Composition of Orange Juice Cloud

Abstract

SUMMARY Reported for the first time are analyses of materials identified with and contributing to the cloud of orange juice. Hexane‐soluble materials provided up to one‐fourth of the cloud‐producing components. In contrast to the composition of structural components of the fruit, cloud components insoluble in alcohol, acetone, and hexane were shown to be rich in nitrogen (ca. 7%), pectins (ca. 80%), and phosphorus (ca. 1.5% as the pentoxide) and to be very low in cellulosic components (ca. 2–5%). This is evidence that cloud originates in the juice cells rather than from mechanical disintegration of structural tissue. No appreciable difference in cloud composition was observed between fruit varieties or between freeze‐damaged and normal fruit.

Calcium and pH influence on orange juice cloud stability

“…15 The Malvern particle size data indicated particle association and dissociation of cloud particles prior to onset of clarification. In this study, the D [3,2] values increased (from ∼7-9 µm to ∼11-15 µm), decreased (back to ∼7-10 µm), then increased again (to ∼11 decrease occurred again. The pH 5.5 juice samples showed a similar trend of particle size change, but the first increase in D [3,2] values were higher and more variable than D [3,2] values observed for 4.0 C juices.…”

“…In this study, the D [3,2] values increased (from ∼7-9 µm to ∼11-15 µm), decreased (back to ∼7-10 µm), then increased again (to ∼11 decrease occurred again. The pH 5.5 juice samples showed a similar trend of particle size change, but the first increase in D [3,2] values were higher and more variable than D [3,2] values observed for 4.0 C juices. In agreement with the Brookhaven data, it is apparent that the final particle size for pH 5.5 samples is smaller than that for pH 4.0 samples.…”

“…7 show the Malvern data for sample 4. 16 who also used fresh Valencia orange juice, reported a D [3,2] peak at a smaller size near 3 µm. The differences in particle sizes observed for cloud-stable juice in this study may be related to the method of particle size determination and/or preparation of pulp-free juice.…”

“…The cloud contributes much of the color, flavor, turbidity, and aroma of orange juice. 1 Scott et al (1965) suggested that the fraction of orange juice with the finest particles, the cloud, had a composition quite different from the rest of the juice and that the cloud should be treated as a separate component and not as tiny fragments of pulp. 2 Orange juice cloud is made up of protein, pectin, lipids, cellulose, and hemicellulose.…”

Multivariate Analysis for Classification of Commercial Orange Juice Products by Volatile Constituents Using Headspace Gas Chromatography

“…None of the 19 oxygenated compounds in the standard mixture were affected by this equilibration period. Previous reports had indicated the presence of such an equilibration between pulp and juice serum for peel oil (25), and for hydrocarbon components in particular (26). Duplicate GC runs at four different concentrations selected to cover the range of values found in the 27 juice samples were employed in determining standard curves.…”