalains, namely, betanin and its isomer isobetanin, by engineering the oleaginous yeast Yarrowia lipolytica. Metabolic engineering and fermentation optimization enabled production of 1,271 ± 141 mg l-1 betanin and 55 ± 7 mg l-1 isobetanin in 51 h using glucose as carbon source in controlled fed-batch fermentations. According to a life cycle assessment, at industrial scale (550 t yr-1), our fermentation process would require significantly less land, energy and resources compared with the traditional extraction of betanin from beetroot crops. Finally, we apply techno-economic assessment to show that betanin production by fermentation could be economically feasible in the existing market conditions.

Comprehensive Update on Carotenoid Colorants from Plants and Microalgae: Challenges and Advances from Research Laboratories to Industry

The substitution of synthetic food dyes with natural colorants continues to be assiduously pursued. The current list of natural carotenoid colorants consists of plant-derived annatto (bixin and norbixin), paprika (capsanthin and capsorubin), saffron (crocin), tomato and gac fruit lycopene, marigold lutein, and red palm oil (α- and β-carotene), along with microalgal Dunaliella β-carotene and Haematococcus astaxanthin and fungal Blakeslea trispora β-carotene and lycopene. Potential microalgal sources are being sought, especially in relation to lutein, for which commercial plant sources are lacking. Research efforts, manifested in numerous reviews and research papers published in the last decade, have been directed to green extraction, microencapsulation/nanoencapsulation, and valorization of processing by-products. Extraction is shifting from conventional extraction with organic solvents to supercritical CO2 extraction and different types of assisted extraction. Initially intended for the stabilization of the highly degradable carotenoids, additional benefits of encapsulation have been demonstrated, especially the improvement of carotenoid solubility and bioavailability. Instead of searching for new higher plant sources, enormous effort has been directed to the utilization of by-products of the fruit and vegetable processing industry, with the application of biorefinery and circular economy concepts. Amidst enormous research activities, however, the gap between research and industrial implementation remains wide.

Exploring the Potential of Water-Soluble Squid Ink Melanin: Stability, Free Radical Scavenging, and Cd2+ Adsorption Abilities

Squid ink melanin can be efficiently extracted from the byproduct ink sac generated during squid processing. As a natural food colorant, it possesses inherent antioxidant properties and the capability to adsorb heavy metals. This study aims to investigate the solubility of water-soluble squid ink melanin (WSSM) obtained from the ink sac, as well as its stability under various conditions including temperature, pH, salt, sugar, potassium sorbate, metal ions, sodium benzoate, sodium sulfite (reducing agent), and hydrogen peroxide (oxidizing agent). Moreover, it explores the scavenging effects of WSSM on free radicals and cadmium ions. The findings suggest that WSSM's stability is insignificantly affected by high temperature, sucrose, and salt. However, acidity, sodium benzoate, potassium sorbate, sodium sulfite (Na2SO3), and hydrogen peroxide (H2O2) significantly influence its stability. Most metal ions do not impact the stability of WSSM, except for Fe2+, Fe3+, Al3+, and Cu2+, which result in the precipitation of WSSM. Additionally, WSSM exhibits remarkable antioxidant activity with IC50 values of 0.91, 0.56, and 0.52 mg/mL for scavenging superoxide anion radicals (O2-·), hydroxyl radicals (·OH), and DPPH radicals, respectively. It also demonstrates the ability to adsorb the heavy metal Cd2+, with the adsorption rate gradually increasing with a higher temperature and larger amounts of WSSM added. Infrared spectroscopy analysis reveals the weakening of characteristic peaks (-COOH and -OH) during the process of Cd2+ adsorption by WSSM, while SEM confirms surface roughening and structural damage after Cd2+ adsorption. This study provides valuable insights for the utilization of squid melanin products as natural antioxidants and heavy metal adsorbents in the food industry.

