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Type:	Artigo de Periódico
Title:	Performance of Quillaja bark saponin and β-lactoglobulin mixtures on emulsion formation and stability
Authors:	Janaína Teles de Faria Eduardo Basílio de Oliveira Valéria Paula Rodrigues Minim Luis Antonio Minim
Abstract:	The emulsifying properties of a mixture of Quillaja bark saponin (QBS) and b-lactoglobulin (β-lg) were evaluated under different pH conditions (7e9) and NaCl concentrations (0e200 mmol$Lβ1) and compared to the individual components. The formation and stabilization of oil-in-water emulsions were evaluated through visual analysis, droplet size distribution, droplet surface electrical charge (z-potential), and emulsion rheology. Both pH and NaCl concentration affected the properties of these emulsions in different ways, depending upon the QBS: β -lg ratio. QBS and/or β -lg emulsions had a relatively high negative droplet charge at pH ranging from 7 to 9 (- 76.7 to -17.8 mV), which decreased in magnitude with decreasing pH or with increasing NaCl concentration. All emulsions were polydisperse and presented relatively small average droplet diameters (236e491 nm). Steady-state flow measurements revealed the non-Newtonian, shear-thinning behavior of all emulsions, which was properly described by the Herschel-Bulkley model with a small yield stress (12.9e214.8 mPa) and low apparent viscosity at 100 sβ1 (1.81e2.97 mPa s). The emulsions were characterized as weak gels by dynamic oscillatory measurements. Most of the emulsions comprising QBS, β-lg, or a mixture of both were stable against droplet coalescence over a pH and NaCl concentration range. Regardless of the tested emulsifier, phase separation did not take place, although droplet creaming was observed. Emulsions comprising QBS and β-lg, both independently and mixed, showed similar emulsifying properties. However, the mixture of these appeared to provide emulsions with improved stability when compared to QBS and β-lg emulsions. The good stability of these emulsions can be attributed to the increased electrostatic repulsion and steric stabilization conferred by the two emulsifiers concurrently.
Subject:	Demulsificação Potencial zeta Saponinas
language:	eng
metadata.dc.publisher.country:	Brasil
Publisher:	Universidade Federal de Minas Gerais
Publisher Initials:	UFMG
metadata.dc.publisher.department:	ICA - INSTITUTO DE CIÊNCIAS AGRÁRIAS
Rights:	Acesso Aberto
metadata.dc.identifier.doi:	10.1016/j.foodhyd.2017.01.013
URI:	http://hdl.handle.net/1843/47835
Issue Date:	2017
metadata.dc.url.externa:	https://doi.org/10.1016/j.foodhyd.2017.01.013
metadata.dc.relation.ispartof:	Food Hydrocolloids
Appears in Collections:	Artigo de Periódico

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