## 1 Introduction  
In recent decades, the demand for healthier foods has risen, boosting the interest of the food industry to reformulate a wide variety of products. This reformulation includes reducing a specific component (such as sugar or fat content) or the use of naturally derived ingredients [1], but without compromising the food safety and the sensory quality. Fulfilling the latter requirements is especially challenging in food products where fat is the primary component, for example, in ice creams, vegetable spreads (i.e., peanut butter), and salad dressings (i.e., mayonnaise), because the fat plays a crucial role as structuring agent, contributing to the development of texture [2].  
Mayonnaise is a worldwide-consumed seasoning used in several types of foods, for instance, sandwic, salads, hamburgers, hot dogs, seafood, and others. The traditional formulation contains approximately 70-80% of oil, vinegar, and spices; however, the consumers usually perceive its high oil content as potentially unhealthy [3]. This conception led to the elaboration of low-fat mayonnaise, which contains 20-40% oil, this has been possible by using thickening agents such as modified starches or gums to develop texture and physical stability in the product [4; 5; 6]. However, the use of the latter ingredients might have some sensory disadvantages. For instance, the texture or taste of the product could be negatively affected [7; 8], and some of these ingredients (modified starches) could be perceived as potentially harmful [9].  
One alternative to overcome the negative texture impact of reducing the fat content in mayonnaises is the use of Emulsion-Filled Gels (EFG). The EFGs are gel matrices in which emulsified oil droplets replace the water phase of the gel. These systems are stable against creaming, flocculation, and coalescence, have a gel-like behavior, and they can be easily produced with a wide range of biopolymers such as gums (pectin, tragacanth gum, gellan gum, alginates, carrageenanan) and proteins [10; 11]. To date, the application of EFGs in mayonnaise has been demonstrated to mimic the sensory properties (texture and mouthfeel) of the regular product using egg yolk (as emulsifier), tragacanth gum, and sodium alginate (as a thickening and gelling agents) [12; 13], fulfilling the actual demands of the consumers (low-fat and naturally derived ingredients).  
There are many sources for obtaining natural derived biopolymers, for instance, cereals, tubers, oilseeds, and algae. These latter are comprised by macroalgae and microalgae, where the first one is a common source of sodium alginate; this biopolymer is used as thickening and gelling agent, and one of the most important characteristics of this compound is the irreversible gelation when is combined with ionic salts, for example, calcium chloride [14]. In the case of microalgae, the _Arthospira platensis_, commonly known as spirulina, is nowadays an important raw material to extract high valuable ingredients, because it contains unsaturated fatty acids (omega 3), pigments (phyocyanin), and a high concentration of proteins (40-50%) [15; 16] with promising applications due to its emulsion capacity (approximately 60%) and stability (ranging from 80-100%) [17; 18; 19; 20].  
In our previous work [21], it was observed that the consumers of mayonnaise (in Mexico) perceived the proteins as natural ingredients and have good acceptability, hence, it was decided to produce mayonnaises using egg yolk, vegetable proteins, and sodium alginate. Therefore, the present study aimed to exploit the techno-functionality (i.e., emulsifying properties and water and oil holding capacities) of the _A. platensis_ protein in combination with sodium alginate to produce low-fat mayonnaises (using an EFG approach) with comparable physical and sensory characteristics than a commercial low-fat mayonnaise.