Introduction:
Curing is a process in tobacco by which harvested leaves are made ready for marketing. The sole object of curing is dry the green leaf to get final product required colour, texture and aroma.
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Curing:
Curing is a process of drying, decomposition of chlorophyll till green colour disappear, hydrolysis of starch into sugar and fermentation of sugar.
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Flue curing is an improved method of curing, in which drying of leaves under artificial condition without contact of green leaf with smoke.
Feature —
i. Drying of leaf under controlled conditions.
ii. Starch get converted into sugar.
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iii. Green tobacco becomes bright, aromatic and fine textured.
Variety Suitable for Flue Curing:
i. Virginia Gold
ii. Harison Special
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Production Technique of Flue Cured Tobacco:
1. Raised with low nitrogen supply
2. Harvest at an advanced stage when rich in starch, low in Nicotine content.
3. The leaves are harvested by priming 3-4 leaves at a time.
Method of Flue Curing:
Harvested green leaves are strung on sticks
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Stacked into a specially constructed flue cured pan.
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Artificial heating with gradual increase in temperature till leaves dry.
Stages in Flue Curing:
1. Yellowing of leaf
2. Fixing of colour
3. Drying of leaf
1. Yellowing of Leaf:
i. Slow heating is to give optimum humidity.
ii. Retain Moisture
iii. At end, leaf attain lescion yellow colour
iv. Starch converted to sugar
v. completed within 1 to l 1/2 day
2. Fixing of Colour:
i. Increase temperature gradually with decrease in humidity.
ii. Completed within 1 to 1 1/2 day.
3. Drying of Leaf:
i. Drying the midrib of leaf
ii. Temperature of pan increase @5°C for 1 hr. till reaches to 170-180°F for one day.
iii. After drying leaves leaf in pan overnight with ventilation.