Chapter 8
Processing and value addition in Ornamental crops
Processing in Ornamental Crops
When conditions are not suitable for storage or immediate marketing of freshproduce, many flower crops can be processed using simple technologies.
There are different methods to extract essential oil from flowers
1. Enfleurage or Cold fatextraction
2. Maceration or hot fatextraction
3. Solvent extraction (Petroleum ether andbenzene)
4. Super-critical fluid extraction
1. Enfleurage or Cold fatextraction
Enfleurage is one of the oldest methods of extracting essential oils and is rarely used
thesedaysbecauseofitshighcost. It involves placing the flower petals on a layer of glass that is
first spread with a thin layer of fat called "chassis". The volatile oil diffuses into the fat,
then the fat is collected and the oil is extracted from the fat usingalcohol.
thesedaysbecauseofitshighcost. It involves placing the flower petals on a layer of glass that is
first spread with a thin layer of fat called "chassis". The volatile oil diffuses into the fat,
then the fat is collected and the oil is extracted from the fat usingalcohol.
Once the alcohol evaporates what is left behind is called the absolute. As
youcanimagine,thisisaverytimeconsumingprocess,butitwastheonly way to
extract delicate flowers like Jasmine for a very longtime!
Jasmine and tuberose give their greatest yield of flower oil upon extraction
with cold fat (enfleurage) because their physiological activities continue for
24 hr. and longer after harvesting. During this period, the fat on the chassis
absorbs the perfume emitted by these flowers.
2. Maceration or hot fatextraction
The flowers are extracted by immersion in hot fat. In other words, the same batch of
hot fat is systematically treated with several batches of fresh flowers until the fat
becomes quite saturated with flower perfume. The exhausted flowers are removed
and the fragrant fat, called Pomade d'Orange, Pomade de Rose, etc., is sold as such,
or the pomade may be treated further by washing it with strong alcohol, exactly as
with jasmine or tuberose pomades, obtained by cold enfleurage. The alcoholic
extraits (Extrait d 'Orange, Extrait de Rose, etc.) may be marketed as such, or they are
concentrated in vacuo, giving thereby the corresponding absolutes ofpomade.
3. Solvent extraction
Solvent extraction, also called liquid-liquid extraction or partitioning, is
a procedure used to separate compounds based on their solubility in
two immiscible liquids, usually water and an organic solvent.
Whenever an oil with natural flavor is required, direct extraction with
solvents such as petroleum ether or benzene is practiced.
The solvent is first allowed to run slowly through the flowers, washing out the
essential oils and waxes. The solvent is then allowed to evaporate under
vacuum, leaving behind a semi solid residue of essential oils and waxes in the
retort. The mass is then treated with alcohol to dissolve out the essential oil,
the waxes being removed by filtration or precipitated out by freezing. Later, the
alcohol can be evaporated to isolate the floral absolute.
4. Super-critical fluid extraction
CO2 is the most popular solvent used in Super-critical fluid extraction.It
hasbeenreportedthataromaofextractsusingsupercriticalCO2better
resemble the aroma of the natural plant then do steam distilled extracts.
Value Addition of Flowers through Dry Flower Technology
Dry flowers preserve special gift bouquets, creating a beautiful long-lastingarrangement for indoors. They add value to create decorative centerpieces for home with the
benefit that they require very little maintenance that too in the days of flower scarcity. Dry
flowers have good demand both in Indian and international markets. From India it is being
exportedtocountrieslikeUSA,JapanandEurope.Indiastandsfirstindryflowerexportowing to the
availability of variety of plants. Dry flowers do not mean only flower parts, but also includes
dried shoots, seeds and barks. Export of dried flowers and plants from India is about Rs 100
crore per year. The industry exports 500 varieties of flowers to 20 countries. They are widely
used to make handmade paper, lampshades, candle holders, jute bags, photo frames, boxes,
books, wall quilts, topiary, cards and several gifts. The use of dry flowers in making of these
products enhances the appearance and beauty of theseproducts.
