Effect of ohmic pretreatment on the drying rate of grapes and adsorption isotherm of raisins

Effects of ohmic pretreatment on the drying rates of seedless red grapes and adsorption isotherms of the raisins produced were investigated. The treated grape samples were heated in a medium containing 2% citric acid to a final medium temperature of 60 o C using an alternating current at 14 V/cm fie...

Full description

Saved in:
Bibliographic Details
Published in:Drying technology 2005-01, Vol.23 (3), p.551-564
Main Authors: Salengke, S, Sastry, S.K
Format: Article
Language:English
Subjects:
drying
drying quality
drying temperature
electric current
fruit quality
fruits (food)
grapes
microwave treatment
ohmic heating
pretreatment
sorption isotherms
water activity
water content
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Effects of ohmic pretreatment on the drying rates of seedless red grapes and adsorption isotherms of the raisins produced were investigated. The treated grape samples were heated in a medium containing 2% citric acid to a final medium temperature of 60 o C using an alternating current at 14 V/cm field strength and 30 Hz, 60 Hz, and 7.5 kHz frequencies. Results of this study reveal that the drying rate of the grapes was significantly increased by the ohmic pretreatment, especially at low electrical frequencies. The effect of the ohmic pretreatment on equilibrium moisture content of the raisins produced was evident at 0.75 or higher water activities but there was no or limited effect at low to moderate water activities.
ISSN:0737-3937
1532-2300
DOI:10.1081/DRT-200054131