A study of diffusion of dyes in model foods using a visual method

► The diffusion of dyes in gels was visualised in situ for 10min. ► Agar and alginate gels were used with rhodamine 6G and methylene blue dyes. ► Experiments were performed at 30, 50, and 70°C and 0, 167, 333, 500, 667Vm−1. ► Limitations of Fickian analysis led to the penetration model for data anal...

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Bibliographic Details
Published inJournal of food engineering Vol. 110; no. 3; pp. 441 - 447
Main Authors Samprovalaki, K., Robbins, P.T., Fryer, P.J.
Format Journal Article
LanguageEnglish
Published Oxford Elsevier Ltd 01.06.2012
Elsevier
Subjects
Biological and medical sciences
Charge
Diffusion
Diffusion effects
Dyes
Electric fields
Food engineering
Food industries
Foods
Fundamental and applied biological sciences. Psychology
Gels
General aspects
Image analysis
Mass transfer
Ohmic heating
Penetration
Image analysis
Ohmic heating
Gels
Diffusion
Models
Method
Food
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Summary:► The diffusion of dyes in gels was visualised in situ for 10min. ► Agar and alginate gels were used with rhodamine 6G and methylene blue dyes. ► Experiments were performed at 30, 50, and 70°C and 0, 167, 333, 500, 667Vm−1. ► Limitations of Fickian analysis led to the penetration model for data analysis. ► Gel, gel/salt concentration, dye charge/mass, electric field effects were examined. Many food processing operations involve mass transfer. The application of electric fields can influence the mass transfer properties of foods. A major limitation of infusion studies is the lack of successful measurement techniques to quantify the depth of penetration and localisation of infused material. Diffusion of two dyes (rhodamine 6G and methylene blue) in agar and alginate gels was visualised insitu for 10min. The experiments were performed at three temperatures (30, 50, and 70°C) and four voltage gradients (167, 333, 500, 667Vm−1) plus a control (0Vm−1). The effect of hydrocolloid concentration and electrical conductivity on diffusion and response to the electric field were tested. The limitations of Fickian analysis led to a new method of data analysis, the penetration model. The effect of the type of gel and the diffusing molecule charge and mass on the combined diffusion and electric field process is discussed.
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ISSN:0260-8774
1873-5770
DOI:10.1016/j.jfoodeng.2011.12.023