Influence of polar compounds distribution in deep‐frying oil on lipid digestion behaviour

Summary Deep‐frying oil featuring total polar compound (TPC) has been found to be unhealthy. However, little information is available regarding the impact of TPC on the lipid digestion behaviour. In this study, three typical edible oils (palm oil, PO; high oleic acid peanut oil, HOA; and high linoleic acid sunflower oil, HLA) were selected to investigate the effect of deep‐frying on the lipid digestion. Digestion behaviour was monitored by pH‐Stat method in vitro. Digestibility rate analysis showed that free fatty acids release rate of all TPC groups was the slowest among corresponding fresh oils and deep‐frying oils, indicating deep‐frying decreased lipid digestion rate. Lipid droplet analysis uncovered that deep‐frying could increase lipid particle size. Correlation analysis showed the polymers in TPC are negatively correlated with digestion rate and particle size, suggesting the digestion behaviour of deep‐frying oil is related to TPC constitution. In conclusion, this study highlights that deep‐frying weaken the lipid digestion capacity, and the multiplicity of TPC distribution which vary in terms of FAs type contribute to differences of digestion behaviour in deep‐frying oils. Deep‐frying changes the lipid digestion behaviors.