###### Abstract  
In this work, grapes were coated with a multifunctional biosurfactant extract obtained from corn steep liquor after liquid-liquid extraction with ethyl acetate. This biosurfactant extract has been demonstrated to not only possess a surfactant capacity but also antimicrobial activity. Hence, it could be an excellent preservative for fruits, as it is more biodegradable and more biocompatible than chemically synthetized preservatives. However, before applying this biosurfactant as a preservative on fruits, it is necessary to study the changes in the surface properties of fruits produced by the addition of this bioactive compound. Therefore, in this work, grapes coated with an aqueous solution containing 1 g/L of the biosurfactant extract were subjected to surface analysis using non-invasive technologies, including profilometry. 2D digital photographs of the surface and parametric roughness of grapes were obtained. They revealed that the biosurfactant extract decreased the roughness of the grape surface compared with non-coated grapes and reduced the changes in the shape of the grapes over time. Moreover, it was observed that the biosurfactant extract increased the hydrophobicity of the grape surface observing higher contact angle compared with non-coated grapes. g 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 June 2021 22 22 June 2021 22 22 June 2021 22 22 22 22 22 22 22 2  
fungi, such as _Paecilomyces variotti_ and _Byssochlamys fulu_, at concentrations lower than their toxicity level, suggesting their application for extending the shelf-life of food products. However, the major drawback to the industrial application of biosurfactants is their higher cost in comparison with chemically synthetized surfactants and preservatives, as they are usually produced by biotechnological processes under controlled conditions [6; 7; 8]. Hence, for the realistic incorporation of biosurfactants into industrial formulations and products, it is necessary to work on the production of more cost-competitive biosurfactants. From this point of view, the biosurfactant extract obtained from corn steep liquor (CSL) could be an interesting alternative to chemically synthetized surfactants and preservatives, as it is spontaneously produced in corn steep liquor during the steeping step occurring in the corn milling industry, saving the cost of the biotechnological process [9; 10]. Regarding the characteristics of this biosurfactant extract, it has been demonstrated that it is a lipopeptide produced by a _Bacillus_[11; 12; 13], composed of C16-C18 fatty acids and amino acids containing glutamic acid/glutamine, aspartic acid/asparagine, glycine, alanine, arginine, proline, and leucine/isoleucine. Some of these amino acids are charged, providing the biosurfactant extract with an amphoteric characteristic. Therefore, aspartic acid and glutamic acid possess a negative charge, and glycine is amphoteric, presenting a negative or positive charge depending on the pH of the medium [1]. Regarding its function as a preservative, it possesses antimicrobial activity against bacteria and fungus [3; 4]; moreover, the biosurfactant from CSL is non-cytotoxic at a concentration of 1 g/L [14]. It is able to increase the solubilization in the water of active principles used in agrochemical formulations [15], and it is biodegradable with a t\({}_{1/2}\) lower than 15 days between 20-30 \({}^{\circ}\)C at pH 6 [16]. Consequently, this biosurfactant extract could be an interesting alternative to chemically synthetized preservatives and coating agents for prolonging the shelf-life of fruits from harvest to final consumption, which is one of the major problems in this industry. Furthermore, [PERSON] et al. [17] studied the effect of this biosurfactant extract during the maceration of two red wine grape varieties (_Vitis vinifera L. cv.