The localisation, intracellular transport, and biosynthetic regulation of betalain plant pigments

<p>This thesis investigates the localisation, transport and biosynthetic control of betalain plant pigments to compare with the extensively researched anthocyanins. Anthocyanins and betalains appear similar, yet no plant naturally contains both pigment types. Due to this mutual exclusivity, betalain pigments are thought to functionally replace anthocyanins in many Caryophyllales. However, minimal research has been conducted to support this replacement hypothesis, resulting in limited knowledge of betalain pigment distribution and biosynthesis. The following series of experiments have added to this body of knowledge. Localisation of betalains was compared with that reported for anthocyanins. Histological analyses of 12 different betalain-producing species revealed similar pigment localisation to that of anthocyanic species. Similarities in pigment localisation suggest that these pigment types may have similar functional roles. The histological analyses also found that betacyanins and betaxanthins had differential localisation in several taxa. Organ- or tissue-specific distribution of betalain compounds suggests differing biological functions for betaxanthins and betacyanins. Hypotheses on betalain transport were tested using transgenic Arabidopsis thaliana lines capable of producing anthocyanins (PAP1-5), betalains (DOD-6), or both (DOD-6 x PAP1-5). Betaxanthins appeared to use vesicular transport, as betaxanthins were detected in small circular bodies within the cytoplasm. Furthermore, this observation suggests that betaxanthin formation occurred outside of the vacuole. DOD-6 was also crossed with Arabidopsis mutants, tt12 and tt19, which are deficient in proteins required for flavonoid vacuolar transport. Betaxanthin accumulation was reduced in both lines. In addition, DOD-6 was treated with transport inhibitors that affect anthocyanin accumulation. These experiments demonstrated that betaxanthins can utilise known flavonoid transport mechanisms, at least in this artificial pigment system. Regulation of betalain biosynthesis was analysed using Swiss chard (Beta vulgaris subsp. cicla cv. ‘Bright Lights’). Betalain production was induced through physical wounding of the lamina in red and white Swiss chard lines. Betalain pigments were produced around the wounding sites in the red line but not in the white line. Transcript level changes of betalain and flavonoid biosynthetic genes in these tissues were measured using real-time quantitative polymerase chain reaction analyses. Betalain biosynthetic genes were not up-regulated in the red line even though red pigments visibly accumulated. Rather, these genes were already expressed in the red line prior to wounding. Biosynthetic control of betalains may either be earlier in the pathway or at the post-transcriptional level. In contrast, all three flavonoid biosynthetic genes were up-regulated in response to wounding, indicating that expression of flavonoid and betalain biosynthetic genes are not co-regulated in Swiss chard. The final set of experiments examined the function of the two Beta vulgaris DOD genes (DODA and DODA1). Both genes were transiently expressed in nivea Antirrhinum majus dorsal petals and vacuum infiltrated with the betalain precursor L-DOPA. Expression of DODA1 but not DODA appeared to produce betalains. DODA-like genes have been found in anthocyanin-producing species, suggesting that this gene may not be involved in betalain biosynthesis. The overall findings from this research indicate that betalain pigment evolution of may have involved the utilization of anthocyanin transport machinery, but the regulatory control of the two pathways appears different.</p>

The localisation, intracellular transport, and biosynthetic regulation of betalain plant pigments

