Controlled Release Of Flavor Substances From Sesame Oil By Gelation

Sesame oil,a traditional vegetable oil used for seasoning in China,has a strong and unique flavour and is rich in nutrients.However,the oxidative rancidity of fats and the uncontrollable volatile release of flavour substances in sesame oil will decrease the quality of sesame oil and lose its flavour characteristics.Therefore,improving the storage stability and achieving flavour controlled release of sesame oil are keys to the modernization of sesame oil.The solidification of vegetable oil supramolecular gels can form a controlled release of volatiles.However,at present,the mechanism of controlled release between the self-assembly behavior of oleogel and the small molecules of sesame oil flavour is not clear.Based on this,this paper explores the influence of gelation on the release of flavour substances from sesame oil by preparing wax ester and monoglyceride oleogels,and also analyzes the physicochemical properties,microcrystalline structure characteristics,molecular interaction mechanism and storage stability of the oleogels.The aim of this paper is to establishing controllable flavour delivery systems for maintaining the nutritional value and flavour of sesame oil.The main findings are as follows:(1)The characteristic volatile flavour substances of sesame oil were identified.Through the optimization of extraction and detection conditions,the most optimal SPME-GC/MS experimental conditions were selected,and the analysis revealed that the compounds with higher contents in the sesame oil samples were pyrazines,furans,pyrroles,phenols,aldehydes,alcohols and Hydrocarbons.The main volatile components of sesame oil produced by different processing techniques were determined by the ROAV method.Among them,the main volatile components of water extraction and hot-pressed sesame oil(ROAV≥1)were roughly the same,which are Methyl furfuryl disulfide,2,3-Diethyl-5-methylpyrazine,2-Methoxy-Phenol,2-Acetyl-3,4,5,6-tetrahydropyridine,4-Hydroxy-2,5-dimethyl-3(2H)furanone,2-Ethyl-3,5-dimethylpyrazine,Acetylpyrazine,2-Pentylpyridine,3-Ethyl-2,5-dimethylpyrazine,(E)-2-Octenal,2-Heptenal and 2-Acetyl-3-methylpyrazine.There are 8 main volatile components of cold pressed sesame oil,including(E)-2-Octenal,2-Heptenal,Hexanal,(Z)-β-Ocimene,1-Octanol,2-Pentylfuran,1-Hexanol and 2-Acetyl-6-methylpyrazine.(2)The physicochemical properties,microcrystalline structure characteristics and molecular interaction mechanism of sesame oil supramolecular gel were studied.The results show,with the strongest gelation ability,CLW and BW exhibit high oil holding capacity,and high textural and thermodynamic parameters(enthalpy change).The characteristic diffraction peaks of wax-based oleogels and GMS oleogel correspond toβ′ and α crystal forms,respectively,and the microstructure of oleogel formed by different gel factors is quite different,but in all oleogel samples no characteristic peaks of hydrogen bonds or chemical intermolecular interactions were observed in the infrared spectra,indicating that only physical interactions occurred among the components of the oleogel.In addition,the results of oxidation induction time show that,the oxidation stability of all oleogels,except RBW oleogel,was higher than that of sesame oil.(3)The transfer and release pattern of flavour small molecules in oleogel and the storage stability of sesame oleogels were explored.The results show that the gel solidification can achieve the controlled release of flavour substances in sesame oil,and the retention effect is more significant for compounds with higher saturated vapour pressure or hydrophilic compounds.During the course of storage,the release of small flavour molecules of sesame oil can be described by the weibull equation kinetic model.As the gel system with the best flavour control release effect,BW oleogel has good retention effect for flavour molecules with different physicochemical properties.Pearson correlation analysis of the physical properties and flavour release behavior of oleogel founds that the loss rate of flavour substances is mainly affected by the hardness and viscosity of oleogel.The results of the storage stability study show that,with the exception of RBW oleogel,all other oleogel samples have a longer product shelf life than sesame oil.