Principal Pigment Research Articles

Blooming Chemistry: Vinca as Your Pocket-Friendly pH Indicator

This study reveals the potential of Vinca flowers (in hues of red, purple, violet, pink, light pink, and white) as vibrant and effective natural acid-base indicators for titration experiments. By employing a cold extraction method with 70% ethanol, we successfully isolated anthocyanin pigments from these flowers and explored their pH sensitivity across a broad range (pH 1-14). The extracts displayed striking color changes: red/pink in acidic conditions (pH 1-3), colorless at pH 5, green hues in the mid-range (pH 7-9), and yellow in basic solutions (pH 11-14). Notably, the purple, red and violet extracts showed the most distinct color shifts. UV-vis spectroscopy confirmed that anthocyanins are the principal pigments, with additional sugar content also identified. In practical titration experiments, including NaOH vs. HCl, HCl vs. NH4OH, and NaOH vs. CH3COOH, the Vinca flower extracts provided clear and reliable color transitions, comparable to synthetic indicators like methyl red, methyl orange, and phenolphthalein. The pH endpoints observed with these natural indicators matched those obtained with synthetic counterparts, underscoring the accuracy and reliability of Vinca flowers as pH indicators. This innovative approach not only offers a sustainable alternative to synthetic indicators but also highlights the valuable application of plant-based pigments in both educational and practical settings for acid-base titrations.

Biology, morphology and taxonomy of a snail-feeding leech from North Carolina, USA, provisionally identified as Helobdella lineata (Verrill, 1874) (Glossiphoniidae): First evidence for extra-oral digestion in the Hirudinea.

This is a twelve-year longitudinal study of a common snail-feeding leech indigenous to the Albemarle region of northeastern North Carolina, USA. Based on contents of this paper the species is provisionally identified as Helobdella lineata (Verrill, 1874). For all practical purposes this is the first comprehensive description of this species. Particular attention is focused on variability of its dorsal papillae and variable pigment patterns within the Albemarle population. A total of 404 specimens were collected from 25 collecting stations in disparate parts of the region. Specialised leech traps set in these swamps were monitored regularly yielding unprecedented information on its morphology, ecology and general biology. This study recognises four principal pigment variants within the Albemarle region which, based on dissections, appear to represent a single biological species. Moreover, limited observations suggest that pigment variability is attributable primarily to adaptive camouflage to local surroundings. Methodologically it is emphasized in this paper that variable traits cannot serve as key taxonomic anchors. A proposed alternative diagnosis for identifying H. lineata is based entirely on more rigorous, non-variable characters. A significant finding is that H. lineata is most meaningfully understood in terms of specialist adaptation to feeding on snails. Furthermore, it is proposed that such adaptation required a major evolutionary shift within the foregut of this species. Evidence is presented that H. lineata uses uniquely large salivary cells to dissolves solid snail tissue into a semi-fluid state before ingestion via a specialised proboscis. This is the first example of extra-oral digestion in the Hirudinea.

Integrated Transcriptome and Metabolome Analyses Reveal Bamboo Culm Color Formation Mechanisms Involved in Anthocyanin Biosynthetic in Phyllostachys nigra.

Phyllostachys nigra has green young culms (S1) and purple black mature culms (S4). Anthocyanins are the principal pigment responsible for color presentation in ornamental plants. We employ a multi-omics approach to investigate the regulatory mechanisms of anthocyanins in Ph. nigra. Firstly, we found that the pigments of the culm of Ph. nigra accumulated only in one to four layers of cells below the epidermis. The levels of total anthocyanins and total flavonoids gradually increased during the process of bamboo culm color formation. Metabolomics analysis indicated that the predominant pigment metabolites observed were petunidin 3-O-glucoside and malvidin O-hexoside, exhibiting a significant increase of up to 9.36-fold and 13.23-fold, respectively, during pigmentation of Ph. nigra culm. Transcriptomics sequencing has revealed that genes involved in flavonoid biosynthesis, phenylpropanoid biosynthesis, and starch and sucrose metabolism pathways were significantly enriched, leading to color formation. A total of 62 differentially expressed structural genes associated with anthocyanin synthesis were identified. Notably, PnANS2, PnUFGT2, PnCHI2, and PnCHS1 showed significant correlations with anthocyanin metabolites. Additionally, certain transcription factors such as PnMYB6 and PnMYB1 showed significant positive or negative correlations with anthocyanins. With the accumulation of sucrose, the expression of PnMYB6 is enhanced, which in turn triggers the expression of anthocyanin biosynthesis genes. Based on these findings, we propose that these key genes primarily regulate the anthocyanin synthesis pathway in the culm and contribute to the accumulation of anthocyanin, ultimately resulting in the purple-black coloration of Ph. nigra.

