Dietary intake of excess trans fatty acids and to a lesser extent, excess saturated fatty acids along with insufficient n-6 polyunsaturated fatty acids, has been estimated to increase coronary heart disease (CHD) mortality worldwide. Over the years, almost entire removal of hardstock trans fats has been achieved; whereas full substitution of hardstock long-chain saturated fatty acids (e.g. palmitic acid) by unsaturated fatty acids (i.e. liquid oil) has proven elusive. Substitution of saturated fats brings unprecedented industrial challenges, as their removal affects adversely physical properties, functionality, stability and sensory attributes of oil-based suspensions, leading to food products poor in quality and consumer acceptability. Furthermore, in addition to address the technological challenges brought about by the subsitution of saturated fats, it is desirable that any oil-structuring alternative to be “clean label” or free of additives, to boost their acceptability and commercialization. Currently, there are limited commercially-viable strategies to formulate healthier fats within the field of gelled oils or oleogels. None of the current ‘oleogel’ are suitable for food applications as they do only meet partially the following criteria: 1) being food grade, natural, 2) complement physical characteristics of fats such as temperature induced melting, 3) mimic or complement the rheology and texture of solid saturated lipids. Besides this criteria, it is of paramount important to establish links between the mesoscopic structure and mechanics of the developed oleogel systems. To address this grand industrial and fundamental challenge, we proposed to design novel hybrid ‘oleogels’ using a biomimetic approach based on edible plant particles along with economical solid fat sources, and understand the underlying structure, physical properties, and texture. To achieve this goal, we specifically met the following objectives: (1) Developed oil continuous colloidal gels and colloidal glasses based on individual/binary mixtures of plant derived edible colloidal nanoscale particles, (2) Developed new hybrid systems: bicontinuous glass-gel networks and bicontinuous gel networks, comprising individual/binary mixtures of colloidal particles along with the fat particles to introduce temperature melting and (3) Established structure and rheology relationships in (1) and (2), and (4) Extended findings from specific goals 1-3, to develop commercially-viable hybrid oleogel systems. Overall, we arrived to the following conclusions: 1) the mechanics of model suspensions of glass-gel and gel-gel comprising starch or micro fibrillated cellulose, and lipid particles can be closely described by phenomenological models for particle-filled yield stress fluids, and micromechanical models proposed for interpenetrating multiphase composites, 2) the mechanics of the previously mentioned systems depend on two main observables: total volume fraction, and mixture composition or the relative concentrations of colloidal species, 3) Bonding and caging mechanics, dependent on the observables, define static structures and dynamic properties and 4) The model glass-gel and gel-gel oil-continuous soft materials can be realized with commercially-relevant food-grade ingredients.
