The drying behaviour of green dasheen leaves (Colocasia esculenta Linn.) as affected by temperature and blanching treatments

Sankat Clement K., . and Maharaj Vashti, . The drying behaviour of green dasheen leaves (Colocasia esculenta Linn.) as affected by temperature and blanching treatments. pp. 138-144. ISSN 1505-5337

The drying bahaviour and quality of dasheen leaves at air temperatures of 40-70 degree C under forced convection conditions were studied in an attempt to develop a dehydrated product from this leafy vegetable. The effects of various pre-treatments on the drying behaviour of the leaves at 60 degree C were also investigated viz: steam and water blanching and blanching in 0.06 percent magnesium carbonate solution at near boiling prior to immersion in a mixed chemical bath consisting mainly of 20 percent sucrose. Irrespective of drying air temperature and pre-drying treatment drying was characterized by a single falling rate period of drying. Drying rate increased with drying air temperature the drying rate constant K being 0.964 hr (-1) at 40 degree C and 3.094 hr (-1) at 70 degree C. Drying of unblanched dasheen leaves at 40-70 degree C resulted in a colour change from green typical of the fresh vegetable to olive-green with browning. Blanching in water or alkali infusion prior to drying whilst reducing the rate of moisture removal resulted in attractive dehydrated products green with no browning.

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Abstract

The drying bahaviour and quality of dasheen leaves at air temperatures of 40-70 degree C under forced convection conditions were studied in an attempt to develop a dehydrated product from this leafy vegetable. The effects of various pre-treatments on the drying behaviour of the leaves at 60 degree C were also investigated viz: steam and water blanching and blanching in 0.06 percent magnesium carbonate solution at near boiling prior to immersion in a mixed chemical bath consisting mainly of 20 percent sucrose. Irrespective of drying air temperature and pre-drying treatment drying was characterized by a single falling rate period of drying. Drying rate increased with drying air temperature the drying rate constant K being 0.964 hr (-1) at 40 degree C and 3.094 hr (-1) at 70 degree C. Drying of unblanched dasheen leaves at 40-70 degree C resulted in a colour change from green typical of the fresh vegetable to olive-green with browning. Blanching in water or alkali infusion prior to drying whilst reducing the rate of moisture removal resulted in attractive dehydrated products green with no browning.

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Item Type:	Article
Additional Information:	Summary (En)
AGROVOC Term:	COLOCASIA ESCULENTA
AGROVOC Term:	DRYING
AGROVOC Term:	TEMPERATURE
AGROVOC Term:	BLANCHING
AGROVOC Term:	MOISTURE CONTENT
AGROVOC Term:	QUALITY
AGROVOC Term:	USA
AGROVOC Term:	CANADA
AGROVOC Term:	EUROPE
AGROVOC Term:	TRINIDAD AND TOBAGO
Depositing User:	Ms. Norfaezah Khomsan
Last Modified:	24 Apr 2025 05:52
URI:	http://webagris.upm.edu.my/id/eprint/17461

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