Unveiling the relationship between the oil binding capacity and physical properties in inter-esterified soybean and palm-based fats

Abstract: High oil binding capacity (OBC) is critical in reducing oil migration from occurring in fat-based food and is especially challenging due to the FDA removing the GRAS status of partially hydrogenated oils and recent nutritional recommendations to reduce the consumption of saturated fat. Therefore, the objective of this study was to identify the physical properties of two fats – an interesterified soybean-based fat (EIESOY) and an interesterified palm-based fat (EIEPO) that correlates with high OBC. In this study, three concentrations of these fats were tested to understand how the saturation level impacted OBC – a 100% sample (non-diluted sample), a 50% sample (diluted 50% with soybean oil w/w), and a 20% sample (diluted 80% with soybean oil w/w). In addition to different dilutions, the samples were also processed using fast (10 °C/min) and slow (0.1 °C/min) cooling rates as well as with and without high-intensity ultrasound (HIU, 20kHz) to further manipulate the physical properties. Samples were crystallized between 32.5 °C and 20 °C and HIU was applied to samples at the onset of crystallization. All samples were allowed to crystallize isothermally for 90 min. After the isothermal crystallization physical properties including crystal morphology, hardness, solid fat content (SFC), elasticity melting behavior, and OBC using a centrifuge method (OBC_c) were evaluated. Samples were then stored at 22 °C and 5 °C for 48 h and at which point the same physical properties were measured again with the addition of an OBC measurement using a filter paper method (OBC_p). Results show that in the soybean-based fat, both OBC_c and OBC_p were positively correlated with SFC, G’, G’’, Tpeak, enthalpy, and hardness (p < 0.05 for all correlations). In the palm-based fat, both OBC_c and OBC_p were positively correlated with SFC, G’, hardness, and enthalpy and negatively correlated with δ (p < 0.05).