Colour studies on fruit juice blends from Opuntia and Hylocereus cacti and betalain-containing model solutions derived therefrom

The visual appearance and pigment stability of fruit juice blends from Opuntia and Hylocereus cacti and of betalain-containing model solutions derived therefrom were investigated at pH values ranging from 3 to 7. All samples were found to be stable as indicated by betalain contents as well as hue and chroma values over the complete pH range monitored. Both the juice and the purified betaxanthin solution from Opuntia ficus-indica cv. ‘Gialla’ were characterised by yellowish hues, while the juice and the purified betacyanin solution from Hylocereus polyrhizus displayed purplish tonalities. By blending the betaxanthin and betacyanin stock solutions, tailor-made hues covering the entire spectrum from bright yellow (h° = 84) to purplish-blue (h° = 333) were successfully produced. Since mixtures from purified betalains did not provide colour shades different from those obtained with raw cactus fruit juices, the use of the latter should be preferred both because of consumer-friendly labelling and improved pigment stability.     

Thermal degradation of betacyanins in juices from purple pitaya [<Emphasis Type="Italic">Hylocereus polyrhizus</Emphasis> (Weber) Britton &; Rose] monitored by high-performance liquid chromatography–tandem mass spectometric analyses

Changes in betacyanin content and colour shade of juices from purple pitaya [Hylocereus polyrhizus (Weber) Britton & Rose] as affected by thermal processing and consecutive cold storage to allow pigment reconstitution were investigated. Pigments from purple pitaya displayed higher stability than earlier investigations on betalains suggested. A novel high-performance liquid chromatography method was established, allowing simultaneous detection of genuine pigments of purple pitaya juice together with their degradation products. In addition to previously described betanin cleavage products (betalamic acid, cyclo-dopa 5-O--glucoside) further degradation products generated after decarboxylation and/or dehydration of phyllocactin and hylocerenin, respectively, were found. Moreover, neobetanin was identified as a thermal degradation product of betanin for the first time. With this newly developed high-performance liquid chromatography method, heating of purple pitaya juice and a commercial pitaya juice concentrate was proven by the detection of thermal betacyanin degradation products that had not been described, so far.     

Betalainic and nutritional profiles of pigment-enriched red beet root (Beta vulgaris L.) dried extracts

Red beet root (Beta vulgaris L.) colourants (betalains) are available either as concentrates produced by evaporating beet juice under vacuum, or as powders made by spray-drying a concentrate. The degradation of the pigments is dependent upon temperature, duration of heat treatment, pH and water activity of a product. Recently, a new proprietary method of large-scale chromatographic purification of red beet root extract has been discovered and developed that allows the production of more concentrated betalain formulations. In order to trace the betalainic compositions of the new products in comparison to the currently in-use spray-, air- and freeze-dried concentrates, a chromatographic study on betalains and their degradation derivatives analysed by LC-DAD-ESI-MS/MS was performed. Additionally, nutritional characterisation of the extracts was accomplished.     

Functional properties of anthocyanins and betalains in plants,food, and in human nutrition

Anthocyanins and betalains play important roles both in plant physiology, visual attraction for pollinators and seed dispersers, but also in food mainly defining its aesthetic value. Since anthocyanin and betalain structures allow to predict only part of their appearance, additional chemical and anatomical functions are required to modulate the appearance of plants and coloured food. Physiological effects that the same pigments exert in plants are supposedly similar to those which they show in humans following ingestion of coloured food. Therefore, anthocyanins and betalains both in fresh and also processed fruit and vegetables serve two functions: They improve the overall appearance, but also contribute to consumers' health and well-being.     

Characterisation and determination of in vitro antioxidant potential of betalains from Talinum triangulare (Jacq.) Willd.

