73C-14 |
Drying rates and browning kinetics of dried apricots (Prunus armenica L.) blanched and treated with different solutions. |
N. DEMIR, A. Z. Odabasi, and M. O. Balaban. Food Science and Human Nutrition Department, University of Florida, P.O. Box 110370, Gainesville, FL 32611 Enzymatic browning in fruits and vegetables is controlled by blanching and treatment with different chemicals. Conventional measurement requires sample preparation, and long experimental times. Color machine vision analysis is a fast, non-destructive alternative. The objective of this study was to calculate kinetic of color changes of apricots dipped in different solutions and air dried with a computer vision system, and obtain the drying rate data. Fresh apricots were dipped in various solutions for 1.5 hr (200ppm Sodium Meta Bisulfate (SMB), 1% Ascorbic acid (AA), 100 ppm 4-Hexylresorcinol (4HR), 0.75% citric acid (CA), combinations of water-honey (1:1), water-sugar (1:1); pure water (control)). Some samples were blanched for 2 min at 65 ºC and cooled, dipped in sugar solution (1:1) for 1.5 hr; others were kept as controls. All samples were air-dried (40% RH, 56ºC) for 10 hr. Weight changes during drying were monitored. RGB colors from images captured before and after dipping, and during drying were measured. First order rate constants of dark and light color changes were calculated. Dipping in honey and sugar solutions resulted in more moist products after drying, retaining 25-30% of the original weight, compared to 15% for other solutions. Average L a b values, and % color changes showed that the best color preservation was obtained with blanching and sugar (1:1) dip followed by blanching only. First order kinetics of reduction in lighter colors and increase in darker colors are given. Color blocks 498 (R=240,G=208,B=80) + 490 (R=240,G=176,B=80) for light colors, and 346 (R=176,G=112, B=80) + 274 (R=144,G=80, B=80) for dark colors were chosen. This method can rapidly and quantitatively determine browning rates. The disappearance of lighter colors as well as the formation of darker colors can be quantified in non-uniform colors and surfaces.
Session 73C, Food Engineering: Transport Processes and Kinetics
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