Study On Emulsification Mechanism Of Garlic Distilled Mother Liquor And Distillate Liquor

Steam distillation is currently the most common method for extracting garlic essential oil in industry.However,a large amount of distillation mother liquor and distillation wastewater remain after distillation.Although these residues contain rich functional components,most of them are discarded,resulting in a waste of resources.The water extract of garlic contains polysaccharides,protein and other components suggesting that the mother liquor of distillation may have emulsification function,but its emulsification ability and emulsification mechanism are still unknown.In addition,the emulsification phenomenon in the distillate formed after distillation is obvious,and the separation of oil and water is difficult,which restricts the development of industrialization of garlic oil distillation and extraction.Based on this,the capacity of mother liquor as emulsifier was studied for the first time.The subcomponents with high emulsification activity were analyzed through classification identification.Finally,the composition structure was changed by proteolysis and polysaccharide acid degradation,and the emulsification mechanism was clarified.In addition,taking the emulsification phenomenon in distillation as the starting point,the process of emulsification to form a dilute emulsion in extraction and the dynamic change of emulsifier content were clarified.The results are beneficial to improve the application value of byproducts from garlic distillation.The main results are as follows:(1)Study on emulsifying components and emulsifying mechanism of garlic distilling mother liquor: In this study,stable garlic oil emulsion(droplet size: 238 nm)was successfully prepared using the ethanol precipitation(EP)of RML as emulsifiers for the first time,and the critical emulsifying components in EP were fractionated and characterized in this study.Ethanol precipitation method was used to determine that the main distribution of emulsified components is in the alcohol precipitation(EP),and the ethanol supernatant(ES),which was mainly composed of small molecules,had no emulsification ability.To further identify the emulsifying components,EP was fractionated to four sub-fractions(EP-1.0,EP-1.5,EP-2.0,and EP-2.5)by gradient ethanol precipitation,then their chemical composition and emulsifying capacity were systematically investigated.It was found that EP-1.5 showed excellent emulsification performance.To further clarify the emulsifying mechanism of EP-1.5,enzymatic deproteinization and acid hydrolysis were used to regulate the protein contents and polysaccharides structure,respectively.Then the influence on emulsifying capacity were studied.On the one hand,the results of this study are helpful to improve the comprehensive utilization of garlic oil distillation by-products,and on the other hand,they are also beneficial to stabilize garlic oil,reduce the irritation of pure garlic oil,and broaden the application range of garlic oil.In addition,it also provides useful inspiration for the development of natural food emulsifiers from plant by-products.(2)Analysis and application of emulsification law in garlic distillate: This study took the emulsification phenomenon in the garlic oil distillation process as the starting point,and proved for the first time that the distillate in the 0.5-2.5 h period can spontaneously form a stable natural dilute emulsion;Secondly,taking the distillate as the research object,the dynamic changes of the components in the distillate at different extraction periods were studied,it was revealed that 1,3-dithiane and 5-methyl-2-thiophenecarbaldehyde are the main causes of emulsification during garlic distillation.In addition,the antioxidant activity of the dilute emulsion was also studied,and the efficacy value of the by-products was confirmed.The results of this study not only provide a research basis for intervening such emulsifying components in the later stage and controlling the occurrence of emulsifying phenomenon,but also provide scientific support for the comprehensive utilization and application value improvement of garlic distillation by-products.The research results of this topic contribute to the deep processing of garlic essential oil distillation byproducts,point out the direction to solve the emulsification and oil-water separation problems in garlic essential oil distillation,and ultimately provide a theoretical basis for the comprehensive utilization of garlic distillation by-products and the improvement of their application value.