Talinum triangulare (Jacq.) Willd is an erect, succulent, perennial herb belonging to the family Portulacaceae. Under extreme environmental conditions, the plant produces betalain pigments which get accumulated in the stem region. Hence, in the present study, the betaxanthin and betacyanin patterns from different samples of T. triangulare have been investigated by applying high-performance liquid chromatography photo-diode array detection (HPLC-PDA) coupled with positive ion electro-spray mass spectrometry. Two betacyanins and two betaxanthins were identified in aqueous methanolic extract of flower, stem and leaf. Betanin, isobetanin, immonium conjugates of betalamic acid with dopamine and tyrosine were elucidated. The total betalain content was estimated by photometric analysis. In vitro antioxidant activity for the betalain extract determined by various methods revealed potent scavenging ability. The current work may possibly be considered beneficial in utilisation of the plant T. triangulare as a natural colourant in food and beverage industries.     

Matrix dependent impact of sugar and ascorbic acid addition on color and anthocyanin stability of black carrot,elderberry and strawberry single strength and from concentrate juices upon thermal treatment

Heat stability of strawberry, elderberry and black carrot juices prepared from concentrate and fresh plant material was investigated at pH 3.5 by heating at 95 °C for 2 and 4 h, respectively. The impact of added saccharides (glucose, fructose, sucrose) and ascorbic acid on 5-hydroxymethylfurfural (HMF) formation, browning together with the stability of anthocyanins and their color properties were assessed using high performance liquid chromatography coupled to diode array detection (HPLC-DAD) and ultraviolet–visible (UV–Vis) spectrophotometry. Thermal degradation products of anthocyanins and saccharides were identified using liquid chromatography coupled to multistage mass spectrometry (LC–MSⁿ). Pigment stability and color changes depended on anthocyanin structure and juice matrix. Whereas a slight but insignificant stabilizing effect of added sugars and ascorbic acid was observed in juice prepared from black carrot concentrate, obvious color differences were detected in strawberry and elderberry juices when ascorbic acid was added. Manually squeezed juices from fresh plant material showed higher color stability compared to juices prepared from concentrate which might be due to the retention of polymeric matrix compounds in the former. The data presented may contribute to the development of advanced technological processes for the production of coloring foodstuff and food with improved color stability.     

Biological Activities of Plant Pigments Betalains

Betalains are a family of natural pigments present in most plants of the order Caryophyllales. They provide colors ranging from yellow to violet to structures that in other plants are colored by anthocyanins. These include not only edible fruits and roots but also flowers, stems, and bracts. The recent characterization of different bioactivities in experiments with betalain containing extracts and purified pigments has renewed the interest of the research community in these molecules used by the food industry as natural colorants. Studies with multiple cancer cell lines have demonstrated a high chemopreventive potential that finds in vitro support in a strong antiradical and antioxidant activity. Experiments in vivo with model animals and bioavailability studies reinforce the possible role played by betalains in the diet. This work provides a critical review of all the claimed biological activities of betalains, showing that the bioactivities described might be supported by the high antiradical capacity of their structural unit, betalamic acid. Although more investigations with purified compounds are needed, the current evidences suggest a strong health-promoting potential.     

Effects of processing and storage on juice colour and betacyanin stability of purple pitaya (<Emphasis Type="Italic">Hylocereus polyrhizus</Emphasis>) juice

Purple pitaya (Hylocereus polyrhizus) fruits have been recently proposed as a promising source of betalains. In the present study, purple pitaya juice processing at pilot-plant scale is reported for the first time. Each processing step was examined in terms of juice colour and betacyanin retention. Lightness (L ^*) and hue angle (h°) values were strongly influenced by juice filtration, while chroma (C ^*) and betacyanin retention were most strongly altered by pasteurisation. Three systems of juice pasteurisation were evaluated. Betacyanin loss and colour alteration were minimal upon pasteurisation in an HTST system and a standard tubular heat exchanger, respectively. Additionally, storage experiments using mucilage-free purple pitaya juice were conducted. Whereas light exposure of unsupplemented samples resulted in significant pigment degradation, detrimental effects of light exposition were completely prevented by the addition of 1% ascorbic acid prior to storage. After 6 months, about 70% of the initial betacyanin content was retained in the presence of ascorbic acid, irrespective of illumination.     