Tips of Picking and Drying Dried Flowers
Since drying will emphasize imperfections, hence quality flowers should
be chosen for drying.
Blue, orange and pink flowers retain best color on drying.
Pickingshouldbedonewhenthedewevaporatesfromtheflowers.
Picking of flower in dry weather isbest.
Most flowers should be picked when they are at their peak and are
starting to open up. Picked flowers should be immersed in a bucket of
lukewarm water in a cool, dry place.
Harvested stems should be grouped into bunch using rubber band.
Dried flowers should be kept away from sunlight.
Excessive heat, humidity and dust must be avoided to prevent colour fading.
Dried flowers should be cleaned regularly by blowing off the dust, using
a hair dryer on the no-heat setting, or using canned air.
No matter which method has been used to dry the flowers, they should
then be sprayed with an aerosol sealer to help hold their color and
minimise or prevent shattering.
Avoid using anything sticky, like hairspray, which will attract dust.
Materials and Methods of preserving flowers
Generally, flowers are dried by three basic techniques that is hanging, pressing and via
use of desiccants.
•To hang or air-dry flowers, one needs floral wire, rubber bands and string.
Topressflowers,oneneedsastackofheavybooksoraflowerpressandwaxpaper
or blotting paper.
To dry flowers using a desiccant, one needs silica gel, borax orsand.
There are many ways to dry or preserve plant materials. Air drying is the most
common and easiest, flowers dried in silica gel keep their colour and form well
and glycerine preservation is recommended for foliage andberries
There are at least five ways to preserve the beauty of garden flowers to
brighten up the dull days of winter.
Many blossoms, such as strawflowers (Helichrysum bracteatum), most
daisies, celosia, baby's-breath (Gypsophila elegans), statice (Limonium
sinuatum), and the annual ornamental grasses, can be air-dried in a
number of ways. Whatever the species, first remove all the leaves, then
find a room or area that is reasonably dark but has plenty of ventilation.
Flowers with stiff stems, such as bells-of-Ireland (Moluccella laevis), can simply be
placedinaglassjarorvaseuntiltheyaredry.Thosethatperchonfloppystemscan
be hung upside down in loose bundles from individual nails or hooks,or
a number of bunches can be attached to wire clotheshangers.
One can staple a big square of chicken wire to a wooden frame, and
suspend the flowers with the stems hanging through the holes.
Often when a vase of flowers is forgotten for weeks, the owner will
suddenly find the water has long gone but the flowers have dried
naturally. This method works especially well for drying leaves.
Another good method for drying flowers employs the fine white sand
sold at building and home centers and used for filling children's sandboxes.
First find a strong plastic or wooden box that can withstand the weight of the
sand and then spread an inch-deep layer of sand on the bottom. Carefully
place the flowers on that base and slowly sprinkle dry sand over and about the
flowers until they are completely covered. Do not cover the container. Check
after three weeks have passed to see if the flowers aredry.
Dry Flower Techniques:
Broadly flower drying comprises of various drying
techniques and dyeing process.
techniques and dyeing process.
A. Drying
AirDrying
Airdrying is done in a warm, dry place with adequate air circulation. Drying naturally in the air
produces some of the best results. It is the preferred method for large-scale drying
operations.Most plants dry best when tied in bunches and hung upside down by removing all
leaves. Six to ten stems ends are tied together about two inches from the stem ends with the
help of a rubber band. Plants are thoroughly dried in three weeks when the stems snap easily.
Chinese lanterns, baby's wreath, poppy seed-heads and globe thistles dry better right-side up.
Simply plants are placed in a wide-mouth jar or coffee can to dry. Foliage and grasses can be
air dried by laying them on newspaper or cardboard.Globe Amaranth, strawflowers and
immortelle have weak stems. These stems should be removed and replaced with florist's wire
before the flower is dried. Stem of plant is cut 1/2-inch below the flower and floral wire is
inserted up through the remaining stem and through out the center of the flower. A hook is
made at the top of the wire and is pulled back down into the flower. The stem around the wire
shrinks and dry up tightly. Once the flower is dry, floral stem is wrapped with the help of tape
andwire.Tostrengthendriedflowers,clearlacquer,hairsprayorclearcraftsprayissprayed.
