ADHESION OF EDIBLE OILS TO FOOD CONTACT SURFACES

Adhesion of oils and fatty food products to packages is an important s torage problem, because it increases product-package interactions that alter quality. Reducing such adhesion would also allow savings in rec ycling and cleaning processes. The aim of our work was to test if some thermodynamical adhesion models were correlated to edible oils' bulk adhesion as measured experimentally. Food-contact surfaces were low-de nsity polyethylene, polyethylene teraphthalate, stainless steel, and g lass. The Young-Dupre equation and five models of adhesion from the li terature were used to calculate solids' surface tension and the thermo dynamical work of adhesion (Wa). The dispersive, polar, acid-base, and hydrogen surface tension components of oils and solids were calculate d. The experimental adhesion, or amount of edible oils remaining on so lid surfaces after contact, was found to be correlated to Young-Dupre Wa, involving contact angle measured by specially designed image analy sis technique. Two models, involving, respectively, surface tension's hydrogen component and a linear dependence of Wa(p) on the liquid pola r surface tension component, fitted best with oil bulk adhesion as mea sured experimentally. Our theoretical approach to fatty food material adhesion seems, so far, consistent to predict. global residues of edib le oils on solid surfaces.