The Development of Highly pH-Sensitive Bacterial Cellulose Nanofibers/Gelatin-Based Intelligent Films Loaded with Anthocyanin/Curcumin for the Fresh-Keeping and Freshness Detection of Fresh Pork

The aim of this study was to develop highly pH-sensitive bacterial cellulose nanofibers/gelatin-based intelligent films, where the intelligent films were loaded with different ratios (10:0, 0:10 2:8, 5:5 and 8:2, w/w) of curcumin:anthocyanin (Cur/ATH), and the characterization of intelligent films was investigated. The results showed that the microstructures of intelligent films were much rougher as the proportion of curcumin increased. FTIR results showed that anthocyanin and curcumin were fixed in gelatin matrix by hydrogen bonds. Moreover, XRD results showed that curcumin had a significant effect on the crystal structure of the films. Interestingly, films loaded with a Cur/ATH ratio of 5:5 had the best mechanical and antioxidant properties and a high pH-sensitivity property. Consequently, the bacterial cellulose nanofibers/gelatin-based intelligent films loaded with a Cur/ATH ratio of 5:5 were used for the packaging of fresh pork, displaying good fresh-keeping and freshness detection effects. Therefore, this study suggested that bacterial cellulose nanofibers/gelatin-based intelligent films have great potential in the fresh-keeping and freshness detection of meat.

Progress on molecular modification and functional applications of anthocyanins

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

Azo dyes in the food industry: Features, classification, toxicity, alternatives, and regulation

Azo dyes, including Tartrazine, Sunset Yellow, and Carmoisine, are added to foods to provide color, but they have no value with regard to nutrition, food preservation, or health benefits. Because of their availability, affordability, stability, and low cost, and because they provide intense coloration to the product without contributing unwanted flavors, the food industry often prefers to use synthetic azo dyes rather than natural colorants. Food dyes have been tested by regulatory agencies responsible for guaranteeing consumer safety. Nevertheless, the safety of these colorants remains controversial; they have been associated with adverse effects, particularly due to the reduction and cleavage of the azo bond. Here, we review the features, classification, regulation, toxicity, and alternatives to the use of azo dyes in food.

The Effects of Citric Acid Crosslinking on Fabrication and Characterization of Gelatin/Curcumin-Based Electrospun Antioxidant Nanofibers

Nanofibers, produced through the novel method of electrospinning, have a high ratio of surface area to volume, which allows them to have different optical, electrical, thermal, and mechanical properties than macroscale materials. In this study, it was aimed to produce nanofibers with gelatin and curcumin. The effects of gelatin concentration and crosslinking with citric acid on the characteristics of electrospun nanofibers were studied. Gelatin film containing neither citric acid nor curcumin was used as control. Solutions were evaluated by solution conductivity, color analysis, and rheological properties. Obtained nanofibers were characterized by morphological analysis (SEM), antioxidant activity (AA), thermal properties (TGA, XRD, DSC), water vapor permeability (WVP), and Fourier transform infrared (FTIR) analysis. It was found that the functional groups of gelatin were not changed significantly but some degree of crosslinking was seen, as indicated by the changes in AA, crystallinity, etc. Improvement in antioxidant activities was seen, which was the highest for gelatin and curcumin films (32%). The highest melting temperature (78 °C) and WVP (2.365 × 10^-10 gm^-1 s^-1 Pa^-1) was seen for gelatin and curcumin films crosslinked with 0.5% citric acid. Gelatin with curcumin films crosslinked with 1% citric acid showed the lowest crystallinity (1.56%). It was concluded that even though citric acid might not prove to be a stable crosslinking agent for the protein (gelatin), it contributed to the antioxidant nature of the films, along with curcumin. These films are promising candidates to be applied on cut fruits, to reduce water loss and oxidation and hence extend their shelf lives.

Use of carminic acid immobilized in agarose gel as a binding phase for DGT: A new approach for determinations of rare earth elements