Comparative Transcriptome and Metabolome Profiling Reveal Mechanisms of Red Leaf Color Fading in Populus × euramericana cv. 'Zhonghuahongye'.

Anthocyanins are among the flavonoids that serve as the principal pigments affecting the color of plants. During leaf growth, the leaf color of 'Zhonghuahongye' gradually changes from copper-brown to yellow-green. At present, the mechanism of color change at different stages has not yet been discovered. To find this, we compared the color phenotype, metabolome, and transcriptome of the three leaf stages. The results showed that the anthocyanin content of leaves decreased by 62.5% and the chlorophyll content increased by 204.35%, 69.23%, 155.56% and 60%, respectively. Differential metabolites and genes were enriched in the pathway related to the synthesis of 'Zhonghuahongye' flavonoids and anthocyanins and to the biosynthesis of secondary metabolites. Furthermore, 273 flavonoid metabolites were detected, with a total of eight classes. DFR, FLS and ANS downstream of anthocyanin synthesis may be the key structural genes in reducing anthocyanin synthesis and accumulation in the green leaf of 'Zhonghuahongye'. The results of multi-omics analysis showed that the formation of color was primarily affected by anthocyanin regulation and its related synthesis-affected genes. This study preliminarily analyzed the green regression gene and metabolic changes in 'Zhonghuahongye' red leaves and constitutes a reference for the molecular breeding of 'Zhonghuahongye' red leaves.

Spectrofluorimetric determination of chlorophyll a in arugula extracts

AbstractAs a principal pigment in plants, chlorophyll a (Chl a) is widely used to evaluate quality changes and senescence process during storage of leafy vegetables. The determination of Chl a in plant extracts by spectrophotometric methods using various empirical equations is often unreliable. Considering the sensitivity of fluorescence detection, we report here a simple, inexpensive spectrofluorimetric method that can detect and quantify Chl a in plant extracts. The fluorescence standard used for the quantitative determination of Chl a was isolated in our laboratory from the extract of Anthrospira platensis (Spirulina). The method proved to be reliable, fast, and low cost in a study of the influence of the most commonly used domestic storage conditions on Chl a degradation in fresh-cut arugula.

Carotenoid components and their biosynthesis in a bud mutant of Shiranui mandarin (Citrus reticulata Blanco) with citrine flavedo.

Carotenoids are secondary metabolite responsible for colored pigments in plants and microbes (Li et al., 2022). They are a class of C40 tetraterpenoids consisting of eight isoprenoid units, and can be classified into carotenes and xanthophylls on the basis of their functional groups (Saini et al., 2015). Carotenes can be linear (phytoene, phytofluene, and ζ‍-carotene) or branched (β‍-carotene and α‍-carotene). Xanthophylls comprise β,β‍-xanthophylls (β‍-cryptoxanthin, zeaxanthin, violaxanthins, and neoxanthin) and β,ε‍-xanthophylls (α-cryptoxanthin, α-carotene, and lutein). Citrus fruits are complex sources of carotenoids, which are the principal pigments responsible for the typical orange color of most types (Chen, 2020). The difference in total carotenoid content and the diversity of carotenoid isomer proportion also accounts for other colors of citrus fruits, such as yellow, red, and pink (Chen, 2020).

Pigments and Inks Applied in Juan Vespucci’s Portolan Chart (1520)

Not many manuscript maps have been the object of material analysis so far. A portolan chart, signed and dated by Juan Vespucci in 1520, was studied in this research, conserved at the Archivo General de Indias in Seville (Spain). It is made on parchment and depicts the coasts and islands of Europe and Africa. It is the oldest portolan chart made in Seville, being unusual in applying hand stamp for decorative figures. The map was analysed by different non-invasive techniques: infra-red and ultraviolet light, digital microscope and X-ray fluorescence (XRF). The main goals of this study were to identify the materials used, as well as to detect retouching or restoration work. Results showed that the entire parchment was first covered with a white layer made of lead white (Pb), calcite or gypsum (Ca). The principal pigments used were vermilion (Hg), yellow ochre (Fe), azurite (Cu) and a copper-based green pigment (Cu) and carbon black. The letters were probably written with an iron-gall ink (Fe, Cu). Very thin golden leaves were applied on a mixtion glue for gilded wind roses. Several retouches from the 19th/20th centuries were found using zinc and titanium whites and probably cobalt blue.

