THE FREEZE DRYING OF FRUIT JUICE FOR THE PREPARATION OF REFERENCE MATERIALS
The need for preparing reference materials for fruit juice determinations was expressed on several occasions in B.C.R. expert groups. The possibility to produce such reference materials is however conditioned by the availability of a method which allows to transform the original juice or concentrate in a better tenable form. On the request of B.C.R. a study was carried out to examine the possibilities of transforming orange juice into powder by freeze-drying, and the conditions required for its conservation. In general, the obtained powder is hygroscopic, and tends to cluster into large solid lumps. Under optimal conditions of lyophilisation combined with redrying of the powder before closing the bottles, a slightly cohesive but good tenable yellow orange powder can however be obtained. As compared to the original juice, this powder shows no loss of reducing sugars and has a normal glucose-fructose ratio. Moreover, most amino- acids as e.g. glutamine, valine, methionine behave normally. 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.
Bibliographic Reference: 3RD INTERNATIONAL SYMPOSIUM ON BIOLOGICAL REFERENCE MATERIALS, BAYREUTH/D, MAY 4-7, 1988, AVAILABILITY: CEC-LUXEMBOURG, DG-XIII/A2, BP 1907, MENTIONING PAPER OR
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Record Number: 1989126092200 / Last updated on: 1989-05-01
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