In recent years, virgin coconut oil (VCO) has been gaining dramatic growth in food markets and is one the most clinically studied edible oils. However, owing to its low plasticity and stiff nature, VCO could not be applied directly in edible fats production and various modification processes must be considered. In present study, physical blending with palm olein (PO) and chemical interesterification were conducted in order to improve the functional characteristics of VCO. Likewise, the alterations in chemical composition, solid fat content (SFC), slip melting point (SMP) and rheological attributes (e.g. flow behavior, strain sweep, frequency sweep and temperature sweep) of fat blends, prior and following interesterification were investigated. All blends were trans-free and interesterification modified the melting characteristics of fat blends through reduction of SFC and SMP. In terms of rheological attributes, a shear thinning demeanor in all fat blends was noticed and the flow data were fitted well with Herschel-Bulkley model. Interesterified samples were illustrated lower storage (G′) and loss (G″) moduli compared to initial blends.

Sage leaf extract (SLE) is considered an excellent source of bioactive compounds mainly because of its high content of phenolics, widely known as natural antioxidants.This study aimed to compare the performance of free/encapsulated SLE by different coatings in protecting sunflower oil against oxidative deterioration. The coating materials were whey protein isolate and qodumeh seed gum at different ratios (1:0, 1:1, and 0:1). Each nanocapsule was analyzed for particle size, zeta potential, encapsulation efficiency, phenolics release, and SEM images. The total phenolic compounds of SLE were 31.12 mg GA/g. The antioxidant activity of SLE was increased in both DPPH and FRAP assays by increasing extract concentration from 50 to 250 ppm. All nanoparticles exhibited nanometric size, negative zeta potential, encapsulation efficiency higher than 60%, and gradual release during storage. The oxidative stability of sunflower oil with or without the incorporation of 250 ppm of free/encapsulated SLE was evaluated during 24 days of storage at 60°C. Peroxide value (PV), thiobarbituric acid value (TBA), oxidative stability index (OSI), color index (CI), and conjugated dienes (CD) were determined. COPM nanoparticles showed the lowest PV, TBA, CI, and CD but both SGUM and WHEY were more effective in delaying oil oxidation than TBHQ and free extract. Higher OSI was observed in oil-containing nanoparticles with composite coating. Results obtained reinforce the use of whey protein isolate and qodumeh seed gum as a coating for encapsulating SLE to increase the shelf life of sunflower oil as a natural antioxidant.