Polar Lipids Reduce In Vitro Duodenal Lipolysis Rate of Oat Oil and Liquid Oat Base Products

Abstract

Alternative ways for increased appetite control are today widely sought for due to the growing global health issues connected to obesity. In in vivo studies, oat has been proven an attractive candidate for inducing satiety. Oat is rich in polar lipids, of which the galactolipids are especially interesting, and a hypothesis is that these lipids play an important role for the ileal brake mechanism. In this study, the aim is to investigate the role of polar oat lipids on pancreatic lipolysis rate, using a pH‐stat based in vitro digestion model of the duodenum. Lipolysis of oat oil, a mix of oat oil/rapeseed oil (RSO), as well as a liquid oat base (OB) simulating an oat drink with different polar lipid content are investigated, and compared with RSO as control. Increasing the polar lipid content of the product digested leads to a significantly decreased lipolysis rate, and this effect is even observed when mixing RSO with a low amount of oat oil (10%). The results support the hypothesis that polar lipids can delay lipolysis also in a complex, natural system like the liquid OB, and even a minor amount of oat lipids can have large effect on lipolysis rates. Practical applications: The number of studies connecting galactolipids with a decreasing effect on duodenal lipolysis is growing; however, the mechanism behind this phenomenon is still not clarified. Here, the same effect is seen in a complex, natural food system. These findings open up for interesting future food products, where inclusion of oat oil, even at low concentrations, can have a prolonging effect on satiety. Oat for human consumption is an increasing market, thanks to the positive health benefits oat has been connected to, in combination with the current trend toward climate‐friendly plant‐based options for meat and dairy products. It is believed that oat oil can be attractive as an ingredient in various food products, for example, protein bars and spreads. More studies are needed to confirm the results in vivo. However, a great potential is seen for the use of oat oil to enhance appetite control.

Oat Polar Lipids Improve Cardiometabolic-Related Markers after Breakfast and a Subsequent Standardized Lunch: A Randomized Crossover Study in Healthy Young Adults

“…One possible underlying mechanism behind the increased concentrations of gut hormones relates to slower hydrolysis or limited digestion of oat polar lipids compared to e.g., rapeseed triglycerides, resulting in a delayed absorption, and thus potentially increased stimulation of gut hormones release (GLP-1 and PYY) throughout the gastrointestinal tract. Such a hypothetical mechanism was already suggested by Ohlsson et al [19], and is supported by observations showing delayed enzymatic hydrolysis of polar lipids from oat and other sources in in vitro models [33,34]. GIP was another gut hormone investigated.…”

Inclusion of Oat Polar Lipids in a Solid Breakfast Improves Glucose Tolerance, Triglyceridemia, and Gut Hormone Responses Postprandially and after a Standardized Second Meal: A Randomized Crossover Study in Healthy Subjects

“…In the human intestine, the digestion of galactolipids is carried out by pancreatic lipase-related protein 2 (PLRP2) [26]. However, the delayed hydrolysis of polar lipids by pancreatin has been observed in vitro, suggesting a similar effect in vivo [27]. This may lead to delayed absorption, which could potentially result in an enhanced release of GLP-1 and PYY.…”

Chemical Characterisation of New Oils Extracted from Cañihua and Tarwi Seeds with Different Organic Solvents

“…The composition of the mobile phase was 66% n-heptane, 33% diethyl ether, and 1% acetic acid (v/v) for the neutral lipids and 85% chloroform, 15% methanol, 10% acetic acid, and 3.5% water (v/v) for the polar lipids. To detect the separated lipid classes, primulin in acetone:water (8:2, v/v) staining solution was utilised [18,19].…”