Rehydration of dehydrated foods

Krokida, MK; Philippopoulos, C

dc.contributor.author	Krokida, MK	en
dc.contributor.author	Philippopoulos, C	en
dc.date.accessioned	2014-03-01T01:23:01Z
dc.date.available	2014-03-01T01:23:01Z
dc.date.issued	2005	en
dc.identifier.issn	0737-3937	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/16770
dc.subject	Apparent density	en
dc.subject	Compression tests	en
dc.subject	Flavor	en
dc.subject	Fruits	en
dc.subject	Porosity	en
dc.subject	Rehydration kinetics	en
dc.subject	Structural properties	en
dc.subject	Texture	en
dc.subject	Vegetables	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.classification	Engineering, Mechanical	en
dc.subject.other	Dehydration	en
dc.subject.other	Flavors	en
dc.subject.other	Hysteresis	en
dc.subject.other	Moisture	en
dc.subject.other	Porosity	en
dc.subject.other	Shrinkage	en
dc.subject.other	Thermodynamic properties	en
dc.subject.other	Viscoelasticity	en
dc.subject.other	Viscosity	en
dc.subject.other	Dehydrated foods	en
dc.subject.other	Rehydration	en
dc.subject.other	Rehydration kinetics	en
dc.subject.other	Food products	en
dc.subject.other	dehydration	en
dc.subject.other	food industry	en
dc.title	Rehydration of dehydrated foods	en
heal.type	journalArticle	en
heal.identifier.primary	10.1081/DRT-200054201	en
heal.identifier.secondary	http://dx.doi.org/10.1081/DRT-200054201	en
heal.language	English	en
heal.publicationDate	2005	en
heal.abstract	Dehydrated products readily take up moisture when immersed in a liquid medium, leading to significant changes in their thermophysical properties. The rehydration kinetics, the structural properties (apparent density, true density, specific volume and internal porosity), the viscoelastic behavior (compression tests), and the flavor losses were investigated during rehydration of various fruits and vegetables. The effect of temperature on the above properties was also investigated for some fruits and vegetables dehydrated by different drying methods (convective, vacuum, freeze, and osmotic drying). The results showed that the water temperature influences the rehydration kinetics and the equilibrium moisture content of the rehydrated. The structural properties of rehydrated foods appear to show a hysteresis compared to those measured during dehydration processes. The shrinkage that takes place during dehydration prevents rehydration and produces products with lower apparent density and higher porosity. Structural damages that occur during drying seem to affect also the viscoelastic behavior of the rehydrated foods and the hysteresis phenomenon is also observed at the textural properties, with a degree varying between the different drying methods. More specifically, freeze-dried materials present the highest hysteresis after rehydration, losing their elasticity and becoming more viscous. Osmotic pretreatment seems to help freeze-dried materials to keep their elastic nature probably due to solids gain. Air-and vacuum-dried materials showed the smallest hysteresis tense, keeping their viscoelastic characteristics during rehydration close to those of dried materials. Flavor losses seem to have lower rates during rehydration comparing to those observed during drying. The maximum retention of flavor has been observed in the rehydrated products after freeze-drying, and flavor levels are close to those observed for fresh boiled foods. Copyright © 2005 Taylor & Francis, Inc.	en
heal.publisher	TAYLOR & FRANCIS INC	en
heal.journalName	Drying Technology	en
dc.identifier.doi	10.1081/DRT-200054201	en
dc.identifier.isi	ISI:000228668700007	en
dc.identifier.volume	23	en
dc.identifier.issue	4	en
dc.identifier.spage	799	en
dc.identifier.epage	830	en