Relation between Droplet Size Distributions and Physical Stability for Zein Microfluidized Emulsions

Abstract

settingsOrder Article Reprints Open AccessArticle Relation between Droplet Size Distributions and Physical Stability for Zein Microfluidized Emulsions by Jenifer Santos 1,*ORCID,Luis Alfonso Trujillo-Cayado 1,*ORCID,Francisco Carrillo 1ORCID,María Luisa López-Castejón 1ORCID andMaría Carmen Alfaro-Rodríguez 2ORCID 1 Departamento de Ingeniería Química, Escuela Politécnica Superior, Universidad de Sevilla, c/Virgen de África, 7, E41011 Sevilla, Spain 2 Departamento de Ingeniería Química, Facultad de Química, Universidad de Sevilla, c/Profesor García González, 1, E41012 Sevilla, Spain * Authors to whom correspondence should be addressed. Polymers 2022, 14(11), 2195; https://doi.org/10.3390/polym14112195 Received: 26 February 2022 / Revised: 9 May 2022 / Accepted: 13 May 2022 / Published: 28 May 2022 (This article belongs to the Special Issue Development of Bio-Based Materials: Synthesis, Characterization and Applications) Downloadkeyboard_arrow_down Browse Figures Review Reports Versions Notes Abstract Zein, a subproduct of the food industry and a protein, possesses limited applications due to its high hydrophobic character. The objective of this research was to investigate the influence of homogenization pressure and cycles on the volumetric mean diameter (D4,3), span values, and Turbiscan Stability Index (TSI) using the response surface methodology for microfluidized emulsions containing zein as a unique stabilizer. Results showed that homogenization pressure seems to be the most influential parameter to obtain enhanced physical stability and droplet size distributions, with the optimum being 20,000 psi. Interestingly, the optimum number of cycles for volumetric diameter, span value, and TSI is not the same. Although a decrease of D4,3 with number of cycles is observed (optimum three cycles), this provokes an increase of span values (optimum one cycle) due to the recoalescence effect. Since physical stability is influenced by D4,3 and span, the minimum for TSI is observed at the middle level of the cycles (2 cycles). This work highlights that not only volumetric diameter, but also span value must be taken into consideration in order to obtain stable zein emulsions. In addition, this study wants to extend the limited knowledge about zein-based emulsions processed with a Microfluidizer device.