Recently, rare-earth elements (REEs) have attracted great interest due to their importance in several fields, such as the high-technology and medicine industries. Due to the recent intensification of the use of REEs in the world and the resulting potential impact on the environment, new analytical approaches for their determination, fractionation and speciation are needed. Diffusive gradients in thin films are a passive technique already used for sampling labile REEs, providing in situ analyte concentration, fractionation and, consequently, remarkable information on REE geochemistry. However, data based on DGT measurements until now have been based exclusively on the use of a single binding phase (Chelex-100, immobilized in APA gel). The present work proposes a new method for the determination of rare earth elements using an inductively coupled plasma‒mass spectrometry technique and a diffusive gradients in thin films (DGT) technique for application in aquatic environments. New binding gels were tested for DGT using carminic acid as the binding agent. It was concluded that acid dispersion directly in agarose gel presented the best performance, offering a simpler, faster, and greener method for measuring labile REEs compared to the existing DGT binding phase. Deployment curves obtained by immersion tests in the laboratory show that 13 REEs had linearity in their retention by the developed binding agent (retention x time), confirming the main premise of the DGT technique obeying the first Fick's diffusion law. For the first time, the diffusion coefficients were obtained in agarose gels (diffusion medium) and carminic acid immobilized in agarose as the binding phase for La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Er, Tm, Yb and Lu, which were 3.94 × 10^-6, 3.87 × 10^-6, 3.90 × 10^-6, 3.79 × 10^-6, 3.71 × 10^-6, 4.13 × 10^-6, 3.75 × 10^-6, 3.94 × 10^-6, 3.45 × 10^-6, 3.97 × 10^-6, 3.25 × 10^-6, 4.06 × 10^-6, and 3.50 × 10^-6 cm² s^-1, respectively. Furthermore, the proposed DGT devices were tested in solutions with different pH values (3.5, 5.0, 6.5 and 8) and ionic strengths (I = 0.005 mol L^-1, 0.01 mol L^-1, 0.05 mol L^-1 and 0.1 mol L^-1 - NaNO₃). The results of these studies showed an average variation in the analyte retention for all elements at a maximum of approximately 20% in the pH tests. This variation is considerably lower than those previously reported when using Chelex resin as a binding agent, particularly for lower pH values. For the ionic strength, the maximum average variation was approximately 20% for all elements (except for I = 0.005 mol L^-1). These results indicate the possibility of a wide range of the proposed approach to be used for in situ deployment without the use of correction based on apparent diffusion coefficients (as required for using the conventional approach). In laboratory deployments using acid mine drainage water samples (treated and untreated), it was shown that the proposed approach presents excellent accuracy compared with data obtained from Chelex resin as a binding agent.

Plant Food Dyes with Antioxidant Properties and Allergies-Friend or Enemy?

Color is an important food attribute which increases its attractiveness, thus influencing consumer preferences and acceptance of food products. The characteristic color of fresh, raw food is due to natural dyes present in natural food sources. Food loses its natural color during processing or storage. Loss of natural color (e.g., graying) often reduces the appeal of a product to consumers. To increase the aesthetic value of food, natural or synthetic dyes are added to it. Interestingly, the use of food coloring to enhance food attractiveness and appetizing appearance has been practiced since antiquity. Food coloring can also cause certain health effects, both negative and positive. Dyes added to food, both natural and synthetic, are primarily chemical substances that may not be neutral to the body. Some of these substances have strong antioxidant properties. Thanks to this activity, they can also perform important pro-health functions, including antiallergic ones. On the other hand, as foreign substances, they can also cause various adverse food reactions, including allergic reactions of varying severity and anaphylactic shock. This article discusses food dyes of plant origins with antioxidant properties (anthocyanins, betanins, chlorophylls, carotenoids, and curcumin) and their relationship with allergy, both as sensitizing agents and immunomodulatory agents with potential antiallergic properties.

Designing nano ranged electrode modifier comprised of samarium niobate anchored carbon nanofibers for trace level detection of food colourant: Tartrazine

Tartrazine (TRZ) is a predominantly used food color in food processing industries which is soluble in water to produce a orange colour. This food colorant is categorized under the mono-azo pyrazolone dye group known for the perilous azo group (-NN-) attached to the aromatic ring that threatens human health. In consideration of these aspects, a novel TRZ sensing platform with advanced electrode material is designed by incorporating nanotechnology with chemical engineering. This innovative sensor is prepared by electrode modification through a nano ranged electrode modifier of SmNbO₄ decorated on the enmeshed carbon nanofibers. This is the first report on the investigation of SmNbO₄/f-CNF as an electrode modifier to extricate the superlative electrochemical properties towards TRZ detection and protracted its practicality to food samples with a lower limit of detection (2 nmolL^-1), broad linear range, good selectivity, and functional stability.

