Application of osmotic treatment in tomato processing—effect of skin treatments on mass transfer in osmotic dehydration of tomatoes

The applicability of Peleg?s model was investigated for predicting mass transfer kinetics during osmotic dehydration (OD) process of pears, at different concentrations (40%, 60% and 70% w/w) and temperatures (20?C, 35?C and 50?C) of sucrose solution. Increase in sucrose solution concentration resulted in higher water loss (WL) and solid gain (SG) values through the osmotic treatment period. After 360 minutes of osmotic treatment of pears, WL ranges from 23.71 % to 31.68 % at 20?C, from 24.80 % to 40.38 % at 35?C and from 33.30 % to 52.07 % at 50 ?C of initial weight of pears. The increase of dry mass of the samples, SG, after 360 minutes of osmotic treatment ranges from 3.02 % to 6.68 % at 20?C, from 4.15 % to 7.71 % at 35?C and from 5.00 % to 8.92 % at 50?C. Peleg?s rate constants k1WL and k1SG, decreased with increasing temperature, as well as decreased with increasing concentration of osmotic solution at constant temperature. Both capacity constants k2WL and k2SG also exhibits the inverse relationship between capacity constant and temperature, as well as concentration of the osmotic solution. The Peleg?s rate constants for WL and SG at all temperatures followed Arrhenius type relationship. The model predicted equilibrium values were very close to experimental ones, which is confirmed with high coefficients of determination and by the residual analysis.

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Evaluation of water loss and solute uptake during osmotic treatment of white radishes (Raphanus sativus L.) in salt-sucrose solution

Plant Science Today ◽

10.14719/pst.1422 ◽

2021 ◽

Author(s):

Nguyen Minh Thuy ◽

Nguyen Thi Ngoc Tham ◽

Vo Quang Minh ◽

Pham Thanh Vu ◽

Ngo Van Tai

Keyword(s):

Mass Transfer ◽

Water Loss ◽

Raphanus Sativus ◽

Sucrose Solution ◽

Osmotic Dehydration ◽

Mass Gain ◽

Solid Content ◽

Raphanus Sativus L ◽

Osmotic Treatment ◽

White Radish

White radish, scientifically known as Raphanus sativus L., is a yearly vegetable. Currently, it was being grown and widely used in the world, including Vietnam. These plants have been used as food or food processing. The osmotic treatment of vegetables involves the removal of water from plants in which the solids from the osmotic solution are transported to the plant material by osmosis. By this procedure, sucrose and saline solution are usually performed. White radishes were dehydrated in different hypertonic solutions by combined sucrose and NaCl at three different concentrations, including 9 runs. Mass transfer behaviour was applied according to three common models such as Fick’s second law, Weibull and Peleg’s equations based on the change of moisture and solid content of white radish during osmotic dehydration. The obtained results showed that the mass transfer was fast at initial stage and became slowly at the later stage. The effective moisture (Dm) and solid diffusivities (Ds) were ranged from 1.0186 to 1.2826x10-8 and from 1.0692 to 2.3322x10-8 (m2/s) respectively. The Peleg’s equation was found to be the best fitting for water loss and solid uptake thanks to the high determination coefficient (>97.64%) and the low average relative error (<3.174%). Raised up solution concentration resulted in higher water loss and mass gain.

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