pigments found in vegetables and its extraction technique

7/31/2019 Pigments Found in Vegetables and Its Extraction Technique

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PIGMENTS FOUND INVEGETABLES AND ITS

EXTRACTION TECHNIQUE


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INTRODUCTION

The pigments found in plants playimportant roles in plant metabolismand visual attraction in nature. Theyare also important for humans,attracting our attention andproviding us with nutrients. Major

plant pigments include carotenoids,anthocyanins and other flavonoids,betalains, and chlorophylls.


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CAROTENOIDS

Carotenoids pigments are yellow, orangeor red, and play pivotal roles inphotosynthesis. Carotenoids are organicpigments that are naturally occurring in

chromoplasts of plants and some otherorganisms like algae, fungus and bacteria.There are over 600 known carotenoids.They absorb blue light. Carotenoids servetwo key roles in plants and algae: they

absorb light energy for use inphotosynthesis, and they protectchlorophyll from photo damage photo-oxidation and are accessory, light-harvesting pigments and photoreceptors.


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EXTRACTION OF CAROTENOIDS

Carotenoids are extracted fromplant matter by mixing the plantmatter and water to obtain amixture of no greater than 10 Bx,crushing the mixture to obtain apulp and a serum, and extracting

the pulp to obtain a carotenoidscontaining plant oleoresin.


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Carotenoids are found in

vegetables

Zeaxanthin, a powerful carotenoids

antioxidant

CAROTENOIDS


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CHLOROPHYLL

Chlorophyll are green pigments. Theyoccur in all green plants and are localizedin plastids. Chlorophylls capture light

energy and convert it into chemical energy.They rarely occur outside of photosynthetictissue. Chlorophyll absorbs light moststrongly in the blue and red but poorly in

the green portions of the electromagneticspectrum, hence the green color ofchlorophyll-containing tissues such as plantleaves.


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EXTRACTION OF CHLOROPHYLL

Chlorophylls and carotenes do not dissolvevery well in water, but they dissolve like inhexane. The other compounds do not dissolvewell in hexane, but dissolve well in water.Water and hexane do not mix. If you mixthem together, the hexane will form a layer ontop of the water because hexane is less densethan water. The differences in compound

solubility in water and hexane, and the factthat water and hexane form layers, and wecan separate the chlorophylls and carotenesfrom the water-soluble compounds. Aftervigorous shaking to mix the layers

temporarily, you will allow them to separate.


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CHLOROPHYLL


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ANTHOCYANINS

Anthocyanins are water-soluble flavonoidspigments that appear red to blue, according topH. They occur in all tissues of higher plants,providing color in leaves, stems, roots,flowers, and fruits, though not always insufficient quantities to be noticeable.Anthocyanins are most visible in the petals offlowers, where they may make up as much as

30% of the dry weight of the tissue. In plantslike Tradescantia zebrina; the anthocyanincatches light that has passed through the leafand reflects it back towards regions bearingchlorophyll, in order to maximize the use of

available light.


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EXTRACTION OF ANTHOCYANINS

The undesirable materials contained inanthocyanin extracts are removed bysubjecting the extracts to ultra filtrationor dialysis to remove low molecular

weight components from the extracts.The extracts are also subjected to ionexchange to remove additional of theseundesirable constituents..

They are also enhanced with oxidative

stability and photo stability. Suchprocessed anthocyanin extracts may havehigher tinctoral powers, and thus theymay be suitable for coloring various foodproducts.


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The purple color of flower is due to the presence of anthocyanins.

ANTHOCYANINS
http://en.wikipedia.org/wiki/File:Orange_violet_pansies.jpg


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BETALAINS

Betalains are a class of red and yellowin dole-derived pigments found in plantsof the Caryophyllales. They are mostoften noticeable in the petals of flowers,

but may color the fruits, leaves, stems,and roots of plants that contain them. Thedeep red color of beets, bougainvillea,amaranth, and many cacti results fromthe presence of betalain pigments.

Betalains may occur in any part of theplant, including the petals of flowers,fruits, leaves, stems, and roots.


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Betalains are

found in beetFlowers containingbetalains

BETALAINS
http://en.wikipedia.org/wiki/File:Cactus_in_Bloom_01.jpg


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pigments found in vegetables and its extraction technique

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