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Betalain is a water-soluble pigment contained in Caryophyllales plants. It not only holds potential as a natural food colorant but also offers various health benefits, acting as an antioxidant. This study focused on analyzing the pH-dependent stability of encapsulated betalain pigments extracted from red beetroot (Beta vulgaris L.) using methods such as absorption spectroscopy, HPLC, and LC-MS. The major pigments identified were vulgaxanthin I, betanin, isobetanin, and neobetanin, alongside minor components, including three betaxanthin species and a degradation product known as betalamic acid. Spectrophotometric analyses revealed that above pH 8, the betalain peak at 435 nm decreased and red-shifted to a peak at 549 nm, a shift that could be reversed through neutral pH treatment. At pH 11, a new broad peak appeared at 410 nm and was identified as betalamic acid. To assess the pH-dependency of each betalain, the targeted betalains were separated and quantified through HPLC after incubation across a wide pH range of 2-11 and during storage. After 3 days of storage in highly alkaline conditions (pH 10-11), major betalains, with the exception of neobetanin, underwent significant degradation. Conversely, these pigments displayed relative stability in acidic conditions. In contrast, neobetanin showed vulnerability to acidic conditions but exhibited tolerance to alkaline pH levels of 10-11. The degradation product, betalamic acid, demonstrated a similar susceptibility to alkaline pH as betanins. In conclusion, the significant stability decrease under highly alkaline conditions results not only from the hydrolytic reaction of betalains but also from the degradation of betalamic acid itself. PRACTICAL APPLICATION: Encapsulation methods are used to enhance the stability of betalains against temperature variations; however, the effects of pH, especially when considering individual betalain species, are not well understood. Despite betalains exhibiting similar features and being suitable for a wide pH range from acid to alkaline conditions, they are significantly affected by alkaline pH levels exceeding 10, as well as by storage duration. This study demonstrated the application of encapsulation to pH-dependent stability, and the findings offer valuable insights and a fresh perspective on betalains as red biocolorants, extending their potential application to a wide range of pH-controlled food products., (© 2024 Institute of Food Technologists.)

Betalains in bracts of Bougainvillea are of great application potential as natural food colorants and antioxidants. This study explored the color, spectra, composition, storage stability, and antioxidant properties of betalain-based Bougainvillea bracts extracts (BBEs) to verify their application value. The results showed that Bougainvillea bract color variance is due to varied contents and proportions of betacyanins (Bc) and betaxanthins (Bx). Bc or Bx alone determined hues of purple or yellow, respectively; the co-existence of Bc and Bx would produce varied hues of red. BBEs showed bright color and good antioxidant properties under a wide pH range. The pH range of 5−6 was optimal for the highest color stability, and pHs 3−8 were optimal for stronger antioxidants. Bc mainly underwent color fading during storage, while Bx easily produced dark precipitates or melanism under strong acidic (pH < 4) or alkaline conditions (pH > 8). However, Bougainvillea Bx showed 3−4 times higher antioxidant ability than Bc. Different considerations for Bc and Bx are needed for varied application purposes. The purple bracts containing only Bc would be more suitable as colorant sources, while additional Bx can bring enhancement of antioxidant ability and richness of Bougainvillea extract color.

Covering: 2001 to 2021Betacyanins cover a class of remarkable natural red-violet plant pigments with prospective chemical and biological properties for wide-ranging applications in food, pharmaceuticals, and the cosmetic industry. Betacyanins, forming the betalain pigment group together with yellow betaxanthins, have gained much attention due to the increasing social awareness of the positive impact of natural products on human health. Betalains are commercially recognized as natural food colorants with preliminarily ascertained, but to be further investigated, health-promoting properties. In addition, they exhibit a remarkable structural diversity based on glycosylated and acylated varieties. The main research directions for natural plant pigments are focused on their structure elucidation, methods of their separation and analysis, biological activities, bioavailability, factors affecting their stability, industrial applications as a plant-based food, natural colorants, drugs, and cosmetics as well as methods for high-yield production and stabilization. This review covers period of the last two decades of betacyanin research. In the first part of the review, we present an updated classification of all known betacyanins and their derivatives identified by chemical means as well as by mass spectrometric and NMR techniques. In the second part, we review the current research reports focused on the chemical properties of the pigments (decarboxylation, oxidation, conjugation, and chlorination reactions as well as the acyl group migration phenomenon) and describe the semi-synthesis of natural and artificial fluorescent betalamic acid conjugates, showing various prospective research directions.