Betanin alleviates oxidative stress through the Nrf2 signaling pathway in the liver of STZ-induced diabetic rats.

Continuing hyperglycemia causes and exacerbate oxidative stress. Betanin as the principal pigment of red beet root has antioxidant, anti-inflammatory, and anti-diabetic properties. The purpose of this study was to investigate the potency of betanin on antioxidant defense in STZ-induced diabetic rats' livers. STZ at a single dose of 60mg/kg body weight was intraperitoneally injected and betanin (10, 20, and 40mg/kg/day) was administered orally for 28 days. Malondialdehyde (MDA), total antioxidant capacity (TAC), protein carbonyl (PC) levels, and the enzyme activity of superoxide dismutase (SOD), catalases and glutathione peroxidases (GPx) were evaluated in the liver. Furthermore, gene expression of Nrf2 and mentioned antioxidant enzymes were measured by Real-time PCR. Betanin (10 and 20mg/kg) significantly reduced PC levels and increased antioxidant enzyme activity in diabetic rats compared to the control diabetic group (P < 0.01). In comparison to the diabetic control group, all studied genes expression in diabetic rats were increased significantly with betanin at doses of 10 and 20mg/kg (P < 0.02). The increase in gene expression at 20mg/kg of betanin was significantly stronger than others (P < 0.015) except for the catalase (P = 0.201), that was almost the same. Moreover, treatment of diabetic rats with 20mg/kg of betanin could significantly increase TAC levels (P < 0.05) and decrease MDA levels (P < 0.001) compared to diabetic control group. Betanin could increase the antioxidant capacity of liver tissue associated with the Nrf2-mediated pathway in a dose-dependent manner.

Protocolo diagnóstico de las alteraciones de la pigmentación

Skin color mainly depends on its principal pigment, melanin, though blood flow and other chromophores also have an influence. As a consequence, skin pigmentation disorders may be due to abnormalities in any of these components. To approach the diagnosis of these hypopigmentations, the time of onset of the lesions is essential, along with use of a Wood's light. In turn, for hyperpigmentations, the approach is based on their distribution, distinguishing between circumscribed and diffuse variants.

English

The pigment content in Blue-green algae is a specific feature of each species. The pigment variation is specific features among microalgae. The paper aim to analyze cyanobacterial extracts of different Usar soil of Azamgarh and Varanasi, Uttar Pradesh. The main object here is the importance of the blue green algae especially because of the pigments present in this class of algae. Pigments from natural sources are gaining more importance mainly due to health and environmental issues. Algae contain a wide range of pigments. Three major classes of pigments are chlorophylls, carotenoids (carotenes and xanthophylls) and phycobilins (Phycocyanin and phycoerythrin). Our present study investigates the efficiency for phycobiliprotein pigment production from four different cyanobacteria Hapalosiphon sp., Phormidium sp., Anabaena sp. and Nostoc sp. The harvested and dried biomass was subjected to extract pigments using different solvents. Thin Layer Chromatography was performed from extracted pigments using Acetone as extraction solvents. And running solvent especially for phycocyanin pigment was optimized and concluded that Petroleum ether and Acetone in the ratio of 7:3. This paper presents the information about the natural pigments of cyanobacteria and how they can be extracted and identified using different procedures and spectrophotometry. It emphasizes that the principal algal pigments are Phycobilins, Chlorophylls and Carotenoids.

Expression of a Chromoplast-Specific Lycopene β-Cyclase Gene (CYC-B) Is Implicated in Carotenoid Accumulation and Coloration in the Loquat.

Carotenoids are the principal pigments in the loquat. Although the metabolic pathway of plant carotenoids has been extensively investigated, few studies have been explored the regulatory mechanisms of loquat carotenoids because knowledge of the loquat genome is incomplete. The chromoplast-specific lycopene β-cyclase gene (CYC-B) could catalyze cyclization of lycopene to β-carotene. In this study, the differential accumulation patterns of loquat with different colors were analyzed and virus-induced gene silencing (VIGS) was utilized in order to verify CYC-B gene function. Using a cloning strategy of homologous genes, a CYC-B gene orthologue was successfully identified from the loquat. At a later stage of maturation, CYC-B gene expression and carotenoids concentrations in the ‘Dawuxing’ variety were higher than in ‘Chuannong 1-5-9′, possibly leading to the difference in pulp coloration of loquat. Interference of CYC-B gene expression in the loquat demonstrated clear visual changes. The green color in negative control fruits became yellow, while TRV2-CYC-B silenced fruits remained green. CYC-B gene expression and total carotenoid content in the pulp decreased by 32.5% and 44.1%, respectively. Furthermore, multiple key genes in the carotenoid metabolic pathway synergistically responded to downregulation of CYC-B gene expression. In summary, we provide direct evidences that CYC-B gene is involved in carotenoid accumulation and coloration in the loquat.

