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IMAGE ANALYSIS AND DYNAMIC MODELING OF THIN‐LAYER DRYING OF OSMOTICALLY DEHYDRATED PUMPKIN
Author(s) -
ZENOOZIAN M. SHAFAFI,
FENG H.,
RAZAVI S.M.A.,
SHAHIDI F.,
POURREZA H.R.
Publication year - 2008
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.2007.00167.x
Subject(s) - osmotic dehydration , sorbitol , sucrose , chemistry , dehydration , coefficient of determination , lightness , food science , chromatography , mathematics , biochemistry , statistics , physics , optics
This study was conducted to investigate the effect of osmotic dehydration as a pretreatment on hot‐air drying kinetics of pumpkin, to evaluate the best model for hot‐air drying of pumpkin and to apply a computer vision system to study the color changes during drying. Pumpkin cubes were treated in 50% w/w sorbitol or sucrose solutions at 50C for up to 6 h, followed by hot‐air drying at 60C and air velocity of 1 m/s. Drying data were fitted to 11 drying kinetic models. The goodness of fit was determined using the coefficient of determination ( R 2 ), reduced chi square (χ 2 ), root mean square error ( RMSE ) and percent mean relative deviation modulus ( E %). Hot‐air dried samples pretreated with sorbitol had an improved lightness (higher L * values) compared to the hot‐air drying while that pretreated with sucrose exhibited lower L * values . The total color changes ( ΔE * values) increased during drying in a sequence of ΔE * sucrose solution < ΔE * sorbitol solution < ΔE * sucrose+hot air & < ΔE * sorbitol+hot air .PRACTICAL APPLICATIONS The combined treatment of pumpkins using osmotic dehydration followed by hot‐air drying may provide a practical method for the preservation of pumpkin and the production of dehydrated pumpkin products.