Emulgels Structured with Dietary Fiber for Food Uses: A Rheological Model

Emulgels are biphasic emulsified systems in which the continuous phase is structured with a specific gelling agent. In this work, a rheological and microscopic investigation of O/W emulgels prepared by structuring the aqueous (continuous) phase with citrus fiber was carried out with the aim of designing their macroscopic properties for food uses and predicting their characteristics with a rheological model. According to previous investigations, fiber suspensions behave as “particle gels” and, consequently, the derived emulgels’ properties are strongly dependent on the fiber concentration and on process conditions adopted to produce them. Therefore, a rotor–stator system was used to prepare emulgels with increasing fiber content and with different levels of energy and power used for mixing delivered to the materials. An investigation of particle gels was then carried out, fixing the operating process conditions according to emulgel results. Furthermore, the effect of the dispersed (oil) phase volume fraction was varied and a modified semi-empirical Palierne model was proposed with the aim of optimizing a correlation between rheological properties and formulation parameters, fixing the process conditions.