<p>This thesis investigates the localisation, transport and biosynthetic control of betalain plant pigments to compare with the extensively researched anthocyanins. Anthocyanins and betalains appear similar, yet no plant naturally contains both pigment types. Due to this mutual exclusivity, betalain pigments are thought to functionally replace anthocyanins in many Caryophyllales. However, minimal research has been conducted to support this replacement hypothesis, resulting in limited knowledge of betalain pigment distribution and biosynthesis. The following series of experiments have added to this body of knowledge. Localisation of betalains was compared with that reported for anthocyanins. Histological analyses of 12 different betalain-producing species revealed similar pigment localisation to that of anthocyanic species. Similarities in pigment localisation suggest that these pigment types may have similar functional roles. The histological analyses also found that betacyanins and betaxanthins had differential localisation in several taxa. Organ- or tissue-specific distribution of betalain compounds suggests differing biological functions for betaxanthins and betacyanins. Hypotheses on betalain transport were tested using transgenic Arabidopsis thaliana lines capable of producing anthocyanins (PAP1-5), betalains (DOD-6), or both (DOD-6 x PAP1-5). Betaxanthins appeared to use vesicular transport, as betaxanthins were detected in small circular bodies within the cytoplasm. Furthermore, this observation suggests that betaxanthin formation occurred outside of the vacuole. DOD-6 was also crossed with Arabidopsis mutants, tt12 and tt19, which are deficient in proteins required for flavonoid vacuolar transport. Betaxanthin accumulation was reduced in both lines. In addition, DOD-6 was treated with transport inhibitors that affect anthocyanin accumulation. These experiments demonstrated that betaxanthins can utilise known flavonoid transport mechanisms, at least in this artificial pigment system. Regulation of betalain biosynthesis was analysed using Swiss chard (Beta vulgaris subsp. cicla cv. ‘Bright Lights’). Betalain production was induced through physical wounding of the lamina in red and white Swiss chard lines. Betalain pigments were produced around the wounding sites in the red line but not in the white line. Transcript level changes of betalain and flavonoid biosynthetic genes in these tissues were measured using real-time quantitative polymerase chain reaction analyses. Betalain biosynthetic genes were not up-regulated in the red line even though red pigments visibly accumulated. Rather, these genes were already expressed in the red line prior to wounding. Biosynthetic control of betalains may either be earlier in the pathway or at the post-transcriptional level. In contrast, all three flavonoid biosynthetic genes were up-regulated in response to wounding, indicating that expression of flavonoid and betalain biosynthetic genes are not co-regulated in Swiss chard. The final set of experiments examined the function of the two Beta vulgaris DOD genes (DODA and DODA1). Both genes were transiently expressed in nivea Antirrhinum majus dorsal petals and vacuum infiltrated with the betalain precursor L-DOPA. Expression of DODA1 but not DODA appeared to produce betalains. DODA-like genes have been found in anthocyanin-producing species, suggesting that this gene may not be involved in betalain biosynthesis. The overall findings from this research indicate that betalain pigment evolution of may have involved the utilization of anthocyanin transport machinery, but the regulatory control of the two pathways appears different.</p>

Bioactive Betalain Extracts from Cactus Pear Fruit Pulp, Beetroot Tubers, and Amaranth Leaves

Natural food items and the additional benefits they provide have received considerable attention in recent years. Betalains are nutritious pigments which have valuable biological properties, e.g., antioxidant and free radical scavenging activity. In this study, aqueous betalain extracts were obtained from different coloured cactus pears (purple, red/pink, and orange), amaranth, and beetroot, with and without the addition of ascorbic acid, microwave-heated, and freeze-dried and subsequently analysed by thin layer chromatography (TLC). Beetroot samples without the addition of ascorbic acid (AA) had lower phenols, flavonoids, and ascorbic acid content than beetroot samples extracted with the addition of AA. Amaranth had significantly higher contents of antioxidants than all the other plants. Results for phenolic compounds showed that there were no significant differences between cactus pear cultivars, however, significant differences were seen between the two beetroot samples (microwave-heated with and without AA) as well as amaranth. For flavonoid compounds, amaranth had significantly higher values than all other samples. The lowest flavonoid content was found in beetroot without AA (0.49 mgCE/g). For ascorbic acid, significant differences were noticed between amaranth (71.71 mg/100 g) and samples from cactus pear and beetroot. TLC results showed that purple and red cactus pear samples had the most vivid colours, a reflection of the high betacyanin and betaxanthin contents in the cultivars. Moreover, extracts from cactus pear, beetroot, and amaranth were classified according to a decision tree which was designed by the Code of Federal Regulations/Food Additives Regulation of the EU. The classification of betalain pigment extracts as colouring foods was achieved through enrichment factor calculations and the colourant decision tree. The results showed that the betalain pigment extraction method used is inexpensive, time-saving, energy-saving, non-toxic, and chemical solvent free and yields high concentrations of betalains.

