Oil binding capacity of edible fats: What is new?

Abstract: Oil binding capacity (OBC) can be defined as the ability of a fat crystalline network to entrap oil and is an important property in semisolid fats because it might limit their use in various applications. OBC is especially vital for healthy fats that have no trans-fatty acids and have low levels of saturated fatty acids as they typically have low OBC and limited shelf-life.

Previous studies have evaluated the OBC of various fats with several contradicting results. For example, some studies showed that OBC is driven by the size of the crystals, hardness, solid fat content (SFC), or by a combination of these factors. However, it is difficult to pinpoint which physical properties truly drive OBC.

The aim of this presentation is to summarize some of the latest research in our laboratory that explores the impact of various physical properties on OBC. Experiments were designed to obtain a wide range of physical properties and OBC values. Results show that OBC is mainly driven by solid fat content and viscoelastic properties of the fat crystalline network. In this presentation we will show that high OBC values (close to 100%) are obtained in samples with high viscoelastic properties (elastic modulus between 10⁵ and 10⁶ Pa and viscous modulus between 10⁴ and 10⁵ Pa), high hardness (between 30 and 60 N), and high SFC (approximately 60%). However, high OBC values can also be obtained in fats with lower SFC values (less than 30%), lower elasticity (10⁴ Pa) and low hardness (less than 10 N) when small crystals (around 10 mm) are present. Even though our research did not find any linear correlation between OBC and crystal size, results suggest that smaller crystals can help retain oil in a weak crystalline network demonstrating that a more complex model may be needed to predict OBC.