Effect of Dietary Fiber and Thermal Conditions on Rice Bran Wax-Based Structured Edible Oils

Abstract

In this work, extra-virgin olive oil (EVO)- and sunflower oil (SFO)-based oleogels were structured using rice bran wax (RBW) at 10% by weight (w/w). Bamboo fiber milled with 40 (BF40), 90 (BF90) and 150 (BF150) µm of average size was added as a structuring agent. The effect of fiber addition and cooling temperature (0, 4, and 25 °C) on thermal and structural parameters of achieved gels was assessed by rheological (both in rotational and oscillatory mode), texture, and differential scanning calorimetry tests. Oleogelation modified the rheological behavior of EVO and SFO, thus shifting from a Newtonian trend typical of oils to a pseudoplastic non-Newtonian behavior in gels. Moreover, oleogels behaved as solid-like systems with G′ > G″, regardless of the applied condition. All samples exhibit a thermal-reversible behavior, even though the presence of hysteresis suggests a partial reduction in structural properties under stress. Decreasing in cooling temperature negatively contributed to network formation, despite being partially recovered by low-granulometry fiber addition. The latter dramatically improved either textural, rheological, or stability parameters of gels, as compared with only edible oil-based systems. Finally, wax/gel compatibility affected the crystallization enthalpy and final product stability (gel strength) due to different gelator–gelator and gelator–solvent interactions.

A Potentially Ecosustainable Hazelnut/Carob-Based Spread

“…Total dietary fiber and its fractions (soluble and insoluble ones) were determined using a K-TDFR-200A Kit (Megazyme, Wicklow, Ireland) based on the AOAC method 991.43 as reported by [ 23 ].…”

“…The rheological behavior of all spreads was analyzed in either static (rotational) or dynamic (oscillatory) conditions. The applied methods were the same as reported in [ 23 ] with slight modifications.…”

“…As reported in [23], a tribocell equipped with a stainless-steel ball-on-three-PDMSplate geometry was used to evaluate the friction coefficient of the spread at 36.5 °C (the average oral cavity temperature). Before the analysis, each sample was maintained and International Journal of Food Science equilibrated at 36.5 °C for 1 hour to achieve a homogenous temperature in the spread.…”