Although betanin is commonly used as a water-soluble red colorant in foods, it is unstable when heated. In this study, the discoloration of betanin in a buffer solution was kinetically studied in the pH range of 2.6 to 7.6 at 40 °C to 80 °C. The absorption spectrum of betanin was deconvoluted into the spectra of betanin and its degradation product, betalamic acid. Subsequently, a reversible consecutive reaction, in which betanin was reversibly degraded to betalamic acid, and betalamic acid was further degraded, was assumed to calculate the first-order rate constant of each step. The apparent reaction mechanism varied depending on the pH values. Based on these rate constants, the activation energy of each process, as well as the equilibrium constant and enthalpy change for the reversible reaction between betanin and betalamic acid were evaluated., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Vegetable processing pomace contains valuable substances such as natural colors that can be reused as functional ingredients. Due to a large amount of water, they are an unstable material. The aim of our research was to assess how the pretreatment method (thermal or nonthermal) affects the properties of powders obtained from beet juice and pomace after the freeze-drying process. The raw material was steamed or sonicated for 10 or 15 min, and then squeezed into juice and pomace. Both squeezed products were freeze-dried. The content of dry substance; L*, a*, and b* color parameters; and the content of betalain pigments were analyzed. Pretreatments increased the proportion of red and yellow in the juices. Steam and ultrasound caused a significant reduction in parameter b* in the dried pomace. A significant increase in betanin in lyophilizates was observed after pretreatment with ultrasound and steam for 15 min. As a result of all experiments, dried juices and pomaces can also be used as a colorant source. However, there is higher potential with pomaces due to their additional internal substances as well as better storage properties. After a few hours, juice was sticky and not ready to use.

Neutrophils produce hypochlorous acid (HOCl) as well as other reactive oxygen species as part of a natural innate immune response in the human body; however, excessive levels of HOCl can ultimately be detrimental to health. Recent reports suggest that betacyanin plant pigments can act as potent scavengers of inflammatory factors and are notably effective against HOCl. Comparison of the in vitro anti-hypochlorite activities of a novel betalain-rich red beetroot ( Beta vulgaris L.) extract with its pure betalainic pigments revealed that the extract had the highest anti-hypochlorite activity, far exceeding the activity of all of the betalainic derivatives and selected reference antioxidants. This suggests that it may be an important food-based candidate for management of inflammatory conditions induced by excessive HOCl production. Among all pigments studied, betanidin exhibited the highest activity across the pH range.

The possibility of obtaining a carmine or pink color on ordinary cooked ham by applying natural dyes from three plant species, namely red radish ( Raphanus sativus L.), hibiscus ( Roselle sabdariffa L.) and red beetroot ( Beta vulgaris L.), was investigated. The extracts were evaluated for the stability at physical-chemical parameters and subjected to cytotoxicity assays in the gastric cell line AGS Encapsulation of the extracts in soybean lecithin liposomes and maltodextrin microcapsules was performed. Lyophilized extracts before and after encapsulation in maltodextrin were applied in the formulation of ordinary cooked ham and used in a pilot scale of production. The color of cooked ham samples from different assays was evaluated visually and by colorimetry. The results suggest that the coloration of ordinary cooked ham obtained with extracts of red beetroot is very promising for future applications in this type of meat product.

Currently, the demand for natural colorants is increasing instead of synthetic colorants for foodstuff, because they are harmless to human health. Betalain is group of compounds containing nitrogen and water soluble pigment. Betalain is classified into two main classes, betacyanin which is the condensation of betalamic acid with cyclo-DOPA and betaxanthin which is the conjugation of amino acid or amines with betalamic acid. They are used to color various foods and medicines. Betalain is different from anthocyanin because betalains contain nitrogen in their structures. It is interesting to hear that betalains and anthocyanins are individually significant but they have not seen together in the same plant. Their stability influenced by various factors such as, temperature, pH, water activity and light. In this review basic chemistry of betalains, classes, subclasses, their sources and biosynthesis, factors affecting their stability, health and food industry applications are discussed. Moreover, mentioned work signifies the potent anticancer, antioxidant and antimalarial activities of betalains, furthermore provides a help to do more scientific work on it.

Betalains are nitrogenous red and yellow pigments found in a single order of plants, the Caryophyllales, and in some higher fungi. They are responsible for the colors observed in many ornamental plants, as well as in various food products, where they are used as natural colorants. Their nutritional properties and attractive colors make them an appealing target for metabolic engineering. This is further heightened by the limited availability of natural betalain sources, arising from their relative scarcity in the plant kingdom, particularly in edible plants. Recent progress in decoding their biosynthetic pathway has facilitated stable heterologous production of betalains in several plant and microbial systems. Here, we provide a brief review of recent advances and discuss current approaches and possible future directions in betalain metabolic engineering, including expanding the chemical diversity of betalains and increasing their yield, exploring new host organisms for their heterologous production, and engineering their secretion from the cell., (© 2019 The Authors. New Phytologist © 2019 New Phytologist Trust.)