Effects of nitrite-rich and pigment-rich substitutes for sodium nitrite on the quality characteristics of emulsion-type pork sausages during cold storage

This study was conducted to evaluate the effects of nitrite-rich (celery powder; CP) and pigment-rich (purple sweet potato powder, PSP; red beet powder, RB) substitutes for synthetic sodium nitrite (CON) on the quality characteristics of emulsion-type pork sausages during four weeks of cold storage. Natural substitutes decreased the pH, lightness, and textural properties of pork sausages during storage (P < 0.05). Pigment-rich substitutes showed a decreased antioxidant effect after two weeks of storage when compared to the nitrite-rich groups (CON and CP; P < 0.05). Pigment-rich substitutes also accelerated the discoloration of pork sausages by increasing yellowness (RB and PSP) and decreasing redness (PSP) during storage (P < 0.05). However, these two pigment-rich substitutes showed different trends in redness (higher in PSP and lower in RB) and yellowness (higher in RB and lower in PSP) when compared to the nitrite-rich groups (CON and CP). Different types (nitrite-rich and pigment-rich) of natural substitutes for sodium nitrite had different effects on the quality characteristics of emulsion-type pork sausages throughout the four weeks of storage evaluated in this study.

Progress and Prospective of the Industrial Development and Applications of Eco-Friendly Colorants: An Insight into Environmental Impact and Sustainability Issues

Color is the prime feature directly associated with the consumer's attraction and choice of their food. The flavor, safety, and nutritional value of any food product are directly associated with the food color. Natural and synthetic colorants (dyes and pigments) have diversified applications in various sectors such as food, feed, pharmaceutical, textiles, cosmetics, and others. Concerning the food industry, different types of natural and synthetic colorants are available in the market. Synthetic food colorants have gained popularity as they are highly stable and cheaply available. Consumers worldwide prefer delightful foodstuffs but are more concerned about the safety of the food. After its disposal, the colloidal particles present in the synthetic colorants do not allow sunlight to penetrate aquatic bodies. This causes a foul smell and turbidity formation and gives a bad appearance. Furthermore, different studies carried out previously have presented the toxicological, carcinogenic effects, hypersensitivity reactions, and behavioral changes linked to the usage of synthetic colorants. Natural food colorings, however, have nutraceutical qualities that are valuable to human health such as curcumin extracted from turmeric and beta-carotene extracted from carrots. In addition, natural colorants have beneficial properties such as excellent antioxidant properties, antimutagenic, anti-inflammatory, antineoplastic, and antiarthritic effects. This review summarizes the sources of natural and synthetic colorants, their production rate, demand, extraction, and characterization of food colorants, their industrial applications, environmental impact, challenges in the sustainable utilization of natural colorants, and their prospects.

Aqueous Two-Phase Systems Based on Cationic and Anionic Surfactants Mixture for Rapid Extraction and Colorimetric Determination of Synthetic Food Dyes

In this study, aqueous two-phase systems (ATPSs) containing a cationic and anionic surfactants mixture were used for the preconcentration of the synthetic food dyes Allura Red AC, Azorubine, Sunset Yellow, Tartrazine, and Fast Green FCF. A rapid, simple, low cost, affordable, and environmentally friendly methodology based on microextraction in ATPSs, followed by spectrophotometric/colorimetric determination of the dyes, is proposed. The ATPSs are formed in mixtures of benzethonium chloride (BztCl) and sodium N-lauroylsarcosinate (NaLS) or sodium dihexylsulfosuccinate (NaDHSS) under the molar ratio close to equimolar at the total surfactant concentration of 0.01-0.20 M. The density, viscosity, polarity, and water content in the surfactant-rich phases at an equimolar ratio BztCl:NaA were determined. The effects of pH, total surfactant concentration, dye concentration, and time of extraction/centrifugation were investigated, and the optimum conditions for the quantitative extraction of dyes were established. The smartphone-based colorimetric determination was employed directly in the extract without separating the aqueous phase. The analytical performance (calibration linearity, precision, limits of detection and quantification, reproducibility, and preconcentration factor) and comparison of the spectrophotometric and smartphone-based colorimetric determination of dyes were evaluated. The method was applied to the determination of dyes in food samples and food-processing industrial wastewater.

