A comparative study of mayonnaise and Italian dressing prepared with lipase-catalyzed transesterified olive oil and caprylic acid

Viscoelastic properties of mayonnaise and Italian salad dressing prepared w ith olive oil and enzymatically synthesized structured lipid (SL) from capr ylic acid and olive oil were studied using an SR5000 dynamic stress rheomet er. Storage modulus (G ') and loss modulus (G ") were determined as functio ns of frequency, temperature, and stress. Frequency sweeps did not show sig nificant differences between dressings prepared with olive oil or SL. For a ll mechanical spectra, G ' values were consistently higher than G " values. Both Italian dressing and mayonnaise samples displayed similar gel-like ch aracteristics. Mayonnaise and Italian dressings made with olive oil separat ed when they were brought to room temperature from refrigeration temperatur es. SL-based mayonnaise did not separate. Only minor separation was observe d in SL-based Italian dressing. A change in the crystallization properties of the two oils was probably responsible for the differences observed after refrigeration. Both SL-based and unmodified olive oil-based mayonnaise and Italian dressing samples had similar viscoelastic character.