COMBINED EFFECTS OF OSMOTIC DEHYDRATION AND HIGH-PRESSURE SHIFT FREEZING ON APPLE MASS TRANSFER AND DRIP LOSS
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Date
2024
Journal Title
Journal ISSN
Volume Title
Publisher
Proceedings of the 24th International Conference and 44th Annual General Meetings of the Nigerian Institution of Agricultural Engineers (A division of Nigerian Society of Engineers)
Abstract
The combination of osmotic dehydration (OD) pretreatment with freezing, or osmotic dehydrofreezing
(ODF), is a novel technology applied to enhance the freezing preservation of fruits like apple. The study
focuses on the combined effect of OD pretreatment and high-pressure shift freezing (HPSF) on the mass
transfer and percentage drip loss of apple. The apple slices, with thickness of 1x1x1cm, were pretreated
with sucrose solution in a water baths at three levels of process conditions viz: osmotic solution
concentration (OSC:45, 55, and 65 oBrix), osmotic solution temperature (OST:25, 35 and 45 oC) and
osmotic process duration (OPD:30, 60 and 90 minutes) before freezing at pressures of 200 and 240 MPa.
The mass transfer including water loss and solid gain of the untreated (control) and osmotically
dehydrated frozen samples was evaluated using standard methods. The maximally dehydrated HPSF at
45 °Brix OSC, 35 °C OST, 60 minutes OPD and 240 MPa induced high solid gain value of 0.41 g/g and
initiated low water loss value 0.90 g/g (P ≤ 0.05)when compared with the untreated frozen sample that
had water loss of 4.02 g/g. Percentage drip loss of treated samples was significantly lower than those of
untreated ones at P ≤ 0.05 with minimum value of 0.33 % at 45 oBrix OSC, 35 oC OST, 30 minutes OPD and
240 MPa when compared with the untreated frozen sample that had value of 4.36%. In conclusion,
combination of OD pretreatment with HPSF is a promising technique for promoting the mass transfer
whilst reducing percentage drip loss of frozen apple after thawing.