Forward osmosis (FO) technology has drawn increasingly research interests in juice concentration due to its great advantages in producing high-quality concentrated juice. However, the lack of suitable draw solutes is a significant obstacle hindering the practical application of FO for juice concentration. In this work, a series of food preservatives were systematically investigated as draw solutes in the FO system. By careful evaluation of these preservatives, we selected 4 M sodium diacetate (SDA) as one model of draw solution to concentrate grape juice in a 72-h continuous FO test. The concentrated grape juice with 5.14 folds was obtained with no loss of the titratable acidity and the vitamin C content. Moreover, the SDA accumulation in the concentrated product was only 2.0 ± 0.1 g/kg, after being diluted to regenerate juice, the preservative concentration in juice is 0.39 g/kg, which is lower than the safety limit of SDA (0.5 g/kg, FAO)....

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