The Effects of Dairy and Plant-Based Liquid Components on Lutein Liberation in Spinach Smoothies

Lutein is a dietary lipophilic compound with anti-inflammatory properties. We havepreviously shown that dairy fat can improve the lutein content in spinach smoothies. It is, however,unclear whether fat concentrations and fermentation status in dairy products affect lutein liberation insmoothies. Moreover, plant-based milks vary in fat, protein, and fiber content which may affect luteindissolution. This study aimed to provide translatable information to consumers by comparing luteinliberation in spinach smoothies made with different dairy or plant-based liquids in domestic settings.The smoothies were digested in vitro, and liberated lutein was measured by high-performance liquidchromatography (HPLC). High-fat and medium-fat cow’s milk, as well as coconut milk with andwithout additives, were found to significantly improve lutein liberation by 36%, 30%, 25%, and 42%,respectively, compared to blending spinach with water alone. Adjustment models suggested thatthe effects of cow’s milk and coconut milk were derived from fat and protein, respectively. On theother hand, soymilk with and without additives showed significantly reduced lutein liberation by40% and 61%, respectively. To summarize, only 4 out of 14 tested liquids increased lutein liberationin spinach smoothies. The results highlight the importance of testing food companions for lipophilicactive ingredients.Funding: Heart-Lung Foundation, Sweden [20180436]; Swedish Research Council [2018-03232]