Betalain Extracts from Beetroot as Food Colorants: Effect of Temperature and UV-Light on Storability

Betalain-Chickpea Protein Particles Produced by Freeze Drying and Spray Drying: Physicochemical Aspects, Storage Stability, and In Vitro Digestion

Beetroots are one of the primary sources of betalains, nitrogenous pigments with anti-inflammatory and antioxidant properties. However, due to their chemical instability, betalains have limited use in food applications. This work investigated whether betalains encapsulated in chickpea protein could be stabilized and delivered in a shelf-stable format. Freeze-dried (CB-FD) and spray-dried (CB-SD) protein-betalain particles encapsulated in chickpea protein isolate (6% w/v) were prepared. The encapsulation method affected particles' morphology, water activity, hygroscopicity, solubility, and color. Particles captured total betalains of 9.30 ± 0.61 and 4.40 ± 0.92 mg/g for CB-SD and CB-FD, respectively. LC-MS identified 12 betacyanins and 6 betaxanthins. The stability of betalains revealed that encapsulation efficiently preserved betalain integrity of over 6 weeks of storage at 4, 22, and 40 °C compared to dry beetroot extract. CB-SD particles were stable with no significant changes, while CB-FD showed slight degradation after 4 weeks due to increased Aw. Antioxidant activity correlated well with betalain concentration. In vitro digestion resulted in only 25% bioaccessibility of betacyanins, while betaxanthins were more stable with 100% recovery. Encapsulation with chickpea protein isolate is an efficient and straightforward strategy for expanding and diversifying applications of phytochemical-rich beetroot extracts for the food industry.

Conservation Analysis and Colorimetric Characterization of Betalain Extracts from the Peel of Red Beetroot, Golden Beetroot, and Prickly Pear Applied to Cottage Cheese

The maintenance of betalains and the color of extracts from the peel of red beetroot (RBAC), golden beetroot (YBAC), and purple prickly pear (PBAC) were evaluated, describing the capacity of their use as natural pigments and in the formulation of attractive and functional foods. Betalain extracts were prepared as juices from frozen and dehydrated peel, adding organic acids and concentrating for water reduction. Extracts were evaluated and applied on cottage cheese, measuring the capacity of betalains retention and pigmentation, during 10 days of storage of closed and opened products. Extracts of RBAC showed the highest betacyanin concentration, followed by YBAC with betaxanthins and PBAC with less betacyanin content. The pH stability for the extracts was pH4-7; RBAC and PBAC were stables at <90 °C, whereas YBAC exposed >125 °C. Extracts were constant during 10 days under oxygen and light exposure; however, YBAC exhibited low resistance in this environment. With cottage cheese, extracts exposed no changes in betalains and color on closed products (10 days of storage at 4 °C). In opened products, PBAC maintained the maximum betalains and color at 90%, PBAC at 75%, and YBAC at 60%. The obtained data contributed to use of agro-industrial residues, betalain extraction and conservation, and their potential use in food coloration and stabilization.

Smart polymers and smartphones for Betalain measurement in cooked beetroots

Betalains in beetroots offer notable colouring properties and health benefits, including antioxidant, anti-inflammatory, hepatoprotective, and antitumorous activities. However, they degrade due to processing and storage conditions like temperature, pH, oxygen, and light-exposure. Traditional betalain determination methods are resource-intensive solid-liquid extractions. This study proposes a novel approach using a smart polymer to rapidly quantify betalains in processed beetroots. The polymer, containing N,N-dimethylaminoethyl methacrylate, selectively interacts with compounds like betalains. Characterization shows thermal stability over 250 °C and suitable mechanical properties. The film changes to colour upon interaction with betalains, allowing quantification via smartphone. The sensory polymer's efficacy was validated across 27 beetroot samples, showing no significant differences compared to traditional methods. Combining the smart polymer with a colour analysis app, "Colorimetric Titration," provides a robust and efficient means of quantifying total betalains in beetroot puree, reducing the quantification time from 180 to 90 min, promising implications for routine food industry quality assessments.

Betalains from vegetable peels: Extraction methods, stability, and applications as natural food colorants

Betalains are hydrophilic pigments naturally present in a limited number of plants and fungi. In addition to providing pigmentation, ranging from yellow to red, they show potential for replacing artificial food colorings. Betalains can be obtained from agri-food waste like vegetable peels through conventional and emerging extraction methods; however, they are susceptible to chemical changes due to various degradation factors, such as the presence of oxygen, light, and increased temperature. In this context, encapsulation can be used as a strategy to stabilize and reduce the pigment degradation rate for later industrial application in processed foods. This study reviews data from the last five years on the production and relevance of valuing agri-food waste, in addition to research carried out on betalains obtained from vegetable peels, such as extraction methods, encapsulation as a method of controlling stability and applications as colorant in food matrices, highlighting news insights for the field of pigments from plant sources. This review shows that encapsulation techniques using mixtures of wall materials offer superior protection than isolated materials. Despite advances in applicability, gaps still persist regarding stability in food matrices, especially on an industrial scale. However, future investigations should focus on filling the gaps regarding the maintenance of the properties of betalains for application in food industries as natural food coloring based on the precepts of circular economy and sustainable technology.

