Study of the stability at coalescence in mucilage emulsions

QUINZIO CLAUDIA, CORVALÁN MELISA, LOPEZ BEATRIZ, ITURRIAGA LAURA.

Joao Pessoa Paraiba. Brasil

Congreso; International Cactus Pear Congress.; 2007

Cactus International Society

Study of the stability at coalescence in mucilage emulsions   Quinzio Claudia, Corvalán Melisa, Mishima Beatriz, Iturriaga Laura ICQ, - FAA-UNSE. Av. Belgrano (S) 1912. 4200. Santiago del Estero, Rep. Argentina e-mail: ibitur@arnet.com.ar   Mucilage is a mucopolysaccharide found in cacti cladodes (Opuntia ficus indica L. Mill.) and the same as hydrocolloids modify food functional properties. Presence of a low molecular weight protein fraction has been reported. It is known that polysaccharides such as the xanthan (XG) and guar gums (GG) are used in the formulation of emulsions. Since the latter has a 1-2% protein content that conveys it those amphyfilic characteristics needed for the stabilising activity, the Opuntia spp. mucilage might be used as an emulsifying agent. Thus, this work was aimed at evaluating stability at coalescense in emulsions prepared using mucilage and comparing them against that of commercial hydrocolloids emulsions. Isoviscose solutions of freeze-dried mucilage (FM), GG, XG, and carboxymetylcellulose (CMC) were prepared. In turn, 1:5 emulsions (v:v; oil: solution) were prepared using the NATURA® commercial oil and a polysaccharide solution, and homogenised with a blender for 4 min. Emulsion stability (EE) at coalescence was evaluated by centrifugation at 10.000 rpm for 10 min and registering the lipid phase retained. In addition the native mucilage-based emulsion stability was evaluated and apparent viscosities were determined using the TA Instruments AR 1000 rotational rheometer. The results showed that both XG and FM were the best stabilizing agents with 100% EE. The CMC displayed a 12% EE, while the GG and native mucilage (2%) at 89-90% one. They all indicate that the mucilage has stabilizing properties similar to those of the hydrocolloids under study.   Key words: amphyfilic, hydrocolloids, polysaccharides, rheology, viscosity.