Red-beet betalain pigments inhibit amyloid-beta aggregation and prevent the progression of Alzheimer’s disease in a Caenorhabditis elegans model

Betalain pigments are mainly produced by plants in the order Caryophyllales. The biological functions of betalain pigments have gained recent interest; antioxidant, anti-inflammatory, and anticancer activities have been reported. To explore the biological effects of betalain pigments, we investigated the effects of betalain pigments derived from red-beet on amyloid-β (Aβ) aggregation, which is one of the causes of Alzheimer’s disease (AD). We conducted a ThT fluorescence assay, which revealed that red-beet betalain extract significantly suppressed the increase in fluorescence derived from Aβ aggregation compared the control. Observations using transmission electron microscopy confirmed that Aβ fibers and amorphous aggregation were reduced in the betalain pigment treatment. Furthermore, we performed a trait investigation using a nematode model of AD and found that the progression of symptoms was significantly suppressed in the group that ingested betalain pigment. These results suggest that betalain pigment may suppress the progression of AD.

Coloring of food by the use of natural color extracted by beetroot (Beta Vulgaris), betalain pigment

Color is one of the most important quality attribute in the food products. The purpose of adding color in the foods is to make them attractive, to influence the consumer to buy the product and also to improve the quality of the food product. At the present time the demand of natural color is increased in worldwide due to the awareness of people on therapeutic medicinal properties and their benefits in the place of synthetic colors. Synthetic colors are harmful for health and show toxicity in food products. Natural color are those pigments which is derived from naturally sources such as plants, insects, animals, vegetables and fruits etc. among all these natural dyes, plant based pigments have medicinal values so are mostly preferred. Today the food industry are mostly preferred the use of natural coloring pigment in their food products because the generation of this time is very possessive to their health and preferred the food product which is made from the use of natural color. The present study is based on the use of natural colors in food product in the place of synthetic color. The natural color was extracted from beetroot (Beta Vulgaris) named as betalain pigment. Betalain pigment is rich in antioxidant property, vitamin A and C and also a good source of iron, calcium etc. In this experiment the use of the natural color in the preparation of cookies.Keywords: natural food color, dyes, extraction, pigment, beetroot, betalain, cookies.

ORGANOLEPTIC TEST OF NOODLE FROM BROWN SEAWEED EXTRACT SUBTITUTION

Red dragon fruit peel has not been used in food processing. Red dragon fruit peel is a source of betalain pigment which can be used as natural colorant in food. Red dragon fruit peel contains antioxidants, antimicrobials, and fibers that are very beneficial for human health. Betalain pigment is unstable at high temperatures, so the application of red dragon fruit peel on food products in this study were jam, kue ku (a kind of Indonesian traditional cake), ice cream and rolled pan cake. The aim of the research was to analyze the quality of food products using red dragon fruit peel. This research was an experiment by using a single factor of complete randomized design. The primery data were collected from 30 panelists and analyzed by variant (ANAVA). If it was significantly different, the Duncan test was done. The result of the research showed that betalain pigment affected to the color, texture, and taste to all products

A Study of Photocatalytic Degradation of Betalain Pigment from Kitchen Waste, Semiconductive Nanostructured TiO2 Used as a Photocatalyst

Well crystallinenanostructured TiO2 powder was synthesised by Co-precipitation method using Titanium (IV) isopropoxide and CTAB are precursor materialsto maintain in 1:1 ratio concentration. The synthesised power was structurally, morphologically and optically analysed to using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM) and UV-Vis absorption spectra. The betalain pigment of polluted water was prepared from Beta vulgaris extract at room temperature (RT). The 89% of betalain pigment was degraded at 40 min from Beta vulgaris extract polluted water using as-prepared TiO2 powder as a photocatalystmaterial under visible light.