Optimization of an Emulsion Filled Gel with Chickpea Protein Isolate

The growing interest in healthiness and sustainability has focused attention on developing lipid systems that can reduce the amount of food fat content and act as possible carriers of important bioactive compounds extracted from food wastes. A face-centered Central Composite Design (CCD) was applied to develop an emulsion filled gel, considering as main factors the corn oil concentration (15, 37.5, and 60% v/v) and chickpea protein isolate (ChickP, Rehovot, Israel) concentration in the water phase (8, 12, and 16% w/v). For comparison, the CCD was applied also to a single emulsion with the same levels of corn oil and lecithin as emulsifier (0.5, 1.5, and 2.5% w/v on the water phase). Chickpea proteins confirmed their outstanding gelling properties, giving apparent viscosity values up to 2380 ± 123 mPa·s, whereas lecithin emulsions only reached up to 144 ± 11 mPa·s. Creaming stability was at the highest (i.e., 100%) until 14 days of storage at 4°C for both the gelled and the single emulsions. On the contrary, stability index was significantly lower in lecithin emulsion than in emulsion filled gels. Response Surface Methodology and desirability function were applied for optimization of each type of emulsion, obtaining 2.5% lecithin and 58.5% corn oil for single emulsion, and 16% chickpea protein isolate with 60% corn oil for emulsion filled gel. The promising results pave the way for the application of these advanced systems as carriers of bioactive compounds to design food products with low-fat content, clean labels, and an improved nutritional and technological profile.