Effect of soaking conditions on the yield, integrity, and stability of oleosomes from hemp seeds (Cannabis sativa L.)

Oleosomes are natural lipid storage organelles found in plant seeds, comprising a triacylglycerol core encased within a phospholipid-protein monolayer. This study investigated how soaking conditions influence the yield, composition, and oxidative stability of oleosomes extracted from Australian hemp seeds (Cannabis sativa L.). Specifically, three time-temperature combinations (4 °C for 18 h, 25 °C for 8 h, and 60 °C for 2 h) and three buffer pH levels (4.5, 7.0, and 9.0) were studied. All treatments achieved similar seed hydration and oleosome yields (60.1-64.1 %) with the highest yield (64.1 %) recorded for seeds soaked at 4 °C and pH 9.0. However, protein incorporation into the oleosome interface varied substantially (2.6 % to 10.2 %), with the highest levels observed at 60 °C and pH 7.0. These oleosomes also exhibited the greatest oxidative stability (∼80 min), whereas those prepared at 25 °C and pH 7.0 were least stable (∼52 min). Thermal analysis further showed that oleosomes obtained at elevated soaking temperatures displayed elevated transition temperatures and enthalpy of denaturation, indicating enhanced interfacial structural integrity and thermal resilience of the phospholipid-protein monolayer. Overall, these findings indicate that although soaking conditions exert minimal influence on extraction yield, they profoundly affect oleosome interfacial composition and functionality. Optimising soaking conditions can improve the structural and oxidative stability of oleosomes as natural emulsifiers or lipid carriers in food, cosmetic, and nutraceutical formulations.