Fabrication, physicochemical properties and structural characteristics of nanoparticles from carrot pomace and its insoluble dietary fiber

Modifying insoluble dietary fiber (IDF) to improve its application has received a growing interest in the food industry. In this study, carrot pomace and extracted IDF nanoparticles (CPNPs and IDFNPs, respectively) were produced in the sequence of milling, homogenization, and ultrasonication which resulted in the breakdown of particles and subsequently, the formation of NPs with sizes of ∼200 nm. The results demonstrated that nanosizing treatment effectively pulverized the particle sizes of CP (279 μm–203 nm). As the particle size decreased, ζ-potential (−17.9 to −22.9 mV), WHC (17.1–19.7%), and OHC (3.7–19.3%) tended to increase significantly (p < 0.05), in which, the highest WHC (21.29 g/g), OHC (25.49 g/g), as well as the absolute value of the ζ-potential (−38.8 mV) and the smallest contact angle (23.795°) were detected for IDFNPs. SEM images also revealed an increment in surface porosity after nanosizing process. However, based on XRD analysis, the crystalline structure of particles was not obviously different, which was confirmed by the results of FTIR spectroscopy. The results revealed carrot pomace NPs could be suitable for typical nanoparticle applications, such as Pickering stabilizers, emulsifiers, thickeners, and even fat replacers.