PHG 413

LAB# 4

food coloring agent

King Saud UniversityPharmacy Collage Pharmacognosy Department

Definition:

Substance Colors Sources Used in

Anthocyanins

orange-red

berries, grapes, apples,

roses, red cabbage, sweet

potato

candy, fruit beverages, ice

cream, yoghurt , jams

Caramel beige to brown

heated sugars

baked goods, gravies, vinegars,

syrups, colas, sauces

Betacyanins

red red beets, cactus fruit

candy, yogurt, ice cream, salad dressing, cake

mixes

Naturally occurring colorants

Naturally occurring colorants cont.

Substance Colors Sources Used in

Carmine red cochineal insects

candy, dairy products, drinks,

fruit fillings

Carotenoids

(precurser of vit.A )

yellow to orange to

red

saffron, tomatoes,

paprika, corn, butter,red

salmon, marigolds,

marine algae, carrots

meat products, cheese, butter,

spice mixes, salad dressings

Chlorophylls

green to olive green

green plant leaves

dehydrated spinach

Naturally occurring colorants cont.

Substance Colors Sources Used in

Riboflavin(vit.B2 )

yellow vegetable leaves, milk, eggs, organ meats, malt

flour, bread, pastries, cereals, dietary products

curcuminyellow Curcuma longa rhizome

pickles, mustard, spices, margarines, ice cream, cheese, baked goods, soups, cooking oil, salad dressings

Examples of natural food coloring agent:

1) Turmeric:

• Name: turmeric

• Origin: dried rhizomes of curcuma longa

• Family: zingiberaceae (ginger family)

• Odour: characteristic aromatic

• Taste; charactristic aromatic

• Chemical test: mixture equal part of ( alc. +H2SO4)

sprinke small quantity of pd. The particle turn red & the red colour is gradually flows out into the reagent

• Uses: condiment, colouring agent, stimulant &carminative

• Active constituent:

1- 1-5% orange yellow volatile oil

2- 0.3% of yellow crystalline dye (curcumin)

3- 30-50% starch

4- resin

1 -turmeric:

TLC detection of turmeric:

1 -weigh 0.2 g of turmeric pd.& put in 1ml EtOH.

2-leave for 30 min ,stir then filtrate 3 -determine the starting line 1cm from the edge

of a plate then put a small spot of your sample .

4 -then immerse the plate in jar which contain solvents

) solvent system:ethanol: chloroform:ethanol:acetic acid(94+5+1)

5 -allow the system to develop over the silica gel plate.6 -determine solvent front line

7 -use UV to detect spot, then move the plate over ammonia vapour

8- calculate RF value

TLC detection of turmeric : cont.

1cm

Spot of authentic turmeric

Solvent front

Dis

t.tr

av

ell

by

sub

.y

Dis

t. T

rave

ll b

y s

olv

.x

curcumin

desmethoxy curcumin

bisdesmethoxy curcumin

Distance traveled by the substance (Y)

Distance traveled by the solvent (X)

Rate flow

Adulterant Simple Method for detection

Chalk powder or yellow soap stone powder

Take a small quantity of turmeric powder in a test tube containing small quantity of water. Add a few drops of concentrated Hydrochloric acid, effervescence (give off bubbles) will indicate the presence of chalk or yellow soap stone powder

Quick test to detect turmeric adultration

Examples of natural food coloring agent:

2) Saffron:

• Name: Saffron

• Origin: dried stigma of Crocus sativus

• Family: iridaceae

• Odour: strong characteristic

• Chemical test: *Saffron +conc.H2SO4 deep blue

which changes to violet & finally to wine red (purplish red)

*saffron + H2O yellow

• Uses: colouring agent & antispasmodic

Cont.

2) Saffron:

• Active constituent:

1- glycoside coloring matters (Crocin)

2- colourless glycoside (picrocrocin)

3- volatile oil & wax

Cont.

2) Saffron:

• Microscopical examination:

A- spherical smooth exine pollen grain

B- epidermis of style

c-Parenchymal cells d-vessels

Cont.

Some forms of saffron adultration:

1-to increase the wt. of saffron & decrease its price, it is mix with sand, grains of lead, red dye silk fiber.

*can be detect by: scatter the saffron loosely over a sheet of white paper,when the sand or grains of lead fall out .

2- to give saffron flexibility & appearance of freshness, as well as to augment its weight, it is sometimes damped or oiled. * can be detect by: to detect either water or oil ,small portion of saffron should be subjected to pressure between folds of white paper, if this

become either moistened or greased the adultration is obvious.

saffron substitutes:

Cont.

1 -intermixing saffron with the petals of some plant usually safflower (bastard saffron)

*can be detect by: if rubbed with the moistened finger on paper *slight yellow mark only safflower *intense orange-yellow stain saffron

Examples of natural food coloring agent:

3) Safflower:

• Name: safflower

• Origin: tubular florets of Carthamus tinctorius

• Family: Asteracae

• Odour: slightly aromatic

• Chemical test: with alc.H2SO4 orange

• Uses: colouring agent & as anti-inflammatory.

Cont.

3) Safflower:

• Active constituent:

1- red coloring substance ( carthamin)

2- yellow coloring substance safflower yellow

3- fixed oil & mucilage

Cont.

3) Safflower:

• Microscopical examination:

A- spherical spiny pollen grain

Cont.

practical work for today:

1 -TLC for turmeric pd.

2- chemical test to detect unknown turmeric

pd. is adultrated or not.

3-chemical test (turmeric &safflower) 4-

spots.