Viscoelastic behaviour of dehydrated products during rehydration

Krokida, MK; Kiranoudis, CT; Maroulis, ZB

dc.contributor.author	Krokida, MK	en
dc.contributor.author	Kiranoudis, CT	en
dc.contributor.author	Maroulis, ZB	en
dc.date.accessioned	2014-03-01T01:15:23Z
dc.date.available	2014-03-01T01:15:23Z
dc.date.issued	1999	en
dc.identifier.issn	0260-8774	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/13466
dc.subject	compression test	en
dc.subject	apple	en
dc.subject	banana	en
dc.subject	carrot	en
dc.subject	potato	en
dc.subject	air drying	en
dc.subject	vacuum drying	en
dc.subject	osmotic-freeze drying	en
dc.subject	freeze drying	en
dc.subject.classification	Engineering, Chemical	en
dc.subject.classification	Food Science & Technology	en
dc.subject.other	Compression testing	en
dc.subject.other	Dehydration	en
dc.subject.other	Drying	en
dc.subject.other	Food products	en
dc.subject.other	Freezing	en
dc.subject.other	Viscoelasticity	en
dc.subject.other	Osmotic freeze drying	en
dc.subject.other	Rehydration	en
dc.subject.other	Vacuum drying	en
dc.subject.other	Food processing	en
dc.title	Viscoelastic behaviour of dehydrated products during rehydration	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/S0260-8774(99)00063-1	en
heal.identifier.secondary	http://dx.doi.org/10.1016/S0260-8774(99)00063-1	en
heal.language	English	en
heal.publicationDate	1999	en
heal.abstract	Viscoelastic behaviour of dehydrated products during rehydration of apple, banana, carrot and potato was examined under uniaxial compression tests. Samples were dehydrated with four different drying methods: conventional, vacuum, freeze and osmotic-freeze drying and after that they were rehydrated in an air dryer at 50 degrees C and 80% air humidity. Compression tests were performed during rehydration for various moisture contents, ranging from 0.01 to 1.5 kg/kg dry basis. The viscoelastic behaviour of dehydrated products during rehydration were examined comparing the values of the four parameters incorporated into the stress-strain model, during rehydration with those of dehydrated products. The four examined parameters: maximum stress, maximum strain, elastic parameter and viscoelastic exponent seem to show a hysteresis phenomenon. It can be concluded that dehydrated product do not keep their viscoelastic behaviour after rehydration due to structural damages that occur during drying. 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 tendency, keeping their viscoelastic characteristics during rehydration close to those of dried materials. (C) 1999 Elsevier Science Ltd. All rights reserved.	en
heal.publisher	Elsevier Science Ltd, Exeter, United Kingdom	en
heal.journalName	Journal of Food Engineering	en
dc.identifier.doi	10.1016/S0260-8774(99)00063-1	en
dc.identifier.isi	ISI:000081211700006	en
dc.identifier.volume	40	en
dc.identifier.issue	4	en
dc.identifier.spage	269	en
dc.identifier.epage	277	en