Comparative Study of Cinnamon and Paprika Oleoresins Encapsulated by Spray Chilling and Particles from Gas Saturated Solutions Techniques: Evaluation of Physical Characteristics and Oleoresins Release in Food Simulated Media

In this study, cinnamon and paprika oleoresins were encapsulated by two technologies, respectively, spray chilling and particles from gas saturated solutions. Both technologies used palm oil as wall materials. The physical characteristics of the microparticles were compared as well as the oleoresins release behavior in high- and low-fat simulated food media. The spray chilling microparticles had an average diameter of 143.7 ± 1.5 µm, spherical shape, smooth surface, and passable flow property. In contrast, microparticles obtained by particles from gas saturated solutions (PGSS) showed an average diameter of 105.7 ± 0.6 µm, irregular shape, porous surface, poor flow property but higher encapsulation efficiency. In evaluating the compounds released in a simulated food medium, the spray chilling particles delivered 30.7%, while PGSS reached 23.1% after 1 h. Both microparticles well fitted the Kosmeyer-Peppas (R2 = 0.98 and 0.96 for spray chilling and PGSS) and Peppas-Sahlin models (R2 = 0.98 and 0.97 for spray chilling and PGSS). However, spray chilling microparticles showed a diffusion mechanism, while for PGSS ones erosion was the main mechanism. Despite the different physical characteristics, both microparticles proved to be possible facilitators in delivering oleoresins in food products.

Status of food colorants in India: conflicts and prospects

Food colorants are imperative ingredients for attracting consumers and in deciding their preferences. Here we discuss the current status of natural colorants and synthetic food colorants on the Indian market by appraising the growth of the food colorant market both globally and nationally, based on published case studies on synthetic food colorants (SFCs), rules, and regulations implemented by Food Safety and Standards Authority of India on natural food colorants and SFCs. The substantial lacunae in the research on the impacts of SFCs in the Indian population identified through our literature survey signify the scope and need for appraisal of the issues prevailing in the Indian food colorant market as well as the necessity of renewing the food colorant policies. The illegal use of banned food colorants, the adulteration of natural food colorants, mislabelling of SFCs as natural colorants, and the permitted use of internationally banned food colorants, as well as the unawareness among consumers are serious issues recognized. Appropriate labelling to denote natural food colorants' presence, renewed standards of policy to determine the permitted use of food colorants, comprehensive regulations for the production and use of natural food colorants, stringent rules to constrain the production of toxic SFCs are obligatory to breakdown the dilemma on the Indian food market. Most importantly, awareness and responsiveness should be generated among consumers regarding the illegal use and adulteration of colorants and the need to use natural colorants. We also recommend a logo to designate the presence of natural colorants which will aid the consumers to make the right choice.

Analytical Applicability of Graphene-Modified Electrode in Sunset Yellow Electrochemical Assay

Due to the recent increase in average living standards, food safety has caught public attention. It is necessary to conduct a qualitative and quantitative rapid test of prohibited food additives since the inclusion of food additives or the improper usage of synthetic dyes can negatively impact on the human health. Herein, a highly sensitive method for Sunset Yellow detection based on a glassy carbon electrode modified with few-layer graphenes was proposed. The electrochemical behavior of SY at the GR-exf/GCE modified surface was investigated by Cyclic Voltammetry, Square Wave Voltammetry, Electrochemical Impedance Spectroscopy and Amperometry. The influences of pH, scan rate, and interfering species were studied. Under optimized conditions, the developed sensor shows good linearity over a broad SY concentration range, e.g., 0.028-30 µM, with a low limit of detection (LOD = 0.0085 µM) and quantification (LOQ = 0.028 µM) (data obtained by amperometric technique). Furthermore, the modified electrode shows good selectivity, precision and sensitivity and has been successfully applied for SY quantification from commercially available pharmaceutical formulation as well as from candy bars and orange juice.

Tomato as a Natural Source of Dyes in the Food Industry: A Patent Data Analysis

BACKGROUND

Foods that promote health benefits are being increasingly used. Innovative techniques, such as nanotechnology, have been used to improve functional properties, sensory characteristics, or the conservation of foods.

OBJECTIVE

The objective of this study was to identify the technological domain of patents for tomato products with or without nanotechnology and elucidate the technological advances associated with the recent use of tomatoes as a natural food dye in the food industry by exploring patent documents.

METHODS AND RESULTS

The search was conducted using the Espacenet and INPI databases. There was an increase in patent document applications employing nanotechnology in 2013, with a peak between 2017 and 2018. China is the lead country in the number of patent applications. In Brazil, the patent applications are variable, and the food industry is most involved in studies on tomatoes as a natural food dye. Most patent deposits using nanotechnology were from companies, and the main sources of the patent application were the food and pharmaceutical industries.

