Osmotic dehydration of tomato in ternary solutions: Influence of process variables on mass transfer kinetics and an evaluation of the retention of carotenoids

• Published in: Journal of food engineering 2007-10, Vol.82 (4), p.509-517
• Main Authors: Tonon, Renata V., Baroni, Alessandra F., Hubinger, Míriam D.
• Format: Article
• Language: English
• Subjects: Agitation; Agitation speed; aqueous solutions; Biological and medical sciences; Carotenoids; Coefficients; Dehydration; diffusivity; drying; Empirical equations; Food engineering; Food industries; food nutrient losses; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; General aspects; kinetics; mass flow; Mass transfer; Mathematical models; nutritive value; Osmotic dehydration; osmotic treatment; salt content; shrinkage; Sodium chloride; Sucrose; sugar content; Tomato; tomatoes; viscosity; water content
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2007.03.008

The objective of this work was to study the influence of temperature (20–40 °C), solution composition (0%salt/65%sucrose–10%salt/55%sucrose) and agitation speed (0–1000 rpm) on the mass transfer kinetics of osmotically dehydrated tomato halves. The mass transfer kinetics were modeled using a first-order kinetic equation, by way of an empirical parameter ( k) representing an overall mass transfer coefficient. Carotenoid retention was analyzed after 6 h of processing. The results showed that the overall mass transfer coefficients for water, NaCl and sucrose were positively influenced by the temperature and by an increasing solution salt content. The agitation speed had a significant influence on water loss, indicating that in this case, the mass transfer was not only governed by an internal mechanism, as appeared to be the case with the solutes. Osmotic dehydration apparently had no effect on the carotenoid content of the processed products, and can be considered to be an efficient method, allowing for water removal without changing the nutritive value.