Role of Hydrocolloids in the Creaming of Oil in Water Emulsions

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• 作者：Genoveva Vé ; lez ; Miguel A. Ferná ; ndez ; José ; Mu&ntilde ; oz ; Peter A. Williams ; and Robert J. English
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2003
• 出版时间：January 1, 2003
• 年：2003
• 卷：51
• 期：1
• 页码：265 - 269
• 全文大小：136K
• 年卷期：v.51,no.1(January 1, 2003)
• ISSN：1520-5118

文摘

The influence of guar gum and xanthan gum on the creaming of 10% oil in water emulsions hasbeen investigated. The presence of very low concentrations of the polysaccharides (typically< ~0.075%) was found to induce depletion flocculation of the emulsion droplets and increased therate of creaming. However, at higher polysaccharide concentrations (typically > ~0.1%) the creamingrate was reduced due to the increased viscosity of the aqueous phase. For most systems a delayperiod was noted before creaming started, which was found to be dependent on the zero shearviscosity of the continuous phase and independent of polysaccharide type. The delay period increasedsignificantly at zero shear viscosities approaching 1 Pa s. A mathematical model has been used tofit the creaming rate profiles and a simple exponential relationship obtained between delay time andpolysaccharide concentration.Keywords: Emulsion stability; depletion flocculation; delay time for creaming; xanthan gum; guargum; oil in water emulsions