Pigment pattern and expression of colour in fruits from different Hylocereus sp. genotypes

Pigment profiles, betalain contents, colour and pH-values were studied in fruits from five Hylocereus sp. genotypes originating from Costa Rica. Significant colour differences between fruit pulps from “Nacional” and “San Ignacio” were found for C^⁎-values and “Lisa” exhibited the most reddish tint h°. Whereas highest betalain contents were registered in “San Ignacio” and “Orejona”, lowest values were found in “Nacional”. Additionally, pigment patterns of the genotypes were found to differ: While “Lisa”, “Nacional” and “Orejona” were characterised by a similar betalain pattern, “Rosa” and “San Ignacio” were significantly different offering a valuable tool for genotype comparison. Moreover, “Rosa” showed the highest betanin and isobetanin contents, whereas phyllocactin and hylocerenin were predominant in “San Ignacio”. Apart from the newly reported betalains neobetanin and gomphrenin I, indicaxanthin was the first betaxanthin so far detected in pitaya fruits.Industrial relevanceNatural substitutes for synthetic colourants are increasingly gaining importance on the global market. In particular, the so-called colouring foodstuffs representing aqueous or oily plant extracts extend their market share with red-coloured preparations being particularly requested. In this regard, pitaya fruits from the genotype Hylocereus have been proposed as promising colour sources, recently. To secure the authenticity of the plant material, a reliable differentiation of pitayas from different origins is required. In addition, Hylocereus fruits may differ in their colour quality and pigment content, the knowledge of which is crucial for the selection of appropriate plants for an emerging pitaya market.     

Study on efficiency of betacyanin extraction from red beetroots

Red beetroots are rich in betalain pigments, which are divided into betacyanins (predominating in red beetroots) and betaxanthins. The objective of this work was to study efficiency of aqueous extraction of betacyanins from red beets. The experiment was conducted according to a central composite design, with the following variables: solvent pH (pH, 3.0–5.0), solvent‐to‐beetroot ratio (S/B, 1:1–5:1), solvent initial temperature (ST, 30–70 °C) and grinding time (GT, 2–10 min). Beetroots were ground with the solvent, filtered and evaluated for betacyanin contents. A highly significant model was obtained for betacyanin extraction efficiency (BEE), which was positively affected by ST and S/B, and inversely affected by pH. The most adequate extraction conditions were pH, 3.0; S/B, 5:1; ST, 70 °C and GT, 2 min. At such conditions, BEE was near 70%. The method is simple and produces a bright red–purple extract to be later dried or concentrated for use as a food colourant.     

Betalains Assay of Fermented Red Beet Root Extract by High Performance Liquid Chromatography

A high performance liquid chromatographic process was developed for betacyanin and betaxanthin pigments in a fermented red beet root extract. The method employs a reverse-phase microparticular C₁₈ column, ion pairing, and a methanol-water mobile phase, using a solvent gradient program. Spectrophotometric evidence and an enzymatic method were used to unequivocably identify peaks obtained from LC chromatograms. This accurate method for betalains separation and quantification was rapid and efficient. This method of assay enables the stability of the colorant in drug forms to be monitored routinely.     

红甜菜色素稳定性影响因素研究进展

红甜菜是一种营养价值较高的食用蔬菜,含有大量的红甜菜色素。红甜菜色素是一种水溶性、含氮的季胺型生物碱,核心结构为甜菜醛氨酸。红甜菜色素依据化学结构不同可分为两类:甜菜红素和甜菜黄素。红甜菜色素作为一种食用天然色素,已应用于多种食品,但由于稳定性较差,其在食品、营养保健品和化妆品等领域的潜在应用受到诸多限制。作者综述了红甜菜色素的组成及结构,详细阐述了pH值、光照、温度、氧气和降解酶对红甜菜色素质量分数和颜色的影响,同时阐明了甜菜红素受这些因素影响后在易降解位置发生脱糖基化、脱羧、脱氢、醛亚胺键水解和异构化等化学变化的途径及产物,为深入研究甜菜色素稳定性、扩大红甜菜及红甜菜色素的应用领域提供参考。     

Plant Betalains: Safety,Antioxidant Activity,Clinical Efficacy,and Bioavailability

