*3.5. Texture Profile*

Studies on the texture profile of food emerged due to the need for a better understanding of human sensorial sensitivity in relation to food. Over time, such studies have acquired a greater relevance due to the need for the presence of functional ingredients and the emergence of innovative technologies that improve texture to ensure quality and satisfy the preferences of consumers [43].

Table 7 shows the results of the texture profile analysis of the cookies after the addition of the biosurfactant. The Tukey test revealed that the addition of the biosurfactant did not cause any significant change in most of the variables analyzed (hardness, cohesiveness and sponginess).

**Table 7.** Texture profile analysis of the dough 24 h and 45 days after baking for standard formulation, formulation A (1% biosurfactant), formulation B (0.5% biosurfactant) and formulation C (0.25% biosurfactant) (data expressed as mean ± SD of triplicate determinations).


a, b, c: Different letters in same column denote statistically significant differences (*<sup>p</sup>* <sup>≤</sup> 0.05, Tukey test). The values for each texture component in the different formulations were compared statistically taking the standard formulation as a reference. \* Asterisk on same line denotes a significant difference after storage (*p* ≤ 0.05, Tukey test).

> The similarities among the results for the different formulations are important for the maintenance of the typical characteristics of a cookie; the bioemulsifier proved to be effective in this sense, having led to an improvement in the properties of the cookies in comparison with those of the standard formulation. A considerable difference in hardness was found for the cookie made with formulation B containing 0.5% biosurfactant especially in comparison with the standard formulation, which suggested an increase in crispness when using this biosurfactant concentration. The significant increases in cohesiveness and sponginess can be expected to enhance the chewability.

> Zouari et al. [28] reported that the addition of the biosurfactant produced by *B. subtilis* at a concentration of 0.1% to a cookie formulation promoted a significant improvement in the texture profile of the dough; moreover, the action of this bioemulsifier was more pronounced than that of a commercial emulsifier (glycerol monostearate). Kiran et al. [44], who incorporated a lipopeptide at a concentration of 0.75% to a muffin formulation, found an improvement in the final softness due to the increase in sponginess and cohesiveness as well as a reduction in hardness.

> The literature offers other reports on the potential of microbial biosurfactants [1,3,45] but with few examples of applications in the formulation of products for human consumption. Such examples include the addition of microbial bioemulsifiers to the formulations of mayonnaises [46], cupcakes [31] and cookies [22].

> The biosurfactant at the lowest concentration (formulation C) did not promote a significant improvement in the texture profile compared with the standard formulation. However, cohesiveness was maintained after 45 days of storage, which did not occur with the standard formulation. Campos et al. [40] found that the use of a bioemulsifier produced by *C. utilis* at a concentration of 0.7% offered a greater stability and hardness to a salad

dressing formulation after 30 days of storage; the product was considered a good emulsifier compared with commercial products such as guar gum and carboxymethylcellulose.

In the production of food, the useful life of emulsions during long-term storage should be considered to ensure the consistent quality of the product. Studies have shown that the oily phase composition and the type of emulsifier exert significant effects on the long-term stability and sensorial properties such as spreadability, viscosity and appearance [36].

As the biosurfactant investigated herein had no significant negative effect from the statistical standpoint on the texture profile of the cookie, it could be considered to be a potential ingredient for the food industry. A simple assessment of aroma, flavor, color and texture revealed no significant differences between the formulations containing the biosurfactant and the standard formulation. However, sensory assessments are needed and the biosurfactant should be added to other formulations of flour-based products to determine whether it can be incorporated into other food without compromising the desired characteristics. Such investigations could expand the applications of this biosurfactant.
