Simple facts about Betalain

Betalains are alkaloid pigments which are found in some families of plants belonging to the order Caryophyllales, but in no other plants.

They are named after the Beet family of plants (Beta).

Betalains are not found in plants containing anthocyanin pigments. Structurally they are unrelated. Unlike anthocyanins, they are not pH indicators as their colour is stable over a wide range of pH.  They are oxidised over time going brown in colour. This can be prevented by 0.1% ascorbic acid.

They have also been found in some fungi too e.g. Fly Agaric (mushroom)

Betalains can be divided into two types as betacyanins and betaxanthins; based upon their molecular structure.

Betacyanins

Usually appear red to red violet in colour (absorbance in 535-550nm)

Betaxanthins

Usually appear yellow in colour (absorbance in 475-480nm)

Betalains are found in the vacuole and they are water-soluble.

Also they cause colour in both flowers, fruits and sometimes vegetative organs

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Beetroot contains 2 Betacyanins. Thay are Betanin and a derivative.

Not much is known about the role of betalains. Commercially they are sometimes used as food colourants. As a food dye it’s cheap and no all allergic side effects are figured out yet.

Basic structure of betalain

Preparation of Sodium Carbonate extract - Identify Sulfates, Nitrites, Nitrates and Phosphates by using the prepared Sodium carbonate solution

Preparation of Sodium Carbonate extract

200mg of the unknown sample, 1g of Na₂CO₃ and 50ml of distilled water was added into a clean dry flask later boiled using a tripod stand. This was done by clamping a funnel above the flask to reduce evaporation.

It was boiled for about 5 minutes.

Afterwards solution was cooled and filtered using a filter paper.

A colorless filtrate was obtained.

Identify Sulfates, Nitrites, Nitrates and Phosphates by using the prepared Sodium carbonate solution

SO₄^2-

Procedure	Observation
5 drops of Na2CO3 extract was acidified with dil. HCl in boiling tube. Acidity was checked with litmus. It was kept in a hot water bath for about 3 minutes and added 3 drops of BaCl2	When the extract was acidified with HCl, it turned into brownish red colour. White colour precipitate was formed.

NO₂^-

Procedure	Observation
1ml of Na2CO3 extract was heated with dil. H2SO4 in boiling tube. The evolved gas was checked with starch.iodide paper.	With H2SO4 the extract turned into reddish brown colour. Brown fume was evolved when heating. It turned the starch-iodide paper into blue colour.

NO₃^-

Procedure	Observation
1ml of Na2CO3 extract was heated with 100mg Sulphamic acid in a boiling tube. Later dil.NaOH was added and heated until the evolution of NH3 is ceased. It was again checked with Devarda’s alloy.	In the presence of Sulphamic acid the solution turned into brownish red. Pungent smelling brownish colour gas was formed and the it continued for awhile in Devarda’s alloy.

PO₄^3-

Procedure	Observation
1ml of Na2CO3 extract, 1ml of dil. HNO3 and 10ml ammonium molybdate was heated gently in a boiling tube.	With HNO3 the extract turned into brownish red colour. Later a yellow colour precipitate was obtained.

What’s the purpose of preparing Na₂CO₃ extract?

It gives an expedient way of bringing all the anions of the sample into solution. Otherwise they might be insoluble and couldn’t carry out the experiment properly. Also it prevents the cation in interfering.

What is the importance of Na₂CO₃ extract to be clear and colourless?

This provides a better setting to observe formations of precipitates, colour changes which take place during the experiment.

Is the Na₂CO₃ extract basic or acidic?

It is slightly basic.

Analysis of amino acids by paper chromatography- Theory

Chromatography is a technique for analyzing or separating mixtures of substances into their components. There are various forms of chromatography techniques. Generally all of these forms involve two distinct phases; the Stationary phase and the mobile phase.
In paper chromatography the stationary phase:- Absorbent paper, Mobile phase:- A suitable liquid or a mixture of solvents.
Mobile phase flows through the stationary phase and carries the components of the mixture with it.
The stationary phase retards the passage of components of the sample.
When components pass through the system at different rates they become separated in time.
This depend on their solubility in the solvent and how well the chromatography paper absorbs.
More soluble the component is in the solvent and the less it absorb into the paper, the faster it would move with the solvent on the paper and hence the spot appears further up the paper.
There are three types of paper chromatography.

• Ascending paper chromatography
• Descending chromatography
• 2-D paper chromatography

In paper chromatography cellulose in the form of paper sheets makes an identical support medium as it has the ability to absorb water molecules between cellulose fibers and forms a stationary hydropholic phase.

In analysis of amino acids by paper chromatography, the location of the amino acids can be determined by spraying the paper with Ninhydrin. The Ninhydrin forms a blue violet complex with an amino acid except for proline/hydroxy proline which gives a yellow color complex.