Shortening replacement by emulsion and foam template hydroxypropyl methylcellulose (HPMC)-based oleogels in puff pastry dough. Rheological and texture properties.

Shortening plays an essential function in the formulation of sweet laminated bakery products, but has a potential health risk due to their high percentage of saturated fatty acids. In this paper, the feasibility of hydroxypropyl methylcellulose (HPMC) oleogels prepared with emulsion template (ET) and foam template (FT) approaches as fat sources in a puff pastry dough was investigated. Spreadability and thermal properties of control shortening, 100% ET and FT oleogels and shortening/oleogel (50/50) blends were measured. The different systems were applied as the fat source in a puff pastry dough, and their effect on rheological and texture properties was investigated. Results showed that partial replacement of shortening with oleogels could significantly decrease the firmness values (from 115 to 26 N) (P < 0.05) and increased the spreadability of shortening. The methodology to prepare the oleogel (FT or ET) also significantly affected the texture parameters. FT blends had the highest spreadability with significantly lower firmness values and area under the curve. Thermal values showed that both oleogels could slightly increase the melting point of shortening from 47 to 50 °C. The replacement of shortening with oleogel decreases the viscoelasticity of puff pastry dough and increases its thermal stability but does not significantly change dough viscoelasticity in the shortening/oleogel mixture. These results indicated that both oleogels have promising potential to replace shortening in puff pastry dough formulations, but the ET oleogel showed a more similar behavior to the control shortening than the FT oleogel.

Rheological properties of emulsion templated oleogels based on xanthan gum and different structuring agents.

Oleogel design based on emulsions using food grade polymers is a potential strategy for replacing saturated and trans fats. The aim of this paper is the characterization of sunflower oil-based oleogels structured by a non-surface-active polysaccharide, xanthan gum (XG), in combination with different structuring agents, through an emulsion template approach, which consists in the dehydration of the continuous phase of an oil/water emulsion. Four types of molecules with different origins were used: a synthetic one, polysorbate Tween 80, and other three from natural sources: a protein (whey protein, WP), a lipid (soy lecithin, SL) and a polysaccharide (locust bean gum, LBG). All the emulsions had a high shear thinning character (s = 0.45) and a weak gel behaviour (tanδ = 0.2). Only the LBG emulsions presented significant differences, with higher values of viscosity and viscoelastic moduli. The resulting oleogels showed high gel strength, exhibiting a marked elastic behaviour typical of structured solid systems (G'>G'' and tanδ = 0.06). SL oleogels stood out for presenting the lowest firmness, although internal structure seems to be similar to the rest. Regarding to stability, measurements indicated a great oil binding capacity (90% approx.) after 24 h. It is concluded that obtaining stable and solid-like oleogels with liquid oil using a hydrophilic polymer (XG) combined with different food-grade structuring agents was possible. These systems have great potential in food reformulation, especially for saturated fat substitution.