Gastroprotective Effects of Betanin Against Ethanol-induced Gastric Ulcer in Rats

BackgroundBetanin is the principal pigment and active phytochemical constituent of beetroot. The protective roles of betanin are documented in the heart, kidney, liver, and lung, but its potential gastroprotective effect is not assessed thus far. A number of studies demonstrated that betanin could inhibit lipid peroxidation.ObjectivesThe current study aimed at investigating the gastroprotective effect of betanin in gastric ulcer induced by ethanol.MethodsIn the present study, a group of animals were treated with betanin (50, 100, and 200 mg/kg, orally) and the other group received ranitidine as a reference antiulcer agent. One hour later, the gastric mucosal ulceration was induced by oral administration of absolute ethanol and the rats were sacrificed one hour. The gastric ulcers were assessed by macroscopic and histopathological examinations. Also, gastric malondialdehyde (MDA) level and nitric oxide (NO) content were measured.ResultsOral administration of betanin 100 and 200 mg/kg of body weight prior to receiving ethanol significantly attenuated the number and length of gastric ulcers as compared to the ethanol group. Moreover, pretreatment with betanin could significantly decrease stomach MDA level and maintain stomach NO content similar to that of the control group. Histopathological examinations indicated that ethanol-induced gastric ulcer was attenuated by betanin and no significant difference was observed between the betanin (200 mg/kg) and ranitidine groups.ConclusionsThe findings indicated that betanin has gastroprotective effects on gastric ulcers, which could be related to attenuated lipid peroxidation and reestablished gastric NO content.

Crystal structure of phycocyanin from heterocyst-forming filamentous cyanobacterium Nostoc sp. WR13

Phycocyanin (PC) is the principal pigment protein in the light-harvesting antenna of cyanobacteria. Here the biochemical characterization and the 1.51 Å crystal structure of PC from cyanobacterium Nostoc sp. WR13 (Nst-PC) is reported. The P63 crystal lattice is composed of the minimal biological entities of Nst-PC, the (αβ)3 trimeric rings. The structure has been refined to R factor 11.5% (Rfree 15.4%) using anisotropic atomic B factors. A phylogenetic study shows that the α and β chains of Nst-PC are significantly clustered in a distinct clade with Acaryochloris marina. The structure was examined to look for any significant differences between Nst-PC and PC from non-desert species. Only minor differences were found in the chromophore microenvironments. The tentative energy transfer pathways in Nst-PC were modeled based on simple structural considerations.

Rembrandt's Old Woman Praying, 1629/30: A look below the surface using X‐ray fluorescence mapping

Rembrandt's painting Old Woman Praying, 1629/30, is the most valuable and exceptional work of art of the Residenzgalerie Salzburg (RGS). It is painted on a gilded copper plate with dimensions of only approximately 15 × 12 cm. The painting probably belongs to a series of three small‐scale tronies, all executed on gilded copper plates. This particular picture preparation, which represents a special feature in Rembrandt's work, is quite unusual in the history of art.Previous investigations on the comparable paintings The Laughing Man, 1629/30, in the Mauritshuis, The Hague and the Self Portrait, 1630, in the National Museum, Stockholm showed that the gilding of the copper plate was applied over a lead white ground.To characterize the painting in the RGS, X‐ray fluorescence (XRF) mapping was performed in a collaboration between the Research Office Residenzgalerie, Land Salzburg, the XGLab S.R.L, Milan, and the Conservation Science Department of the Kunsthistorische Museum Vienna (KHM). The results indicate a different structure for this painting than that used for The Laughing Man and the Self Portrait. The gilding was applied directly onto the copper plate, but with three areas with the gilding missing. It seems likely that in these sections, the gold was purposely removed to provide a different darker effect.XRF mapping yielded valuable insights into the structure of the painting and its technique as well as the principal pigments used for its composition.

