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To develope a process by which liquid foods can be stored in the liquid state at the froxen storage temperature, suitable cryoprotectants were selected. Orange juice, chosen as an example of liquid foods, was stored with combined cryoprotectants at - 15℃, and quality changes of orange juice during storage were evaluated. Among 7 cryoprotectants tested, NaCl solution had lower initial freezing point than others, and initial freezing points of glucose, fructose, glycerol, propylene glycol and citric acid were close to each other. Considering flavor quality of orange juice, cryoprotectants suitable for reducing freezing point of orange juice were glucose, fructose, glycerol, and citric acid. Combined cryoprotectants for reducing freezing point of 3 and 4 folds concentrated orange juice to -15℃ consisted of 10% glucose, 8% frutose, 4.6% glycerol and 3% citric acid, and 5.5% glucose, 4.5% fructose, 4.6% glycerol, and 3% cirtric acid, respectively. When destruction of ascorbic acid, sedimentation volume and sensory flavor score of orange juice stored with combined cryoprotectants at -15℃ and the control stored at -18 were compared, there were no significant differences. These results indicated that liquid foods with suitable combined cryoprotectants could be stored at -15℃ or below in the liquid state without adverse effect on quality of the stored products.
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