Betalains are accepted food additives derived from vacuoles of plants belonging to about 17 families in the order Caryophyllales. These pigments are 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‐DOPA and/or its glucosyl derivatives) or amines and/or their derivatives to form violet betacyanins (for example, betanin) and yellow betaxanthins (for example, indicaxanthin), respectively. Till date, structures of 75 betalains have been elucidated from plants under the order Caryophyllales. The extracted betalains are safe to consume and they act as micronutrients in the body. In vitro studies to highlight radical‐scavenging activity, cell culture studies to assess cytotoxicity and absorption of betalains, and proven clinical efficacies are compiled in this review. The literature on biological activity has not been analyzed for a synthesis of safety, clinical efficacy, and bioavailability to arrive at the concentrations required for the purported health benefits. Most betalains are under‐utilized in pharmaceutical and cosmetic preparations due to poor stability and lack of scientific reports highlighting their superior tinctorial strength including flourescence, water solubility, and functional value alongside their bioavailability. This is the first comprehensive review on the dietary safety, biological activity and bioavailability of betalains. Based on this review, for future debate and input from health professionals, a human daily intake of betanin and indicaxanthin can be proposed at 100 and 50 mg, respectively.     

Impact of Thermal Treatment on Color and Pigment Pattern of Red Beet (Beta vulgaris L.) Preparations

ABSTRACT: The impact of heating at 85°C during 8 h on overall color and betalain pattern of red beet ( Beta vulgaris L. ssp. vulgaris ) juice was investigated. Although the hue angle of 358° in fresh juice was indicative of the typical red-purple appearance, heating for 8 h induced an unexpected shift to 62° resulting in a yellow-orange solution. To monitor the underlying structural alterations of betalains, a new high-performance liquid chromatography separation compatible with mass spectrometry was developed. Applying this method, 2 novel yellow neobetanin structures and 2 orange-red betanin degradation products were preliminarily identified, and neobetanin formation resulting from heat exposure was proven for the 1st time. These 5 compounds were held responsible for the orange shift of red beet juice during thermal treatment. The relevance of these findings for industrial beet processing was demonstrated by comparison of pigment patterns of heated red beet juice samples and a commercial concentrate. On the basis of these results, a scheme for the thermal degradation of betanin is proposed.     

Stability of yellow-orange cactus pear (<Emphasis Type="Italic">Opuntia ficus-indica</Emphasis> [L.] Mill. cv. ‘Gialla’) betalains as affected by the juice matrix and selected food additives

The impact of added ascorbic, isoascorbic, and citric acid on heat stability of cactus pear betalains was investigated at pH 4 and 6, respectively. To assess the influence of cactus pear juice matrix compounds such as sugars, organic acids, amino acids, and pectic substances on pigment stability, juice and purified pigment preparations derived therefrom were assayed separately. Immediately after heating at 85 °C for 1 h and a 24 h cool storage period, betalain retention, betanin and proline-betaxanthin isomerisation as well as overall colour changes were determined. Pigment stability and colour characteristics depended on type and concentration of the respective additive as well as on pH conditions. Interestingly, the stabilising effects of the additives under investigation were less pronounced in matrix-free pigment preparations compared to juice samples. Maximum pigment retention amounting to 79% was obtained when 0.1% citric acid was added to the juice at pH 6. For the first time, formation of 2-decarboxy-betanin upon thermal treatment of yellow-orange cactus pear juice being more distinct at pH 4 as compared to pH 6 is reported.     

甜菜红素提取、纯化、稳定性及抗氧化活性研究进展

甜菜红素广泛存在于苋科、藜科、紫茉莉科、仙人掌科以及商陆科等多种植物中。近年来,国内外关于甜菜红素抗氧化的研究和应用已经成为热点。本文综述了甜菜红素的结构、提取、纯化、稳定性以及其通过直接清除自由基、抑制脂质过氧化反应、络合金属离子、抑制氧化酶和炎症因子的表达、激活机体抗氧化体系等方面发挥的抗氧化作用,为更好地优化甜菜红素的提取和纯化工艺,更深入研究其抗氧化活性提供参考和理论依据。     

Impact of Thermal Treatment and Storage on Color of Yellow-Orange Cactus Pear (Opuntia ficus-indica[L.] Mill. cv. 'Gialla') Juices

