Effect of food preparation on the structure and metabolic responses to a monostearin–oil–water gel-based spread

Widespread recognition of the negative health effects of trans and saturated fats has prompted research to develop alternative structures that can structure liquid oils into semi-solid plastic pastes for food applications. We have recently developed and described the physical chemical properties of a unique a monostearin–oil–water gel (MAG) that achieves this goal. Furthermore, ingestion of this MAG in the form of a margarine-like spread resulted in beneficial suppression of blood lipid and insulin responses in humans compared to compositionally-equivalent controls lacking the MAG structure. However, the integrity of this novel structure and its salubrious metabolic effects have not been previously evaluated under food processing conditions. The purpose of the current study was to evaluate the integrity of the MAG when applied to toasted bread and when mixed with a warm pasta meal, and to evaluate the metabolic effects over 6 h following ingestion of both types of meals with MAG compared to compositionally-equivalent unstructured oil preparations. MAG structure was maintained in the toast study, but the pasta meal destroyed the MAG structure. Triglyceride, free fatty acid, and insulin responses were suppressed in the MAG trial compared to the unstructured oil trial of the toast study, whereas there was no difference in the responses of these variables between the two trials in the pasta study. The results demonstrate for the first time that the metabolic effects of MAG depend on maintenance of the MAG structural integrity throughout the food processing procedures leading up to ingestion. Thus, this study demonstrates the utility of MAG as a trans- and saturated fat-free vehicle to structure and deliver liquid oil as a semi-solid plastic paste, and establishes processing limits to the integrity of the additional beneficial metabolic effects of this novel structure.