|Title||Bacterial cellulose as an alternative thickener for o/w emulsions: Comparison with common thickeners|
|Author(s)||Paximada, P.; Koutinas, A.A.; Scholten, E.; Mandala, I.|
|Event||ISFRS 2015, Zurich, 2015-06-07/2015-06-11|
Physics and Physical Chemistry of Foods
|Publication type||Abstract in scientific journal or proceedings|
|Abstract||Cellulose is the most abundant natural polysaccharide, being the major structural component of
plants. Chemically modiﬁed celluloses are well known food thickeners. Recently, besides them, bacterial cellulose (BC) has received attention. BC has good water binding capacity and suﬃcient network formation through formation of ﬁber-like structures. The role of BC as a thickener in the continuous phase of emulsions has not been extensively studied and the eﬀect on the rheological behavior of emulsions is not well known. Xanthan gum (XG) and locust bean gum (LBG) are hydrocolloids commonly used as thickeners in emulsions. However, both XG and LBG are high priced and the food industry would beneﬁt from cheaper alternatives. Hence, the objective of the present study was to investigate the eﬀect of BC (0 - 1 %wt) addition in whey protein isolate (WPI) (2 - 5 %wt) stabilized emulsions on the properties of the emulsions in terms of droplet size, stability and rheological behavior and to compare the rheological behavior to emulsions thickened with xanthan gum (XG) and locust bean gum (LBG). At lower BC concentrations (0.5 - 0.7 %wt), extensive aggregation led to unstable emulsions due to bridging ﬂocculation. However, at higher concentrations (1 %wt BC), stable emulsions were obtained due to either steric stabilization or network formation of BC ﬁbrils. The viscosity proﬁle of the BC emulsions showed three regions, including two shear thinning regions separated by a constant viscosity plateau (Newtonian). To compare the ability of BC to act as a thickener with XG and LBG, emulsions were prepared with diﬀerent thickener concentrations. Their rheological proﬁle showed that BC experienced similar shear thinning behavior as XG, but smaller amounts of BC was needed to obtain the same zero- shear viscosity. These results showed that BC is a good alternative for commonly used thickeners with future applications in the food industry.