Interaction Analysis Of β-cyclodextrin And Its Derivatives With Cholesterol And Its Application In The Removal Of Cholesterol From Tallow

β-Cyclodextrin(β-CD)is often used to remove cholesterol in food systems.In the process of removing cholesterol,the embedding reaction of β-CD is typically required to promote by raising the reaction temperature due to its poor water solubility.However,the excessive reaction temperature adverse to the complexation of β-CD with cholesterol,which restricts its application in food.It is crucial to explore the stability regulation mechanism of cholesterol/β-CD inclusion complex at the molecular level.In this study,experimental and theoretical approaches were used to examine the interaction mechanism of β-CD and its derivatives with cholesterol,and the effects of β-CD derivatives modified with different substituents on complexing with cholesterol.Furthermore,the impact of hydroxypropyl-β-cyclodextrin(HP-β-CD)on the cholesterol removal of tallow and its quality of before and after removing cholesterol were evaluated.The main results were as follows:(1)The complexation behavior and thermodynamic properties of cholesterol/β-CD inclusion complex were analyzed by experimental techniques,and conformation search and density functional theory were combined to explore the interaction between cholesterol and β-CD.Phase solubility studies suggested the formation of 1:1stoichiometric inclusion complex of cholesterol with β-CD.The inclusion complex showed higher decomposed temperature(327.3 ℃)than physical mixture(321.6 ℃),indicating improved thermal stability of inclusion complex.Theoretical calculations were performed to obtain the most stable conformation with the lowest complexation energy(-129.66 kJ/mol).The results of interaction analysis showed that van der Waals and hydrogen bonds were necessary to drive spontaneous formation and maintain the stability of inclusion complex.Dispersion energy from van der Waals(-283.31 kJ/mol)contributed greatly on complexation energy(-204.72 kJ/mol),forming the moderate intermolecular hydrogen bonds(O127×××H221 and O220×××H107).This study revealed a deep insight into the formation mechanism of cholesterol/β-CD inclusion complex using computational and experimental approaches,providing theoretical basis for the removal of cholesterol from food systems.(2)The effects of β-CD derivatives on the complexation properties and stability mechanism were further investigated by experimental and theoretical methods.Phase solubility studies suggested the formation of 1:1 stoichiometric inclusion complex of cholesterol with β-CD and its derivatives.Thermogravimetric analyses and infrared spectra showed that the complexes between cholesterol and β-CD derivatives were formed through van der Waals forces,hydrogen bonds and other interactions and improved their thermal stability.The results of proton nuclear magnetic resonance spectroscopy confirmed the reasonable geometric structure of the β-CD derivatives.The binding energy of the complexes was calculated by conformational search and density functional theory,suggesting that HP-β-CD had the strongest binding affinity with cholesterol.The results of interaction analyses showed that the complexes formation of β-CD derivatives and cholesterol was mainly via strengthening van der Waals forces and hydrogen bond interaction in the intermolecular interactions.This study elucidated the molecular mechanism of the binding of β-CD derivatives with different substituents to cholesterol at the molecular level,which is expected to provide a theoretical basis for the selection of suitable β-CD derivatives carriers for removing cholesterol.(3)HP-β-CD was used to remove cholesterol from tallow.The cholesterol removal rate was utilized as the index,the effects of addition,stirring time and reaction temperature on the cholesterol removal were investigated.Furthermore,the effects on basic physicochemical indexes,rheological properties and fatty acid composition of tallow after removing cholesterol were assessed.The single factor and orthogonal tests showed that compared with β-CD,the cholesterol removal rate(51.39±0.74%)of HP-β-CD was effectively increased by 9.06%,the optimum reaction temperature was increased from 45 °C to 55 °C,and the optimum reaction time was shortened by 0.5 h.After HP-β-CD treatment,there was less effect on the fatty acid composition of tallow and its acid value,hardness and viscosity value decreased,effectively improved the quality of tallow.The study provided a favorable reference for developing lowcholesterol tallow products.