Comprehensive analysis of wintersweet flower reveals key structural genes involved in flavonoid biosynthetic pathway

Wintersweet (Chimonanthus praecox (L.)), with an over-one-thousand-years long history in cultivation, is still a popular ornamental woody plant in China. The tepals of wintersweet flower are waxy in nature and the overall color of the flower is yellow, while the inner tepals range from yellow to red, which makes it an ideal plant to study floral color formation in ornamental shrubs. In our current work, HPLC analysis revealed that the principal pigments in tepals were the metabolite of flavonoids. All the tepals were containing quercetin, kaempferol 3‑O‑rutinoside and rutin while cyanidin‑3‑O‑glucoside and cyanidin‑3‑O‑rutinoside were only found in the in the red tepals. Moreover, we found the rutin as the principal component of all the pigments revealed. As well as in this study, a reference transcriptome library constructed from two varieties H29 and H64 flower. Further, 30 proteins of flavonoid biosynthesis pathway were identified in H29 flower using proteome analysis. Based on these dataset, the flavonoid biosynthesis pathway was also speculated. After quantitative analysis of gene expression, we found that ANS act as an on-off switch for the accumulation of red pigments and had positive correlations with various steps genes of the flavonoid pathway. This expression profiling demonstrates that no gene products compete for common substrates to redirect the metabolic flux in wintersweet. It is also demonstrated that high expression of F3′H would provide sufficient content of the precursor, dihydroquercetin, for both flavonol and anthocyanin biosynthesis. The results help us to deepen and enrich the gene resource of color formation in wintersweet flower, and provide specific breeding strategies for increasing diversity of flower color.

Anthocyanin and proanthocyanidin contents, antioxidant activity, and in situ degradability of black and red rice grains.

ObjectiveAn experiment was conducted to assess the antioxidant contents and activities of colored rice grains and to evaluate their nutritive characteristics in terms of chemical composition and in situ ruminal degradation.MethodsTen cultivars of colored rice grains (Oryza sativa L.) collected from several areas of Japan were studied, and control rice without pigment, maize, barley, and wheat grains were used as control grains. Their chemical compositions, pigment, polyphenol contents, total antioxidant capacity (TAC), and degradation characteristics were determined.ResultsThe starch contents of the colored rice grains were in the range of 73.5% to 79.6%, similar to that of the control rice grain. The black and red rice grains contained anthocyanin (maximum: 5,045.6 μg/g) and proanthocyanidin (maximum: 3,060.6 μg/g) at high concentrations as their principal pigments, respectively. There were significantly (p<0.05) positive relationships among the pigment contents, polyphenol content, and TAC values in the colored and control rice grains, indicating that the increase in pigment contents also contributed to the increased polyphenol content and TAC values in the colored rice grains. The dry matter and starch degradation characteristics, as represented by c (fractional degradation rate of slowly degradable fraction) and by the effective degradability, of the colored rice grains and the control rice grain were ranked as follows among commonly used grains: wheat>barley ≥rice>maize. The colored rice grains also included the most-digestible starch, since their potential degradable fraction and actual degradability at 48 h incubation were almost 100%.ConclusionColored rice grains have high potential to be used as antioxidant sources in addition to starch sources in ruminants.

De novo Assembly of the Camellia nitidissima Transcriptome Reveals Key Genes of Flower Pigment Biosynthesis.

The golden camellia, Camellia nitidissima Chi., is a well-known ornamental plant that is known as “the queen of camellias” because of its golden yellow flowers. The principal pigments in the flowers are carotenoids and flavonol glycosides. Understanding the biosynthesis of the golden color and its regulation is important in camellia breeding. To obtain a comprehensive understanding of flower development in C. nitidissima, a number of cDNA libraries were independently constructed during flower development. Using the Illumina Hiseq2500 platform, approximately 71.8 million raw reads (about 10.8 gigabase pairs) were obtained and assembled into 583,194 transcripts and 466, 594 unigenes. A differentially expressed genes (DEGs) and co-expression network was constructed to identify unigenes correlated with flower color. The analysis of DEGs and co-expressed network involved in the carotenoid pathway indicated that the biosynthesis of carotenoids is regulated mainly at the transcript level and that phytoene synthase (PSY), β -carotene 3-hydroxylase (CrtZ), and capsanthin synthase (CCS1) exert synergistic effects in carotenoid biosynthesis. The analysis of DEGs and co-expressed network involved in the flavonoid pathway indicated that chalcone synthase (CHS), naringenin 3-dioxygenase (F3H), leucoanthocyanidin dioxygenase(ANS), and flavonol synthase (FLS) play critical roles in regulating the formation of flavonols and anthocyanidin. Based on the gene expression analysis of the carotenoid and flavonoid pathways, and determinations of the pigments, we speculate that the high expression of PSY and CrtZ ensures the production of adequate levels of carotenoids, while the expression of CHS, FLS ensures the production of flavonols. The golden yellow color is then the result of the accumulation of carotenoids and flavonol glucosides in the petals. This study of the mechanism of color formation in golden camellia points the way to breeding strategies that exploit gene technology approaches to increase the content of carotenoids and flavonol glucosides and to decrease anthocyanidin synthesis.

