Osmotic dehydration of pineapple as a pre-treatment for further drying

Osmotic dehydration can be used as a pre-treatment for tropical fruits with the final aim of obtaining high quality dried fruit products. This concept was applied to South African grown Cayenne type pineapple pieces. The effect of osmotic dehydration on mass fluxes (water loss, solids gain and weight reduction) was investigated. Pineapple cylinders of 2 cm in diameter and 1 cm thick were immersed in sucrose solutions of 45, 55 and 65 °Brix at 30, 40 and 50 °C for 20, 40, 60, 20, 180 and 240 min. Experiments were conducted at both atmospheric pressure and applying a 200 mbar vacuum pulse during the first 10 min. Water loss and solids gain increased with temperature and concentration. Applying a vacuum pulse facilitated water loss especially at the highest concentration and temperature. Furthermore, the yield was improved by applying a vacuum pulse, as mass loss was less in those cases. Temperature affected mostly the water loss while the concentration of the solution affected mostly the solids gain. Prototypes of high/low water loss and high/low solids gain combinations were selected for quality evaluation.

[1]  John Shi,et al.  OSMOTIC DEHYDRATION OF FOODS: MASS TRANSFER AND MODELING ASPECTS , 2002 .

[2]  E. Azuara,et al.  Mass transfer during osmotic dehydration of pineapple rings , 2007 .

[3]  I. Ferguson,et al.  Postharvest responses to high fruit temperatures in the field. , 2000 .

[4]  J. Giese,et al.  Advances in microwave food processing , 1992 .

[5]  R. Mascheroni,et al.  Mass Transfer During Osmotic Dehydration of Pineapple , 2004 .

[6]  D. Knorr,et al.  Recent developments in osmotic dehydration: methods to enhance mass transfer , 2002 .

[7]  A. Chiralt,et al.  Vacuum impregnation and osmotic dehydration in matrix engineering: Application in functional fresh food development , 2001 .

[8]  A. Chiralt,et al.  Physical and chemical changes induced by osmotic dehydration in plant tissues , 2005 .

[9]  G. Bertolo,et al.  Present and future in process control and optimization of osmotic dehydration. From unit operation to innovative combined process: an overview. , 2004, Advances in food and nutrition research.

[10]  R. Paull,et al.  Preharvest weather conditions and pineapple fruit translucency , 1996 .

[11]  A. Lenart.  Osmo-convective drying of fruits and vegetables: technology and application , 1996 .

[12]  A. Chiralt,et al.  Pineapple Candying at Mild Temperature by Applying Vacuum Impregnation , 2002 .

[13]  R. Paull,et al.  Fruit temperature and crown removal on the occurrence of pineapple fruit translucency , 2001 .

[14]  H. Das,et al.  Modelling for moisture variation during osmo-concentration in apple and pineapple , 2004 .

[15]  Gustavo V. Barbosa-Cánovas,et al.  Engineering and food for the 21st century , 2002 .

[16]  A. Chiralt,et al.  Use of vacuum impregnation in food salting process , 2001 .

[17]  Pedro Fito,et al.  DRYING KINETICS OF APPLE CYLINDERS UNDER COMBINED HOT AIR–MICROWAVE DEHYDRATION , 2004 .

[18]  José M. Barat,et al.  Vacuum impregnation for development of new dehydrated products , 2001 .

[19]  K. Buckle,et al.  Osmotic dehydration of pineapple: kinetics and product quality , 1996 .

[20]  Pedro Fito,et al.  Modelling of vacuum osmotic dehydration of food , 1994 .

[21]  Tsu-Wei Chou,et al.  Microwave processing: fundamentals and applications , 1999 .

[22]  N. Rastogi,et al.  Mass transfer during osmotic dehydration of pineapple: considering Fickian diffusion in cubical configuration , 2004 .

[23]  Siaw Kiang Chou,et al.  EFFECT OF OSMOTIC PRE-TREATMENT AND INFRARED RADIATION ON DRYING RATE AND COLOR CHANGES DURING DRYING OF POTATO AND PINEAPPLE , 2001 .

[24]  A. Chiralt,et al.  Coupling of hydrodynamic mechanism and deformation-relaxation phenomena during vacuum treatments in solid porous food-liquid systems , 1996 .

[25]  A. Chiralt,et al.  Influence of vacuum treatment on mass transfer during osmotic dehydration of fruits , 1995 .