Properties of oleogels from upcycled oils and extra virgin olive oil
Zhiyi Lin, Eduarda M. Cabral, Carlos Álvarez, Simona Grasso
Abstract
This study explores the use of upcycled oils-pumpkin seed oil (PSO), rice bran oil (RBO), and grapeseed oil (GSO)-sourced from food co/by-products, compared to extra virgin olive oil (EVOO), to formulate novel oleogels, aiming to address the growing demand for sustainable fat alternatives in food applications. Carnauba wax was used as the structuring agent at various concentrations (7%, 9%, and 11% w/w ). The physicochemical and rheological properties of the oleogels were comprehensively evaluated. Results showed that EVOO had the highest monounsaturated fatty acid content (70.99%), and GSO exhibited the greatest polyunsaturated fatty acids at 57.34%. The 11% EVOO oleogels were significantly the lightest (L∗=49.59) and most yellow (b∗=22.34). The 7% PSO oleogels appeared the reddest (a∗=2.42), and the 11% GSO oleogels showed greener hues (a∗=-5.55). Wax concentration significantly influenced textural properties, with firmness increasing from 113.99 g to 804.85 g in PSO oleogels as wax content increased from 7% to 11%. Viscoelastic characteristics also changed accordingly. Notably, GSO oleogels demonstrated superior gel network integrity. Thermal analysis showed that all oleogels had similar melting points of around 76–79 °C. PSO oleogels exhibited relatively high conjugated diene (CD) (values ranging from 24 to 42 μmol/L) and the lowest thiobarbituric acid reactive substances (TBARS) value, between 0.22 and 0.81 mg MDA/kg over 21 days. This study highlights the potential of upcycled oils to create functional oleogels, offering a sustainable alternative to traditional solid fats for various food applications while contributing to the valorization of food co/by-products. • Oleogels with 7–11 % carnauba wax were made using three upcycled oils and EVOO. • Higher wax content (7 %–11 %) increased firmness and G’ (from ∼10 3 to 10 6 Pa) of oleogels. • GSO oleogels showed superior gel integrity and texture. • Upcycled oils are promising for sustainable oleogel-based food systems.