Water Drying
Although it sounds improbable, some flowers can be dried well in water. One needs to
strip the leaves and put the stems in about 2 inches of water and leave to rest in a dry, dark
and warm location. The water is then absorbed by the flowers and evaporated. Yarrow,
hydrangeas, bells of Ireland, ageratums, alliums, acacia, celosia and gypsophila take well to
water drying. Because they are top-heavy, it's best to dry fennel, dill, Queen-Anne's-lace and
edelweiss by placing the stems through the holes in 1/4-inch hardware cloth. The hardware
cloth will support the heavy heads, while the stems hang loosely below.
produces some of the best results. It is the preferred method for large-scale drying
operations.Most plants dry best when tied in bunches and hung upside down by removing all
leaves. Six to ten stems ends are tied together about two inches from the stem ends with the
help of a rubber band. Plants are thoroughly dried in three weeks when the stems snap easily.
Chinese lanterns, baby's wreath, poppy seed-heads and globe thistles dry better right-side up.
Simply plants are placed in a wide-mouth jar or coffee can to dry. Foliage and grasses can be
air dried by laying them on newspaper or cardboard.Globe Amaranth, strawflowers and
immortelle have weak stems. These stems should be removed and replaced with florist's wire
before the flower is dried. Stem of plant is cut 1/2-inch below the flower and floral wire is
inserted up through the remaining stem and through out the center of the flower. A hook is
made at the top of the wire and is pulled back down into the flower. The stem around the wire
shrinks and dry up tightly. Once the flower is dry, floral stem is wrapped with the help of tape
andwire.Tostrengthendriedflowers,clearlacquer,hairsprayorclearcraftsprayissprayed.
Water Drying
Although it sounds improbable, some flowers can be dried well in water. One needs to
strip the leaves and put the stems in about 2 inches of water and leave to rest in a dry, dark
and warm location. The water is then absorbed by the flowers and evaporated. Yarrow,
hydrangeas, bells of Ireland, ageratums, alliums, acacia, celosia and gypsophila take well to
water drying. Because they are top-heavy, it's best to dry fennel, dill, Queen-Anne's-lace and
edelweiss by placing the stems through the holes in 1/4-inch hardware cloth. The hardware
cloth will support the heavy heads, while the stems hang loosely below.
Microwave Drying
Flowers can also be dried in a microwave oven. In this case, bury the flowers in a
desiccant as outlined above, but do not cover. Place the container into the microwave and
'cook' at a low-medium setting (the 'defrost' setting on many ovens) for about 2 ½ minutes, or,
if you have a microwaveable thermometer that you can read from outside the oven, until the
silica near the buried flower reaches approximately 160° F. When the container of dried
flowers is removed from the microwave oven, place a lid (slightly vented) on it, and allow it to
sitforabout24hoursbeforecarefullyuncoveringtheflowers.Sinceovens,dryingagents,and flowers
all vary considerably, it's best to experiment with this technique before committing 'good'
flowers to the process. Usually foliage is suitable for microwavedrying.
Desiccant Drying
Perhaps the best way to dry flowers is by using a desiccant in which flowers are buried
until they have dried. By using this method, the shapes and colors of more
dimensional flowers like roses, carnations, marigolds, lilies, and dahlias can be
preservedinthedriedstate.Old-fashioned,homemixtures,suchasboraxandwhite
cornmeal(2:1)orboraxandsand(2:1)maybeused.Butthebestandfastestwayisto use
silica gel (actually a dry, granular material), which has the capacity to absorb large
quantities of moisture and can quickly dehydrate freshflowers.
