Dehydrate Water content from plant matter using approved procedures e.g. shade drying in open areas, drying on perforated surfaces, etc.

1. Drying Procedures
of
Medicinal & Aromatic plants
Dehydrate Water content from plant matter using approved procedures e.g. shade drying in open
areas, drying on perforated surfaces etc.
Ummar Atta
Ph.D Scholar, Division of Forest Products & Utilization, Faculty of
Forestry, SKUAST-K

2. Introduction
 Quality distinction was already made some 4000 years ago in ancient Egypt
between medicinal plants dried in the sun and those dried in the shade.
 At the time of Harvesting;
• Leaves- 60-90% moisture,
• Roots and rhizomes- 70-85% moisture,
• Wood 40-50% moisture and
• Seeds may contain 5-10%.

3. Drying?
• "Drying" is the phase of the post-harvest system during which the product is
rapidly dried until it reaches the "safe-moisture" level. i.e 10%

4. Purpose of Drying
• The quality of drug and consequently the earnings are
significantly influenced by the drying regime.
• Extend the shelf life,
• Conserving the fresh characteristics,
• Impede the growth of fungi and moulds,
• Reduce transportation cost,
• Capitalize storage space.

5. Steps for Drying MAPs
• Step 1: Gather MAPs. The best time to do this, is in the morning before the sun is
shining on them. It’s also best to pick the herbs before the plants start to flower.
• Step 2: Wash MAPs and pat them dry with a towel. Or, if herbs look pretty clean, shake
them gently to get rid of any residual dust or dirt. At this point, also pick off any leaves
that are yellowed, spotted, or discolored.
• Step 3: If herbs have a lower moisture content (like thyme, rosemary, oregano etc.), air-
dry them by tying them in bundles and hanging them in a place that is warm and dry with
some air circulation.
• Step 4: Store your herbs. Once your herbs are completely dry.

6. Protocols for Drying different plant
parts (NMPB)
• Underground parts: The underground
parts after harvesting must be thoroughly
washed and thereafter cut into pieces and
dried.
• Stem Bark: The bark should be split in
pieces of appropriate size to ensure
complete drying. Unless otherwise
required in specific cases, barks should be
dried in direct sunlight.
Conti..

7. Conti..
• Stem or wood: The produce should be cut in
smaller pieces to facilitate faster drying, In
case of wood, the material can be made into
small chips or shavings.
• Leaves: The leaves should not be dried in
direct sunlight, unless they have external
moisture, in which case they may initially be
dried in direct sunlight for some time and be
shifted to shade or indirect sunlight as soon
as the external moisture is wiped dry.

8. Conti..
• Fruits and seeds: Fruits may be split or cut into
small pieces to facilitate drying. Complete drying
of fruits should be ensured before they are
packed.
• Flower and floral parts: The delicate flowers and
floral parts should not be dried in direct sun
light. Flowers that are fleshy (like Madhuca
indica) may be initially dried in sun to get rid of
surface moisture and shifted to shade or indirect
sunlight afterward.

9. Different Methods of Drying MAPs
Natural or Air Drying
• Hanging herbs to dry in bunches is to
spread the herbs out on window screens.
• Hanging leaves down allows essential
oils to flow from stems to leaves.
• Tie stems in small bunches.
• Individual stems will shrink and fall.
Leaves are ready when they feel dry and
crumbly in about 1 to 2 weeks.

10.  Direct Sun-drying
• Herbs (Leaves, roots, flowers) are
distributed uniformly as a thin
layer onto the stainless steel trays/
cotton cloth or directly on ground
and dried under direct sunlight at
temperatures between 20 and 30°C
for 13 h.

11.  Shade-drying
• Herbs are arranged in a monolayer
or bunches and kept in shade for 7-
21 days; in well-ventilated, dust-
free rooms.
• Room temperature ranged from 29
to 32°C with relative humidity of
70% to 90%.

12. Drying on wooden rack Drying on round wooden rackDrying on Nylon rack

13.  Oven dried
• Ovens can also be used to dry
herbs. For quick oven drying, take
care to prevent loss of flavor, oils,
and color. Place leaves or seeds on a
cookie sheet or shallow pan not
more than 1 inch deep in an open
oven at low heat less than 180oF
(82.2oC) for about 2 to 4 hours.

14.  Solar dehydrator
• This technique relies on indirect
solar power, meaning the drying
herbs is not exposed to the sun but
instead to solar-heated air. These
dryers take advantage of the
natural process of rising hot air to
operate efficiently without any
electric fans.

15.  Infrared drying
• Another low cost drying method suitable for
employment in rural farming areas is Infrared
(IR) Drying. IR drying can be considered to be
an artificial sun-drying method which can be
sustained throughout the entire day.
• A good example of herb drying employing
simple IR technology is the dehydration of
rosemary to extract Vitamin E.
• Dehydration by convection to reduce the
moisture content from 60–70 to 8% would
require a 24-h drying cycle. It has been reported
that it is possible to achieve this 8% target in 3 h
via the IR drying system

16.  Greenhouse Dryers
• This technique can be used to do
low temperature drying of spices,
medicinal herbs etc. Utilizing a
mesh conveyor can improve
convenience and reduce hand
labor handling. The greenhouse
dryer is operated in the two
different modes of drying—
natural convection and forced
convection.

17. Thank you