The Effect Of The Roasting Process And Extraction Method On The Quality Of Coffee Oil Was Investigated

Roasted coffee oil has received much attention because of its characteristic coffee aroma.Oil is one of the most important components of roasted coffee beans and is considered to be an important carrier of roasted aroma and flavor.The volatile compounds in coffee can vary depending on the growing location,climatic conditions,plant species,etc.,and especially the degree of roasting of the beans,which can have a huge impact on the aroma of the coffee oils.Acylglycerol is the main component of coffee oils(80%),followed by unsaponifiable compounds such as diterpenoids,sterols,and tocopherols(15-18%);free fatty acids(0.5-4.2%),and hundreds of volatile compounds.As coffee beans undergo high temperature and long time roasting during the roasting process,a series of physicochemical reactions will occur in coffee beans under high temperature and aerobic conditions,including a series of chemical reactions such as merad,thermal degradation,lipid oxidation,which bring special nutty and roasted aroma to the oil,thus affecting the sensory quality of the oil,and the effect of roasting treatment on the fatty acid composition and volatile components of coffee oil is still unclear.The current extraction methods for coffee oil from roasted beans are relatively single and have various problems;meanwhile,the lipid composition of coffee oil has not been extensively studied.In this paper,Yunnan small-grain coffee beans were roasted at different levels,and the yield,physicochemical properties,color,odor,transparencymead,and fatty acid composition of coffee oil were determined under various conditions;in addition,the contents and composition of the active ingredients,tocopherols,diter,penes and total phenols,were determined byperformance meancemead,,liquid chromatograpfontanelintanol method.The results showed that as the roasting degree was increased,the acid value of coffee oil increased,while the iodine and saponification values decreased;the results of sensory quality measurement showed that as the roasting degree was increased,the color of coffee oil became darker;when the roasting degree was lighter,the smell was lighter,and the color was brighter and clarified,and when the roasting degree was deeper,the oil was darker.Eight saturated fatty acids,including tetradecanoic acid,pentadecanoic acid,hexadecanoic acid(palmitic acid),and octadecanoic acid(stearic acid),accounted for 24.27-42.85%of the total fatty acids found;and three unsaturated fatty acids,oleic acid,linoleic acid,and α-linolenic acid,accounting for 57.78-74.02%.Different roasting conditions had little effect on the fatty acid composition of coffee oil.A total of 94 volatile substances were detected by GC-MS through the volatile composition of coffee oil with 8 different roasting degrees.Different roasting degrees cause variances in the volatile components of coffee,which give coffee oils different scents;the total phenolic content of coffee oil tends to increase a with roasting degree,and the total phenolic content of coffee oil varies greatly among the eight roasting degrees.The presence of natural active ingredients such as kahweol,cafestol,total phenols,and tocopherols in coffee oil,which have anti-inflammatory,anti-inflammatory,and anti-tumor effects,makes it potential to be developed into functional health products.It can also provide theoretical basis and technical support for coffee roasting and processing process improvement and product development.Different EE,UE,ME,and UME treatments were used to extract coffee oil.The scanning electron microscopy results showed that all four treatments broke the apparent structure of coffee powder to different degrees,and its enzymatic treatment made the surface of coffee powder particles with uneven folded structure,and the enzymatic treatment and ultrasound could effectively break the cell wall of coffee powder and improve its oil extraction efficiency.The results of physicochemical properties and active ingredients of coffee by different extraction methods showed that EE and UE had the lowest acid value and peroxide value,and the highest tocopherol content;while UME active ingredients such as total phenol,kahweol,cafestol,and tocopherol content were higher than the other four methods,followed by ME method.Therefore,combining color,acid value,peroxide value,and tocopherol content,in conclusion,the oil of the UME group was better.Quantitative lipidomics-based coffee oil analysis evaluated three classes of glycerolipids,glycerophospholipids,and sphingolipids including 309 monomeric lipids under four different extraction methods,showing different grouping patterns.We found that TG content in EE and UE extracted coffee oils was the most abundant after quantitative analysis,followed by FFA,while FFA content in ME and UME was the most abundant after quantitative analysis,followed by TG.This may stem from the higher lipid concentration from enzymatic treatment,including 309 monomeric lipids of three glycerolipids,glycerophospholipids,and sphingolipids,showing different grouping patterns.Lipid molecular species and concentrations were significantly altered across treatments in coffee oils extracted using different extraction methods,and metabolic pathway analysis of the identified differential lipids revealed significant enrichment of lipids in the glycerophospholipid and sphingolipid metabolism pathways.The findings of the multifactorial statistical analysis demonstrate that coffee oils treated towithiverse processing methods are significantly different,and the significantly different lipids identified can be employed as possible biomarkers.