Silica Gel Drying
Flowers dried in desiccants retain best color and shape. Silica desiccants are most
popular, and can be purchased at hobby and craft stores. Follow the package directions
for best results. In Silica Gel multipetalled flowers, such as dahlias, zinnias and daisies,
dry best in silica gel (found at craft and hobby stores). Place flower heads face up on a 1-
inch bed of silica gel crystals in an airtight container. Also, gently shake crystals over
flowers, covering completely. Seal container. Use a container that can be tightly
sealed so that the desiccant does not absorb any moisture form the air rather than
from the flowers. Most flowers dried in this manner are ready in about a week. Silica
gel can be re-used simply by drying again the product in a warm oven. Leave for two
days to one week, checking often to avoid overdrying (flowers will become brittle).
Using Silica or Silica gel, we can improve the quality of flowers and it makes the
flowers intact. Silica gel is the best preservative for keeping flowers in their natural
form while they dry. It will take about 2 minutes to dry flowers in half a pound of silica
gel on a setting of 200 - 300 watts. Drying with desiccants can produce some stunning
results when it works. The process is however, a little unpredictable. Silica is the most
popular desiccant used, although you can try borax mixtures too. Dry out the
desiccant in an oven first and then prepare it in a shallow container which can be
made airtight. Compact-headed flowers can be dried face up with their stem wired in
position. Flowers that press well are California poppy, Chrysanthemum, Clematis,
Columbine, Coneflower, Crocus, marigold, tulip, larkspur andDahlia.
Sand Drying
With sand drying, the flowers are either laid in an inch bed of sand with space
scooped out so that they rest snugly, or in the case of compact-headed blooms like
zinnias, put them head first into the sand with wire supporting the stem. Cover only the
petals and do not submerge the flower. Place the box in a well ventilated room with some
gentle warmth. Plants that dry well with dessicant drying method are sunflowers, roses,
yarrow, larkspur, peony, lavender, delphinium, statice, and anemone.
Sun Drying
Sun drying is the easy and cheap method. But during rainy days we can’t dry
flowers in this method. The flower bunches are hanged upside down in ropes or in
bamboo splits No chemicals are used. Good aeration is must. Chances of fungal
attack are very high in this method. Usually marigold, poppy, Zinnia,
Chrysanthemum, Acroclinum, Globe amaranthus can be dried via this method.
Freeze Drying
It is an improved method over sun drying. Freeze drying equipments are
costlier. But the quality of the dried flower is very high and fetches good
price. Roses and pansy are dried through freeze drying.
Oven Drying
Drying flowers in a warm oven uses much the same technique as drying
them in a microwave.
To dry in an oven use a very low temperature (100 degrees or less) and dry for
several hours. The oven must be fan assisted; otherwise too much moisture will
be created. Marigolds, zinnias, cornflowers, lupins and chrysanthemums can be
dried this way. Thick petal flowers like hyacinth and magnolias are unsuitable for
microwave drying. While picking flowers for microwaves, use them just before
they are fully open. Place the petals or flowers on an oven-proof tray, ensuring the
petals do not overlap. Set the oven to the lowest setting and place the tray in the
oven, leaving the door slightly ajar. Check the flowers regularly. Depending on the
thickness of the flowers to be dried, the time of dryingvaries.
several hours. The oven must be fan assisted; otherwise too much moisture will
be created. Marigolds, zinnias, cornflowers, lupins and chrysanthemums can be
dried this way. Thick petal flowers like hyacinth and magnolias are unsuitable for
microwave drying. While picking flowers for microwaves, use them just before
they are fully open. Place the petals or flowers on an oven-proof tray, ensuring the
petals do not overlap. Set the oven to the lowest setting and place the tray in the
oven, leaving the door slightly ajar. Check the flowers regularly. Depending on the
thickness of the flowers to be dried, the time of dryingvaries.
