Effects of Emulsifier Charge and Concentration on Pancreatic Lipolysis: 2. Interplay of Emulsifiers and Biles

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• 作者：Zahari Vinarov ; Slavka Tcholakova ; Borislava Damyanova ; Yasen Atanasov ; Nikolai D. Denkov ; Simeon D. Stoyanov ; Edward Pelan ; Alex Lips
• 刊名：Langmuir
• 出版年：2012
• 出版时间：August 21, 2012
• 年：2012
• 卷：28
• 期：33
• 页码：12140-12150
• 全文大小：455K
• 年卷期：v.28,no.33(August 21, 2012)
• ISSN：1520-5827

文摘

As a direct continuation of the first part of our in vitro study (Vinarov et al., Langmuir2012, 28, 8127), here we investigate the effects of emulsifier type and concentration on the degree of triglyceride lipolysis, in the presence of bile salts. Three types of surfactants are tested as emulsifiers: anionic, nonionic, and cationic. For all systems, we observe three regions in the dependence degree of fat lipolysis, 伪, versus emulsifier-to-bile ratio, f_s: 伪 is around 0.5 in Region 1 (f_s < 0.02); 伪 passes through a maximum close to 1 in Region 2 (0.02 < f_s < f_TR); 伪 is around zero in Region 3 (f_s > f_TR). The threshold ratio for complete inhibition of lipolysis, f_TR, is around 0.4 for the nonionic, 1.5 for the cationic, and 7.5 for the anionic surfactants. Measurements of interfacial tensions and optical observations revealed the following: In Region 1, the emulsifier molecules are solubilized in the bile micelles, and the adsorption layer is dominated by bile molecules. In Region 2, mixed surfactant-bile micelles are formed, with high solubilization capacity for the products of triglyceride lipolysis; rapid solubilization of these products leads to complete lipolysis. In Region 3, the emulsifier molecules prevail in the adsorption layer and completely block the lipolysis.