Effect of trehalose and ultrasound-assisted osmotic dehydration on the state of water and glass transition temperature of broccoli (Brassica oleracea L. var. botrytis L.)
- Authors: Xin, Ying , Zhang, Min , Adhikari, Benu
- Date: 2013
- Type: Text , Journal article
- Relation: Journal of Food Engineering Vol. 119, no. 3 (2013), p. 640-647
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- Description: The effects of trehalose and ultrasound-assisted osmotic dehydration on the glass transition temperature (Tg′) and the state of water in broccoli were analyzed by using differential scanning calorimetry (DSC), low field nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI). The results showed that osmotic dehydration using trehalose can affect the Tg′ of broccoli by changing the state of water within the sample structure. The values of Tg′ of the osmotically dehydrated broccoli samples ranged between -27.52 C and -23.31 C, which constituted an increase of about 2-6 C compared with that of the untreated sample. Compared with the normal osmotic dehydration with 2 h, ultrasound-assisted dehydration with shorter time (30 min) could get the higher value of Tg′ by increased the water loss and accumulation of trehalose and decrease the mobility of water in the broccoli cell tissue. However, when the ultrasound treatment time was 40 min, it resulted into decrease in Tg′ indicating the important role of treatment time in ultrasound-assisted osmotic dehydration process. © 2013 Elsevier Ltd. All rights reserved.
- Description: 2003011222
Research trends in selected blanching pretreatments and quick freezing technologies as applied in fruits and vegetables : A review
- Authors: Xin, Ying , Zhang, Min , Xu, Baoguo , Adhikari, Benu , Sun, Jincai
- Date: 2015
- Type: Text , Journal article
- Relation: International Journal of Refrigeration Vol. 57, no. (2015), p. 11-25
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- Description: Abstract This paper presents a comprehensive review of recent developments in thermal (radio frequency, microwave and ohmic), non-thermal (high pressure, ultrasound and infrared) methods in blanching pretreatment. Recent developments in quick freezing technology (high pressure, dehydrofreezing and ultrasound-assisted) as applied to freezing of fruits and vegetables are also reviewed. The thermal and non-thermal blanching methods provide rapid and uniform heating; reduce the loss of soluble nutrients and minimize thermal damage compared to conventional hot water blanching. High pressure freezing seems to promote instantaneous and homogeneous ice nucleation in fruits and vegetables. Dehydrofreezing is capable of reducing the damage to plant texture by removal partial of water before freezing. Ultrasound-assisted freezing is found to be effective in the initiation of nuclei and subsequent growth of crystals. More fundamental researches are needed for better design and scale up, so that these technologies can be transferred from laboratory to industry. © 2015 Elsevier Ltd and IIR.