ABSTRACT:  The impact of heating at 75, 85, and 95 °C during 60 min on overall color and betalain retention of yellow-orange cactus pear ( Opuntia ficus-indica [L.] Mill. cv. 'Gialla') juice after a 24-h color regeneration period was investigated. The addition of 0.1% isoascorbic acid prior to heating minimized color alteration as well as betalain degradation to a significant level. A correlation between the total betaxanthin retention and the indicaxanthin/isoindicaxanthin ratio was detected in heated juice samples, thus proving the indicaxanthin/isoindicaxanthin ratio as a valuable indicator of thermally treated cactus pear juices. Notably, the same ratio was instrumental for retrospectively calculating the initial betaxanthin content. Additionally, storage experiments over a period of 6 mo were conducted. Samples kept in the dark exhibited notably better color and pigment retentions as compared to illuminated samples. A significantly stabilizing effect was also observed in samples with isoascorbic acid fortification. While indicaxanthin and betanin were predominantly degraded through hydrolytic cleavage upon both heat exposure and storage, isomerization was only marginal for betanin. In contrast, 2-decarboxy-betanin formation was exclusively found for nonfortified heated samples while decarboxylated indicaxanthin could not be detected.     

Comparative Study of Fresh and Fermented Bilberry Juices–State and Modification of the Coloring Pigments

Rapid and direct methods for the determination of the coloring pigments were applied to fresh and fermented bilberry juices–Vaccinium myrtillius–as well as to their fractionation products isolated by preparative column chromatography. These methods were: bisulfite de-colorization, chromatic indices and analytical column chromatography for the appreciation of the different pigment states. Results obtained from these experiments gave an estimation and comparison of the states and the forms of the coloring pigments and underlined the effects of the physicochemical treatments such as condensation or degradation of pigments during fermentation, preservation and experimental procedures.     

Biphasic short time heat degradation of the blue microalgae protein phycocyanin from Arthrospira platensis

Stability of colorants is concerning for food coloring matrices, particularly for the only natural blue food coloring, phycocyanin. The Spirulina-based microalgal extract is mainly comprised of heat sensitive protein-chromophore complexes, C-phycocyanin and allophycocyanin. Although frequently encountered in food processing, the impact of short time heat treatments has not been studied systematically. Here, phosphate buffered phycocyanin solution was heated in batch and emerging continuous processing systems, both characterized with high surface-to-volume ratios allowing isothermal conditions with residence times down to 5 s. Absorption scans revealed biphasic degradation of phycocyanin color activity to about 30% within 30 s at T ≥ 70 °C. Kinetic modelling of the color decay via an nth order approach contradicts previously assumed linear first order kinetics with a best fitting empirical reaction order of n = 6. It shows that decay in phycocyanin color activity is not a single process but encompasses C-phycocyanin and allophycocyanin aggregate disintegration and denaturation.Industrial relevanceCentral to this study is the color stability of phycocyanin, which is a high value component, derived from the emerging food source microalgae. It is also the only naturally obtained blue food coloring available to the food industry. Insights could be gained on the color degradation kinetics by treating an industry relevant formulation in batch and emerging scalable continuous systems via micro process engineering. This data will directly support food research and development activities to optimize and minimize blue color losses within multiple product categories.     

Pumpkin oil cake protein as a new carrier for encapsulation incorporated in food matrix: Effect of processing,storage and in vitro digestion on bioactivity

In this paper, valorisation of pumpkin oil cake as source of new protein carrier material for encapsulation was examined in order to enrich real food products. Cookies were used as a model system for addition of encapsulates at three different levels: 10%, 15% and 20%. The physicochemical and sensory properties were investigated, as well as conditions of stability after storage, in terms of total phenolic and betalain content. Furthermore, antioxidant, α-glucosidase and ACE inhibitory potential of cookies was evaluated after simulated gastrointestinal digestion. The cookies showed good technological quality as well as acceptable sensorial properties. The addition of encapsulate increases the total phenolic and betalain contents and shoved significant stability during storage time. Novel peptides were produced after gastrointestinal digestion, which enhanced bioactive properties of enriched products through synergistic action with active compounds from beetroot juice. Obtained digest shoved significant antioxidant, antidiabetic and antihypertension activities, hence ensuring a potential healing effect that could be reached by consuming these cookies.