The freeze-drying of orange juice for the preparation of reference materials
1988
Kramer, G.N. (Commission of the European Communities, Geel (Belgium). Joint Research Center, Central Bureau for Nuclear Measurements) | Angelis, L. de | Pauwels, J. | Ooghe, W. | Belliardo, J.J.
The possibility of producing fruit juice reference materials in conditioned by the availability of a method which allows the transformation of the original juice or concentrate into a better physically stable form. Therefore a feasibility study of the transformation of orange juice by freeze-drying was carried out. In general, the obtained powder is hygroscopic, and tends to agglomerate into large solid lumps. Under optimal conditions of freeze-drying combined with redrying of the powder before closing the bottles, a slightly cohesive but physically stable yellow orange powder can however be obtained. Compared to the original juice, this shows no loss of reducing sugars and has a normal glucose-fructose ratio. Moreover, most amino-acids e.g. asparagine, methionine, lysine and arginine are not affected by freeze-drying. Based on the study of a limited number of important fruit juice parameters, it may be concluded that freeze-drying seems very promising in order to obtain an orange juice reference material, which after redissolution in water keeps the original chemical orange juice properties
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