CONCLUSION

There is an increasing trend for the use of tomatoes as natural food dyes, produced with or without nanotechnology, and number of patents filed yearly. New technologies are being developed in several application areas.

Aqueous Two-Phase Systems Based on Ionic Liquids and Deep Eutectic Solvents as a Tool for the Recovery of Non-Protein Bioactive Compounds—A Review

Aqueous two-phase systems (ATPS) based on ionic liquids (IL) and deep eutectic solvents (DES) are ecofriendly choices and can be used to selectively separate compounds of interest, such as bioactive compounds. Bioactive compounds are nutrients and nonnutrients of animal, plant, and microbial origin that benefit the human body in addition to their classic nutritional properties. They can also be used for technical purposes in food and as active components in the chemical and pharmaceutical industries. Because they are usually present in complex matrices and low concentrations, it is necessary to separate them in order to increase their availability and stability, and ATPS is a highlighted technique for this purpose. This review demonstrates the application of ATPS based on IL and DES as a tool for recovering nonprotein bioactive compounds, considering critical factors, results and the most recent advances in this field. In addition, the review emphasizes the perspectives for expanding the use of nonconventional ATPS in purification systems, which consider the use of molecular modelling to predict experimental conditions, the investigation of diverse compounds in phase-forming systems, the establishment of optimal operational parameters, and the verification of bioactivities after the purification process.

Biocolorants in food: Sources, extraction, applications and future prospects

Color of a food is one of the major factors influencing its acceptance by consumers. At presently synthetic dyes are the most commonly used food colorant in food industry by providing more esthetically appearance and as a means to quality control. However, the growing concern about health and environmental due to associated toxicity with synthetic food colorants has accelerated the global efforts to replace them with safer and healthy food colorants obtained from natural resources (plants, microorganisms, and animals). Further, many of these biocolorants not only provide myriad of colors to the food but also exert biological properties, thus they can be used as nutraceuticals in foods and beverages. In order to understand the importance of nature-derived pigments as food colorants, this review provides a thorough discussion on the natural origin of food colorants. Following this, different extraction methods for isolating biocolorants from plants and microbes were also discussed. Many of these biocolorants not only provide color, but also have many health promoting properties, for this reason their physicochemical and biological properties were also reviewed. Finally, current trends on the use of biocolorants in foods, and the challenges faced by the biocolorants in their effective utilization by food industry and possible solutions to these challenges were discussed.

Nutritionally Enriched Muffins from Roselle Calyx Extract Using Response Surface Methodology

Hibiscus sabdariffa, often called Roselle, is a flowering plant with a variety of traditional medicinal uses. Its calyx, with a bright and attractive red color, produces a tart and pleasant acidic taste. The purpose of this study was to develop a Roselle muffin and assess the acceptability, nutrition, and shelf life of the muffin using its ingredients. The muffin was developed using different formulations in different proportions resulting from Response Surface Methodology (RSM). Sensory parameters were used to assess the muffin's acceptability. According to the findings, the combination of extract volume 45.37 mL, citric acid 1.11 g, and sodium bicarbonate 1.67 g produces the best muffin, with the panelist's sensory scores reaching up to 84%. The outcome of the study suggests muffins baked with the Roselle calyx extract have high antioxidant (12.53 ± 0.13)%, anthocyanin (126.63 ± 1.96) mg Cyn-3-glu/100 g, phenolic (12.91 ± 0.69) mg GAE/100 g, and ascorbic acid (12.10 ± 0.89) mg/100 g contents. The microbial shelf life of the developed muffin is estimated to be 6 days at room temperature. The study findings can therefore be utilized in the development of foods containing Roselle calyx extract.

Addition of Chelators Increased the Stability of Black Rice Anthocyanins against the Metallic Ions in Tap Water and Improved the Coloration of Steamed Cold Noodles

The anthocyanins in black rice extract (BRA) are sensitive to metallic ions, which restrict its application in the coloration of steamed cold noodles in China that uses tap water as the solvent. Food-grade chelators were added to check if they could increase the stability of BRA. The results indicated that the color decay of BRA in tap water was mainly caused by Fe3+, Cu2+, and Fe2+, and the addition of chelators could effectively antagonize this effect. Coloration with the BRA solution containing the optimized chelator formulation of 0.01% ethylenediaminetetraacetic acid disodium, 0.08% sodium hexametaphosphate, and 0.064% sodium tartrate conferred comparable appearance and chromatic attributes with those of the noodle colored by deionized water-dissolved BRA. The steamed cold noodles colored by the chelators-containing BRA exhibited increased springiness and decreased starch retrogradation, and possessed potential health functions due to its slightly increased resistant starch content and markedly enhanced antioxidant capacity. Hence, the addition of chelators is a feasible way to increase the color stability of BRA in tap water, and the chelators-supplemented BRA could be used to produce steamed cold noodles with attractive color and health benefits.

