Abstract: This study aimed to explore the effects of catechins, resveratrol and gallic acid on the physicochemical stability and digestive properties of soybean oil bodies. The results showed that catechin and resveratrol significantly reduced the average particle size of oil bodies (P < 0.05), while gallic acid had a small effect on it. The average particle size of oil bodies was decreased from (15.29 ± 0.28) to (0.73 ± 0.06) and (7.42 ± 0.27) μm by adding catechin and resveratrol at 30 μmol/L, respectively. Low concentration of gallic acid and high concentration of resveratrol significantly reduced the absolute value of the ζ-potential of oil bodies (P < 0.05), and the ζ-potential was changed from –(21.80 ± 0.08) to –(17.60 ± 0.57) mV by adding 30 μmol/L of gallic acid, while catechin and low concentrations of resveratrol had no significant effect on the ζ-potential of oil bodies (P > 0.05). The emulsifying activity index (EAI) and emulsion stability index (ESI) were increased by all three phenolic compounds except that high concentration of catechin had no significant effect on the emulsifying properties (P > 0.05). The EAI and ESI of the oil body containing 50 μmol/L of resveratrol increased from (20.44 ± 0.18) m2/g and (102.97 ± 3.32) min to (21.19 ± 0.03) m2/g and (177.56 ± 7.89) min compared to the control group without resveratrol, respectively. The surface hydrophobicity was significantly increased by these three phenolic compounds (P < 0.05), and the oxidation stability was also improved to different degrees. All three phenolic compounds could delay the in vitro digestion of oil bodies. Catechin, resveratrol and gallic acid at a concentration of 500 μmol/L could decrease the release of free fatty acids by 22.9%, 18.1% and 10.7%, respectively, when simulated intestinal digestion for 120 min. From these results, we concluded that these three phenolic compounds could improve the physicochemical stability of soybean oil bodies and reduce the rate of lipid digestion during gastrointestinal digestion. Our findings may provide a theoretical reference for improving the quality of soybean oil body-related products.

Key words: oil body; catechins; resveratrol; gallic acid; stability