| Caramel is widely used in food industryas a colorants,which mainly used for soy sauce,vinegar and other food coloring.In China,large amount of soy sauces are produced and sold,to promote the technical progress of caramel pigment.Ammonia caramel for its high color indensityis used by most enterprises,and its drawback is that in the preparation process will produce 4-MI(4-methylimidazole).4-MI is a potentially carcinogenic substance with side effects,its security by the vast number of consumers questioned.Therefore,it is a major breakthrough to prepare non-4-methylimidazole,high-quality caramel in the food field.In this thesis,the optimized conditions for the preparation of high color index and non-4-methylimidazole are determined by single factor and orthogonal array design,using sucrose as raw material.Based on these,the physical and chemical properties of plain caramel are discussed,and the components of the distillate were identified.The plain caramelis classified by ultrafiltration technique,organic composition,molecular weight and antioxidant activity were compared and analyzed.Details as follows:Single factor and orthogonal array design,and comprehensive equilibrium analysis methodsare used to optimize the technological parameter during plain caramel.The best productprepared under the conditions of using sucrose at 200 ℃ for 3 h,and collecting distillate 8 mL,with 50 mL 3% sodium carbonate solution as reactant,is obtained with the color intensity 14508 EBC,red index 6.51,yellow index 9.69 and overcomed the shortcomings of plain caramel poor salt tolerance.The physicochemical properties,safety,practical application and the volatile components of the plain caramel are studied and evaluated.It was found that the plain caramel had the characteristics of high red and yellow index,good salt tolerance,moderate p H,long resinization time,non-4-methylimidazole,ruddy color and strong saturation.The distillation is detected by Gas Chromato-graphy-Mass Spectrometry(GC-MS)and 22 kinds of natural flavor component or their precursors are identified,and furan and ketone compounds account for more than 90% of the volatile components.These volatile substances are mostly natural flavor substances and their precursors,the study for the development of caramel flavor provides technical support.The physical and chemical properties,organic composition,molecular weight and antioxidant activity of ultrafiltration were studied.The results showed that the color intensity of plain caramel increased with the increase of molecular weight,and the red/yellow index decreased with the increased of molecular weight.The results of infrared spectraand UV full band scanning showed that the waveforms of plain caramel and all of which have antioxidant properties.The qualitative and quantitative analysis of plain caramel and graded samples by gas chromatography-mass spectrometry showed that the main components are hydrocarbons,alcohols,esters,aldehydes and ketones.This study provides a theoretical basis for the preparation of safe caramel pigments. |