Press drying
This is an easy and popular way of drying flowers and is very useful for drying single
specimens. Flower is kept in between the pages of a book or newspaper and is pressed with a weight. Pressing in books however is not the most practical method for large flowers or for
many plants at a time. African violets, larkspur, pansies and ferns preserve well through this
pressing technique. For this one may also use either blotting paper or ordinary papers. Other
flowers-especially flat, so-called 'face flowers' like daisies, pansies, asters, cosmos and
zinnias - can be dried by pressing them. Fern fronds can be dried this way as well. Simply
placetheflowersbetweenseveralthicknessesofunglazedpaper,likeblotterpaper,newsprint, or an
old phone book. Position the flowers so that none are overlapping or touching. Then place a
heavy weight, such as stacks of bricks or books, evenly distributed, on top. Flowers dried in
this manner are usually ready in two to four weeks, depending on their moisture content.
There are also special devices called flower presses that do an excellent job of this. The
flattened, dried flowers can then be arranged into a floral picture in a framed shadow box and
hung on the wall or they can be 'stemmed' by using a piece of 20 gauge florist wire. Insert the
wire up through the center of the dried flower from the back side. Bend the wire into a twoinch hairpin hook at the top and gently pull the hook back down through the flower's center
untilitjustdisappears. Then cover the wire with green o brown floral tape and they're ready to arrange.
Glycerin method:
Glycerin is filled after removing the moisture from the flowers. Very high quality
products are obtained in this method. Prepare the foliage by stripping off the bottom leaves.
Use the handle of a knife to crush the stems - this will facilitate absorption of the glycerine.
Mixonepartofglycerinewithtwopartsofboilingwaterandpourtheliquidintoavaseorjar.
Stand the stems in this mixture, ensuring they are covered with 10 cm of the liquid. Place
inacool,darkplace.Itwilltakethematerialsabout2–3weekstodry.By this time, the
leaves would absorb the mixture and change slightly in colour. Check that the
water and glycerine level remains constant, topping it up if necessary. Remove
the materials from the solution, rinse them and dry with blotting paper. Glycerinedried materials last for a long time and can be wiped with a damp cloth to keep
them looking their best. Drying plant materials with glycerine keeps them more
pliable and retains their natural shape, but it does tend to cause the foliage to
change colour. Glycerine drying is recommended for leaves and berries. Leaves
from the camellia flower or from the ivy, maidenhair fern or eucalyptus tree, are all
good candidates for drying with glycerine.
Polyset polymer
By spraying polyset polymer flowers get dried. Drying time is very less in
this method. It improves the color of the finalproduct
B. Dyeing
“Procion” type colour is best for dry flowers.
Take 4 kg of dye-powder and mix with 20 litres of
water. Dilute this solution in 800 litres of hotwater.
Mix 2 litres of acetic acid
ForverysoftflowersaddMagnesiumChloridetoenhancethe
color Soak the dried flowers until they absorb thecolour.
C. Sulphuring
It is used to prevent enzymatic colour change.
Traditionallysupergranuleshavebeenburntforabout2hrsinaclosed
chamber along with dry flowers.
It is very toxic, so we have to check relevant safety instructions.
D. Bleaching
Bleached ornamental plant material provides a striking contrast when
arranged with dried or dyed flowers.
Both oxidative (hypochlorite, chlorite, and peroxide) and reductive
bleaching chemicals (sulphate and borohydride) are used for bleaching
of ornamental plants and flowers.
Sodium chlorite is an excellent bleaching agent because it is relatively
selective for lignin with out damaging fiber.
Optimum pH of 3.5- 4.5 and temp 70O C is optimum for bleaching.
E. Post harvest handling of driedflowers:
Since dry flowers are made up of cellulose materials of plant origin, it
invites a lot of insects.
Due to hygroscopic nature it allows to absorb moisture leading to
problem of mould infection.
The dried flowers are treated with a suitable biocide (insecticide and
fungicide) and are packed in water proof containers.
F. Packing
Card board boxes, thermo cool packing, poly lined or wax paper lined cartons
are normally used for packing of dry flowers