Layered food designs to create appetizing desserts: A proof-of-concept study.

Creating layers in foods is a culinary technique commonly used to diversify sensory experiences, but it has not been reported scientifically on its effect on hedonic and appetitive responses. This study aimed to investigate the use of dynamic sensory contrasts in layered foods to stimulate liking and appetite, using lemon mousse as a model. A sensory panel evaluated the perceived sour taste intensity of lemon mousses acidified by various amounts of citric acid. Bilayer lemon mousses with unequal distribution of citric acid across the layers to deliver higher levels of intraoral sensory contrast were developed and evaluated. A consumer panel evaluated the liking and desire to eat lemon mousses (n = 66), and a selection of samples was further investigated in an ad libitum food intake setting (n = 30). In the consumer study, bilayer lemon mousses with a layer of low acidity (0.35% citric acid w/w) on top and higher acidity (1.58 or 2.8% citric acid w/w) at the bottom showed consistently higher liking and desire scores than their corresponding counterparts with identical acid levels equally distributed in a monolayer. In the ad libitum setting, the bilayer mousse (top: 0.35; bottom: 1.58% citric acid w/w) had a significant 13% increase in intake compared to its monolayer counterpart. Modulating sensory properties across food layers with different configurations and layer compositions can be further explored as a tool to design appetizing foods for consumers at risk of undernutrition.

Formulation of Heat-Induced Whey Protein Gels for Extrusion-Based 3D Printing.

This study investigated the extrusion-based 3D printability of heat-induced whey protein gels as protein rich food inks. In particular, the effects of ionic strength by the addition of NaCl (0-250 mM), protein content (10%, 15%, 20%), fat content (0%, 10%), and partial substitution of whey protein isolate (WPI) with microparticulated whey protein (MWP) or micellar casein isolate (MCI) on printability were assessed. Texture analysis, specifically Young's modulus, rheological measurements including yield stress, and creep-recovery behavior were used to characterize the gels. Modifications of the formulation in terms of ionic strength, increased protein content, and the formation of emulsion gels were insufficient to maintain a continuous extrusion process or shape stability after printing. However, the substitution of WPI with MWP created more viscoeleastic gels with improved printability and shape retention of the 3D cube structure after deposition. The partial replacement of WPI with MCI led to phase separation and 3D-printed cubes that collapsed after deposition. A narrow range of rheological material properties make WPI and MWP emulsion gels promising food inks for extrusion-based 3D printing.

Using Ethylcellulose to Structure Oil Droplets in Ice Cream Made with High Oleic Sunflower Oil.

In order to mimic physical characteristics of solid fat, ethylcellulose (EC) was used as an oleogelator in ice creams made with high oleic sunflower oil (HOSO). The aim was to improve structure of ice cream made with fully liquid vegetable oil by inhibiting droplet coalescence and to enable a colloidal fat network by making the oil droplets solid-like. Two different methods for incorporating EC into emulsions were developed, both designed to involve high pressure homogenization of ice cream mixes as in traditional ice cream production. Ice creams based on 10% HOSO and 1% EC (cP10 or cP20) were successfully made. Two types of emulsifiers in the ice cream formulations were tested: unsaturated monoglyceride (GMU) or saturated mono-diglyceride. GMU enhanced fat destabilization of ice cream resulting in coalescence of unstructured HOSO droplets. Presence of EC in HOSO based ice cream inhibited coalescence of oil droplets and the structure of the lipid phase resembled the small, evenly distributed fat globules in the reference ice cream made with saturated coconut fat. The resisting effect toward coalescence increased with higher molecular weight of EC, accordingly oil droplets made with EC cP20 were smaller compared to oil droplets containing EC cP10. EC did not increase the amount of air that was incorporated in ice creams based on HOSO, irrespective of the type of emulsifier. In general the overrun in HOSO-based ice creams (with and without EC) was considerably lower compared to ice cream made with coconut fat. PRACTICAL APPLICATION: Interest for product development of ice cream based on unsaturated liquid oil is increasing. To compensate for the lacking fat crystals that provide structure and stability in traditional ice cream, the liquid oil is transformed into solid-like material by ethylcellulose (EC). The process of ice cream includes high pressure homogenization, and in order to adapt to this process step, two new methods of incorporation of EC into the oil of ice cream mixes were developed.

The effects of low-molecular-weight emulsifiers in O/W-emulsions on microviscosity of non-solidified oil in fat globules and the mobility of emulsifiers at the globule surfaces.

Electron Spin Resonance spectroscopy (ESR) was used to measure the mobility of the spin probe TEMPO in O/W-emulsions. This allowed determination of temperature-dependent microviscosity of the liquid fraction in lipid globules. Six hydrogenated palm kernel oil (HPKO) based emulsions containing caseinate and different combinations of lactic acid ester of monoglyceride (LACTEM), unsaturated monoglycerides (GMU) or saturated monoglyceride (GMS) were studied. The non-solidified oil in emulsions made with LACTEM+GMU had a high microviscosity, whereas the emulsion made with GMS had a low microviscosity. Also the partitioning of TEMPO between the lipid and aqueous phases was found to be highly temperature dependent, most likely due to the change of solid fat content with temperature. This behaviour may mimic the partitioning of aroma compounds in emulsions. The spin probe 5-doxylstearic acid was used to study the mobility of the components at the lipid globule surfaces. At 5°C all emulsions had a very low surface mobility. At 25°C the mobility of the spin probe was found to be correlated to the surface protein load. Emulsions with GMU had a high protein surface coverage and low mobility of the spin probe on the droplet surfaces. Conversely, in presence of LACTEM and GMS, the protein surface loads decreased and high surface mobilities were observed. Based on these results it is argued that the high macroscopic viscosity and lipid agglomeration of emulsions containing GMU is due to a lipid globule-protein-network where the lipid globules are connected via caseinate.