Evaluation of processing effects on anthocyanin content and colour modifications of blueberry (Vaccinium spp.) extracts: Comparison between HPLC-DAD and CIELAB analyses

Colour is the first organoleptic property that consumers appreciate of a foodstuff. In blueberry (Vaccinium spp.) fruits, the anthocyanins are the principal pigments determining the colour as well as many of the beneficial effects attributed to this functional food. Commercial blueberry-derived products represent important sources of these healthy molecules all year round.In this study, blueberries were produced into purees comparing two homogenization methods and further heated following different thermal treatments. All the supernatants of the homogenates were monitored for pH. Then, the hydroalcoholic extracts of the same samples were characterized by CIELAB and HPLC-DAD analyses. These analytical techniques provide complementary information on fruit pigments content as a whole and on quali-quantitative profile of the single bioactive colorants. These data could be very interesting to know the best manufacturing procedure to prepare blueberry-derived products, well accepted by the consumers, while maintaining their healthy properties unaltered.

Colour changes of greenlip abalone (Haliotis laevigata Donovan) fed fresh macroalgae and dried algal supplement

Abalone colour is an important market trait in the seafood industry. Two experiments were conducted over 93days to test the effect of diet on the colour of the foot and shell of 1-year old greenlip abalone Haliotis laevigata. In Experiment 1, a commercial control diet and two species of fresh macroalgae (Gracilaria cliftonii and Ulva sp.) were used and each macroalgae species was either non-enriched or enriched with nutrients in the culture media. The shell of abalone fed the commercial diet and fresh Ulva sp. was green but abalone fed fresh G. cliftonii developed a brown shell. The fresh G. cliftonii increased shell colour purity while fresh Ulva sp. increased shell brightness. Feeding abalone with either fresh Ulva or fresh G. cliftonii produced yellowish foot. Nutrient enrichment of algae did not significantly affect the pigment contents in both macroalgae and abalone, and had minimal impact on the colour of shell and foot. With the exception of zeaxanthin, the pigment contents were significantly lower in fresh G. cliftonii than in fresh Ulva sp. Moreover, β-carotene was the main pigment in abalone fed both species of fresh macroalgae. In Experiment 2, the inclusion of dietary dried algae affected abalone colour. Three diets including a commercial control diet, a diet containing 3% dried Spirulina sp. and a diet containing 10% dried Ulva sp. were used. The shell of abalone fed dried Spirulina sp. was yellow-brown with higher colour purity while the shell remained light green in abalone fed dried Ulva sp. or the commercial control diet. The colour of abalone foot became bright yellow when abalone fed dried Ulva sp. Abalone fed dried algae contained β-carotene as the principal pigment. This study indicates that fresh macroalgae and dried algae supplementation in feed can change the colour of abalone foot and shell. Feed effect on shell colour was far more than on tissue colour. Feeding abalone with fresh G. cliftonii contributes to the formation of brown colour on the shell. Statement of relevanceFeed manipulation can change abalone shell and foot colour.

Alternative pathway implicated as an influencing factor in the synthesis of theaflavin

The principal pigments present in black tea, theaflavins (TF), have been indicated to be of potential clinical significance in various fields of research which has been hampered by the very low levels of TFs from black tea extractions, being the original method employed to acquire TFs. Forelle pear (44 µM TF/g dry weight/h) and Yacon leaf (65 µM TF/g dry weight/h) homogenates were tested for their TF synthesis capacity and found to have a larger TF synthesis capacity than a green tea leaf homogenate (26 µM TF/g dry weight/h) based upon the flavognost method. In an incubation system of green tea leaf extract utilizing endogenous enzymes present in Forelle pear and Yacon homogenates to synthesize TF, the formation of an unknown peak [m/z 563.1349; (23.95)5; C26H28O14] was detected by mass spectrometry with a molecular mass similar to TF. This is in contrast to TF being solely synthesized in an in vitro model incubation system using isolated catechins and purified Forelle pear polyphenol oxidase. The preferential formation of the unknown compound could explain the low levels of TFs in black tea.