Betalains are vacuolar pigments composed of a nitrogenous core structure, betalamic acid [4-(2-oxoethylidene)-1,2,3,4-tetrahydropyridine-2,6-dicarboxylic acid]. This compound consists of a chromophore substructure 1,7-diazaheptamethin. Betalamic acid condenses with imino compounds (cyclo-DOPA or its glucosyl derivatives), or amines and/or their derivatives to form a variety of betacyanins (violet) and betaxanthins (yellow), respectively. These pigments exhibit absorption maxima in between 532-550 nm and 457-485 nm, respectively. These colors are currently in use as food additives as they are bioactive and completely safe to consume. However, owing to poor stability, their potential application in pharmaceuticals and cosmetics is severely compromised. There is a lack of scientific reports highlighting their superior tinctorial strength including fluorescence, and their excellent water solubility. For widening the color spectrum and their usage, various betalain-rich extracts have been reviewed here, focusing on their matrix effects on stability vis-a-vis purified pigments of different structural make-up. This review also encompasses work carried out in the past related to stability/stabilization of betalains and future research direction for the same., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Betalains are vacuolar pigments composed of a nitrogenous core structure, betalamic acid [4-(2-oxoethylidene)-1,2,3,4-tetrahydropyridine-2,6-dicarboxylic acid]. Betalamic acid condenses with imino compounds (cyclo-l-3,4-dihydroxy-phenylalanine/its glucosyl derivatives), or amino acids/derivatives to form variety of betacyanins (violet) and betaxanthins (yellow), respectively. About 75 betalains have been structurally unambiguously identified from plants of about 17 families (known till date) out of 34 families under the order Caryophyllales, wherein they serve as chemosystematic markers. In this review, all the identified betalain structures are presented with relevant discussion. Also, an estimated annual production potential of betalains has been computed for the first time. In addition, mutual exclusiveness of anthocyanins and betalains has been discussed in the wake of new evidences. An inclusive list of betalain-accumulating plants reported so far has been presented here to highlight pigment occurrence and accumulation pattern. Betalain synthesis starts with hydroxylation of tyrosine to DOPA, and subsequent cleavage of aromatic ring of DOPA resulting to betalamic acid formation. This pathway consists of two key enzymes namely, bifunctional tyrosinase (hydroxylation and oxidation) and DOPA dioxygenase (O2-dependent aromatic ring cleavage). Various spontaneous cyclisation, condensation and glucosylation steps complement the extended pathway, which has been presented here comprehensively. The biosynthesis is affected by various ecophysiological factors including biotic and abiotic elicitors that can be manipulated to increase pigment production for commercial scale extraction. Betalains are completely safe to consume, and contribute to health., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Red cactus pear has significant antioxidant activity and potential as a colorant in food, due to the presence of betalains. However, the betalains are highly thermolabile, and their application in thermal process, as extrusion cooking, should be evaluated. The aim of this study was to evaluate the effect of extrusion conditions on the chemical components of red cactus pear encapsulated powder. Cornstarch and encapsulated powder (2.5% w/w) were mixed and processed by extrusion at different barrel temperatures (80, 100, 120, 140 °C) and screw speeds (225, 275, 325 rpm) using a twin-screw extruder. Mean residence time (trm), color (L*, a*, b*), antioxidant activity, total polyphenol, betacyanin, and betaxanthin contents were determined on extrudates, and pigment degradation reaction rate constants (k) and activation energies (Ea) were calculated. Increases in barrel temperature and screw speed decreased the trm, and this was associated with better retentions of antioxidant activity, total polyphenol, betalain contents. The betacyanins k values ranged the -0.0188 to -0.0206/s and for betaxanthins ranged of -0.0122 to -0.0167/s, while Ea values were 1.5888 to 6.1815 kJ/mol, respectively. The bioactive compounds retention suggests that encapsulated powder can be used as pigments and to provide antioxidant properties to extruded products.

Pulp (CP) and ultrafiltered (UF) cactus pear extracts were encapsulated with Capsul (C) by applying a central composite design (CP-C and UF-C systems) by spray-drying. To evaluate the effect of the extract, microparticles obtained under optimal conditions were characterised and stored at 60 °C. Betacyanin and betaxanthin encapsulation efficiency reached values above 98% for both systems studied. This efficiency was attributed to strong interactions between betalains and the polymer. Betalain degradation in CP-C and UF-C microparticles followed pseudo-first order kinetics. The betacyanin degradation rate constant was significantly higher for CP-C than for UF-C. These results suggested that the mucilage or higher sugar content of CP increased the hygroscopicity of the CP-C microparticles, leading to the degradation of betalain. The hydrolysis pathway was the main mechanism of betanin degradation during microparticle storage. These results demonstrate the potential utility of both CP-C and UF-C microparticles as natural colourants for healthy foods., (Copyright © 2014 Elsevier Ltd. All rights reserved.)