Phycobiliproteins, the pigment-protein complex form of natural food colorants and bioactive ingredients

Currently, the use of synthetic pigments in foods is restricted since synthetic pigments are proven and suspected to be harmful to human health. Phycobiliproteins (PBPs), existed in phycobilisomes (PBSs) of algae, are a kind of pigment-proteins with intense color. The specific color of PBPs (red and blue) is given by the water-soluble open-chained tetrapyrrole chromophore (phycobilin) that covalently attaches to the apo-protein via thioether linkages to cysteine residues. According to the spectral characteristics of PBPs, they can be categorized as phycoerythrins (PEs), phycocyanins (PCs), allophycocyanins (APCs), and phycoerythrocyanins (PECs). PBPs can be used as natural food colorants, fluorescent substances, and bioactive ingredients in food applications owing to their color characteristics and physiological activities. This paper mainly summarizes the extraction and purification methods of the PBPs and reviews their characteristics and applications. Moreover, the use of several strategies such as additives, microencapsulation, electrospray, and cross-linking to improve the stability and bioavailability of PBPs as well as the future outlooks of PBPs as natural colorants in food commercialization are elucidated.

Encapsulation of Bilberry Extract with Maltodextrin and Gum Arabic by Freeze-Drying: Formulation, Characterisation, and Storage Stability

Anthocyanins are polyphenolic plant pigments associated with antioxidant and health-promoting properties. However, their application in the food industry is limited due to their poor stability. The purpose of this study was to encapsulate anthocyanin-rich bilberry (Vaccinium myrtillus L.) extract by freeze-drying and to investigate the effects of different wall materials and extract contents on the physicochemical and bioactive properties of the obtained encapsulates. Ethanolic bilberry extract was encapsulated with the use of maltodextrin (16.5–19.5 DE) (MD), gum Arabic (GA), and their combination in a 1:1 w/w ratio (MIX). Bilberry solids to wall material ratios were examined at 20:80, 30:70, and 40:60. All encapsulates showed an attractive red colour and low water activity values (aw ≤ 0.3) that indicated a low risk of microbial spoilage. In general, the biggest losses of total phenolic compounds and anthocyanins during three-week storage in the dark and at room temperature (20 ± 2 °C) were detected in the case of encapsulates with a higher content of bilberry extract (MIX30 and MIX40, and GA30 and GA40, respectively). The use of maltodextrin provided the best protection to bilberry anthocyanins during forced storage. Overall, the obtained encapsulates show suitable potential for the development of food products with added nutritional benefits.

Pulsed electric field assisted extraction of natural food pigments and colorings from plant matrices

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Pulsed electric field (PEF) technology enables the extraction of food pigments at lower temperatures.

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PEF process intensification may reduce the extraction yield depending on the plant matrix.

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Coupling PEF with other emerging technologies is a smart strategy to extract natural pigments.

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The application of PEF technology in natural food pigment extraction still requires further studies.

Coloring compounds are widely applied to manufacturing foods and beverages. The worldwide food market is replacing artificial colorants with natural alternatives, given the increased consumer demand for natural products. However, these substitutes are still an issue due to their high production cost and low chemical and physical stability. Furthermore, natural pigments are highly sensitive to processes applied in conventional extraction techniques, such as thermal, mechanical, and chemical stresses. In this regard, pulsed electric field (PEF) technology has emerged as a promising non-thermal alternative for recovering and producing natural colorings from food matrices. Its action mechanism on cell structures through the electroporation effect is a smart alternative to overcoming the challenging issues associated with producing natural colorants. In this scenario, this review provides an overview of the PEF assisted extraction of natural pigments and colorants, such as anthocyanins (red-blue-purple), betalains (red), carotenoids (yellow-orange-red), and chlorophylls (green) from plant sources. Moreover, the potential and limitations of this emerging technology to integrate the extraction process of natural colorants were discussed.