Stabilized chlorophyll-based food colorants from spinach: Kinetics of a tailored enzymatic extraction

An organic solvent-free method based on limited dosing options (biocatalyst and zinc chloride) for the quick and mild recovery of chlorophyll (Chl) from spinach has been proposed. This tailored, custom-made protocol has been designed to produce stable green natural colorants. The kinetics of pigment extraction turned out to be a very useful tool to identify the proper conditions, in terms of biocatalyst dose (0.10-50 U/g), extraction time (1-48h), and ZnCl2 amount (50-300ppm), both for enhancing the recovery yield and preserving the green color. Considering the extraction kinetics, the recovery yield, and the colorimetric data, the suitable conditions to produce stable green and food-grade colorants are 0.10 U/g of enzyme, 3h, and 150ppm of ZnCl2 at 25°C. The extraction yield of Chl (4863µg/U) was about 51% greater than control, with a higher extraction rate constant (5.43 × 10-4 g/(µg min)). Considering the impact of ZnCl2 amount on Chl, its protective action resulted to be more noticeable toward Chl a: at 150ppm, an increased amount of about 2.5 and 1.5 times was found for Chl a and Chl b, respectively, in comparison to the reference (0ppm ZnCl2). PRACTICAL APPLICATION: This research demonstrates how a suitable kinetic approach helps to provide a tailored protocol, customized for the vegetable matrix, to produce stable green natural colorants from spinach. Lowering enzyme dosage and ZnCl2 amount during the extraction of chlorophyll at low temperature is crucial for its potential use as a colorant in food industry, providing high economic values through saving time and environmental protection.

Ultrasound-assisted extraction and encapsulation of betalain from prickly pear: Process optimization, in-vitro digestive stability, and development of functional gummies

The study aimed to extract and encapsulate betalain pigment from prickly pear (Opuntia ficus-indica) using ultrasound-assisted extraction and eco-friendly glycerol. Subsequent analysis encompassed assessing its thermal stability, shelf-life, bio-accessibility, and biological properties. The process optimization employed Response Surface Methodology (RSM), focusing on glycerol concentration (20-50 %), sample to solvent ratio (1:10-1:20), temperature (30-60 °C), and time (10-30 min). Optimal conditions were determined as 23.15 % glycerol, 1:10 sample to solvent ratio, 10.43 min treatment time, and 31.15 °C temperature. Under these conditions, betalain content reached 858.28 mg/L with a 93.76 % encapsulation efficiency. Thermal stability tests (80-180 °C; 30 & 60 min) showed degradation of betalain with higher temperatures and longer durations, affecting the visual aspect (ΔE) of the pigment. Encapsulated betalain exhibited favorable shelf stability, with optimal storage life of 404.27 days at 4 °C in amber conditions, compared to 271.99 days at 4 °C without amber, 141.92 days at 25 °C without amber, and 134.22 days at 25 °C with amber. Bio-accessibility of encapsulated betalain was significantly higher (2.05 ± 0.03 %) than conventionally extracted pigment (1.03 ± 0.09 %). The encapsulated pigment displayed strong anti-inflammatory properties in dosages of 2-20 µL, with no cytotoxic effects. Additionally, incorporation into gummies was successful and visually approved by sensory panellists. Glycerol proved to be a green encapsulating agent for betalain, offering high shelf life and bio-accessibility, making it suitable for food industry applications. The encapsulated pigment demonstrated robust thermal stability and shelf life, making it suitable for food industry applications. This study highlights glycerol's potential as a sustainable alternative for natural pigment extraction.

Partitioning Recovery of Natural Pigments from Spirulina platensis

In the last few decades, the recovery of high-added value compounds with high food potential using microalgae as feedstock has been one of the main challenges for both research and industry. This study provides a simple, affordable, and cost-saving approach for the selective recovery of C-phycocyanin (C-PC), chlorophyll a and carotenoids from Spirulina platensis biomass by using biocompatible and industrially approved solvents (such as CaCl2 and ethanol). The concentration and yield of each pigment in the liquid extract have been spectrophotometrically detected, whereas the decolorized protein-rich biomass has been analyzed by CIELab parameters. The most concentrated (566.4 μg/mL) and food-grade C-PC extract (purity index 0.7) was obtained by applying a biomass/solvent ratio (1:10) for the first round of extraction (20 min), followed by a second round at 1:5 using CaCl2 1.5% (w/v) aqueous solution. Additionally, the same trial enabled the production of the brightest decolorized protein-rich biomass (L* = 46.2), characterized by a yellow-orange tonality (h° values = 81.3°).

