Structuring Food Emulsions to Improve Nutrient Delivery During Digestion

Emulsion-based delivery systems can be used to control the release, target the delivery, and inhibit unfavorable chemical reactions of many nutrients. Over the last several years, many attempts have been made to understand the physicochemical changes of food emulsions during digestion and their effects on the delivery of nutrients therein. In vivo and in vitro studies focusing on oral environment or gastrointestinal tract have revealed that food emulsions experience complicated physical and biochemical stresses during digestion. Microstructural changes induced by droplet flocculation, creaming, phase separation, etc., are widely observed during digestion of food emulsions, and the intensity and the locations of the changes that occur greatly affect the delivery efficacy (i.e., bioavailability) of the nutrients. Careful design of emulsion structures provides ways to better control the responses of the emulsions over environmental conditions during digestion and thus improve nutrient delivery. This review summarizes current understanding of emulsion performances during digestion and their effects on nutrient release and digestion. We introduce several novel-structured emulsions, i.e., multilayer emulsions, multiple emulsions, gelled emulsions, Pickering emulsions, and solid lipid particles and their advantageous roles in delivering food nutrients in digestive tract. Examples of nutrient delivery, covering a wide range of food nutrients, including functional lipids, proteins, carotenoids, volatile flavor compounds and minerals, are discussed.