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Literature & Scientific Research
Acid beverage floc; protein-saponin interactions and an unstable emulsion model
Abstract
The occurrence of acid beverage floc (ABF) in acidified carbonated beverages has long been attributed to the
presence of saponins. We have examined this assertion and have found evidence to suggest that traces of protein may
also be a key factor, along with lipid material present in the floc. Turbidity levels of beet sugar protein (0.001 wt.%)
and saponin (0.001 wt.%) solutions were examined over time using spectrophotometry. At neutral pH, no change in
turbidity was observed in any combination (individually or mixed). Furthermore, acidified (pH 2) saponin and protein
solutions, considered separately, also exhibited no change. However, a mixture of equal concentrations at pH 2
showed an initial increase in turbidity up to 2 h after mixing, followed by a decrease over the ensuing 12 h. Interfacial
tension measurements also indicated interactions between the protein and saponin at pH 2. Photon correlation
spectroscopy (PCS-Malvern Zetasizer 4) was used to quantitatively examine the particle size distributions and
aggregation of a model, highly dilute dispersion, of bromohexadecane in 20 wt.% sucrose solution, prepared with a
jet homogenisor. Beet sugar saponin (0.001 wt.%) and protein (0.001 wt.%) were added to the dispersion, and their
emulsion-stabilising effects examined via oil droplet size measurement over time. At neutral pH, the size of oil
droplets in the dispersion was unaffected by the addition of saponin or protein. At pH 2, the presence of saponin
again caused no effect on droplet size. However, in acid conditions, protein appeared to destabilise the dispersion.
The results indicate that the key to controlling the ABF problem may be the ratio of saponin to protein in the
product, which may or may not stabilise dispersed lipid, depending on their interactions. © 2001 Elsevier Science
B.V. All rights reserved.
by Patrick A.J. Morton and Brent S. Murray |
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Evaluation of Yucca schidigera as food grade saponins
Short Paper. Author B. L. Olser Food and Drug Research Laoratories, Inc., Maspeth, New York 11378, USA. November 17, 1965
Introduction: The recent review of the legal status and toxicity of saponins by George (1965) prompts us to report hethertounpublished data on a source of saponin not mentioned in this review despite the fact that it is perhaps the most extensively used foaming agent in the popular American beverage, root beer, as well as other frothy drinks. This product is derived from a California desert plant known as Yucca mohavensis Sarg. (or Y. schidigera Roezl ex Ortegies of the family Liliaceae.
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