Pulsed electric fields technology enhances the functionality of orange by-products: A study on dietary fiber fractions and structure

Orange juice industrial wastes, such as peels (OP) and bagasse (OB), are cost-effective sources of dietary fiber (DF). However, their high insoluble DF (IDF) content limits their use in food formulations due to poor techno-functionality. While thermal and chemical methods have traditionally been used to transform IDF into soluble DF (SDF), innovative physical treatments remain less explored to modify DF fractions. This study evaluated the effects of pulsed electric fields (PEF) on the DF fractions and techno-functionality of OB and OP. Additionally, it aimed to gain insight into the structural changes induced by PEF. PEF promoted the partial solubilization of IDF polysaccharides, attaining maximum SDF levels of 11.9 % and 9.5 % at specific energy inputs (W) of 5.63 and 18.58 kJ/kg for OB and OP, respectively. OB was more susceptible to PEF, requiring lower W to yield higher SDF contents. Overall, PEF improved the hydration properties of both by-products, increasing up to 65 % compared to untreated counterparts. Microstructural analysis revealed that PEF transformed compact OB and OP matrices into open networks with increased surface area, enhancing their water-holding capacity. FT-IR analysis suggested that PEF destabilized non-covalent interactions, facilitating IDF solubilization. DSC thermograms revealed greater thermal stability in PEF-treated by-products, likely due to increased SDF-water interactions. Moreover, PEF increased the extractability of polyphenols in both by-products, improving their potential as functional ingredients. In conclusion, this study showed that processing orange by-products by PEF could be a promising physical strategy for developing DF-rich ingredients with enhanced SDF-to-IDF ratios and functionality.