GLASS TRANSITIONS AND ICE CRYSTALS IN BLACKCURRANTS AND REDCURRANTS
Glass transition as a function of moisture content was determined in blackcurrants Selechenskaya’ and Zagadka’ and in redcurrant cultivar Red Dutch’. Sorption experiments were carried out in chambers at controlled aw, at 30 ℃. Samples studied were fresh (for the desorption process) and previously freeze-dried (for the adsorption process). Glass transition of samples equilibrated to different moisture contents were analysed by DSC. Gordon and Taylor equation was used to model the water plasticization effect. Fitted glass transition temperature of anhydrous solids Tg(as) of blackcurrants and red currants lies between 30.21 and 41.69 ℃, and Gordon-Taylor constants k – between 3.59 and 4.05. The mass fraction of non-freezable water in evaluated samples (Wg) was 23.44 to 24.19. If water content before freezing is reduced to 70％, mass fraction of ice crystals in the samples, stored at the temperature -20 ℃, decreases to 52.7％ - 53.2％ from the total sample mass.
S.Kampuse G.Moraga I.Skrupskis A.Aboltins
Department of Food Technology, Faculty of Food Technology, LUA, Jelgava, Latvia Department of Food Technology, Polytechnic University, Valencia, Spain Department of Nutrition, Faculty of Food Technology, LUA, Jelgava, Latvia Department of Mathematics, Faculty of Information Technologies, LUA, Jelgava, Latvia
国际会议
The 22nd International Congress of Refrigeration(第22届国际制冷大会)
北京
英文
2007-08-21（万方平台首次上网日期，不代表论文的发表时间）