Transcriptome analysis reveals the potential mechanism of carotenoids change in hepatopancreas under low-temperature storage from swimming crab (Portunus trituberculatus)

The hepatopancreas of swimming crab (Portunus trituberculatus) rich in carotenoids would undergo serious color deterioration during cold storage, and then made portunid lose its commodity value. In this study, we firstly elucidated the change mechanism of its carotenoids during storage at the molecular level using transcriptome technology. We concluded that low-temperature would inhibit aerobic respiration of portunid, leading to a lower pH and inducing the degradation of carotenoids. After that, longer cold storage time would increase the oxidative stress in portunid, resulting in a further decrease in carotenoids content. Finally, the strong autolysis of portunid could release carotenoids stored in other parts such as ovary to the external environment, resulting in the increase of carotenoids detection content. This research could provide a basis for further developing the fresh-keeping technology of portunid during low-temperature storage.

Inclusion of curcumin in b-cyclodextrin: a promising prospective as food ingredient

In the present work, the inclusion complexes between curcumin (CC) and β-cyclodextrin (β-CD) were obtained through co-precipitation at different times of magnetic stirring and simple mixing. The stoichiometric ratio between CC and β-CD was ascertained to be 1:2. The samples prepared by co-precipitation (24 h magnetic stirring and 24 h cold static precipitation) and by simple mixing, showed the best performance in terms of powder recovery (72 and 97%, respectively), encapsulation efficiency (72 and 95%, respectively) and tinting power, while no significant differences were revealed in terms of loading capacity (about 14%). Using either inclusion method, the complexation of CC into β-CD make the colorant 20-fold more water soluble than pure CC. The pigment stability was also enhanced under different storage conditions (high temperature and light exposure), either when applied in liquid or gel state. However, after 30 days under natural light exposure, an appreciable colour change from yellow to orange was revealed to an extent probably perceptible by an inexperienced observer.

Engineered Nanomaterials for Improving the Nutritional Quality of Agricultural Products: A Review

To ensure food safety, the current agricultural development has put forward requirements for improving nutritional quality and reducing the harmful accumulation of agricultural chemicals. Nano-enabled sustainable agriculture and food security have been increasingly explored as a new research frontier. Nano-fertilizers show the potential to be more efficient than traditional fertilizers, reducing the amount used while ensuring plant uptake, supplying the inorganic nutrients needed by plants, and improving the process by which plants produce organic nutrients. Other agricultural uses of nanotechnology affect crop productivity and nutrient quality in addition to nano-fertilizers. This article will review the research progress of using nanomaterials to improve nutritional quality in recent years and point out the focus of future research.

Sustainable Production and Characteristics of Dried Fermented Vegetables

The current fashion for healthy food and the increasing number of people with lactose intolerance make fermented vegetables increasingly important. On top of this, surpluses unused in the vegetable harvest can become a potential source of “green waste”. The use of fermentation and freeze-drying can result in a valuable, sustainable product that can solve the problems of spoiled vegetables and the need for refrigerated storage. Therefore, this study aimed to obtain sustainable dried fermented vegetables and to compare their selected physical and structural properties. Beetroot, carrot, and red pepper were selected for this purpose. These vegetables were subjected to a spontaneous lactic fermentation process. After the process, the vegetables were freeze-dried, and their structure and selected properties (color, dry weight, and the number of lactic acid bacteria) were determined. Fermented vegetables were found to differ from their raw sources in structure and color, the main discrepancies being shown by the b* factor (yellow-blue). Root vegetables had smaller pores of structure in the freeze-dried samples than red peppers. The freeze-drying process did not affect the number of bacteria. It can be concluded that both the fermentation and the freeze-drying processes affected the structure of the selected vegetables. All tested vegetables can be fermented and freeze-dried without major changes in color and microbiological properties and can be used as a potential source of lactic acid bacteria and health-promoting pigments, e.g., in the form of chips. In addition, their shelf life is extended.

The Impact of the Fermentation Method on the Pigment Content in Pickled Beetroot and Red Bell Pepper Juices and Freeze-Dried Powders

The beetroot and red bell pepper are vegetables rich in active ingredients, and their potential for health benefits are crucial. Both presented raw materials are rich in natural pigments, but are unstable and seasonal; thus, it was decided to take steps to extend their durability. Lactic fermentation has been recognized as a food preservation method, requiring minimal resources. The activities undertaken were also aimed at creating a new product with a coloring and probiotic potential. For this reason, the study aimed to evaluate the impact of the method of fermentation on the content of active compounds (pigments) in pickled juices and freeze-dried powders. The lactic acid fermentation guided in two ways. The second step of the research was to obtain powders in the freeze-drying process. For fermentation, Levilactobacillus brevis and Limosilactobacillus fermentum were used. In juices and powders, pigments, color, and dry matter were tested. In this research, no differences in fermented juice pigment contents were seen; however, the color coefficient differed in raw juices. The freeze-drying process resulted in lowering the pigment content, and increasing dry matter and good storage conditions (glass transition temperatures 48–66 °C). The selection of vegetable methods suggested the use of fermentation and mixing it with a marinade (higher pigments and lactic acid bacteria content). All powders were stable and can be used as a colorant source, whereas for probiotic properties, a higher number of bacteria is needed.