| Cane brown sugar is a noncentrifugal brown sugar prepared from sugarcane juice with the processes of pressing,extracting,clarifying,boiling,and concentrating.As well known,cane brown sugar contains various nutritional components like animo acids and has various biological functions with beneficial effects on human health,including antioxidant effects and antiatherosclerotic activities.It is popular because of the promotion of human metabolism and prevention of diseases.The quality of cane brown sugar is getting more attention and the aroma profile is an important indicator which can influence both flavor and organoleptic quality directly.In this study,a method was found that united extraction technology and analysis means to detect the volatile components and the possible precursors were also investigated.The main research contents are as follows:1.Gas Chromatography-Mass Spectrometry(GC-MS)was used for the comparison of Simultaneous distillation extraction(SDE)and Solid-phase micro extraction(SPME)for analysis of the aroma volatile components of cane brown sugar.The amount and total peak area were considered as the indicator.37 volatile components with the total area of 336407261 and 47 volatile components whose total area detected as 402380424 were identified respectively by the united technology of SDE-GC-MS and SPME-GC-MS.As shown,more volatile components especially pyrazines and aldehyde ketones which usually give nutty,fruity/grassy aroma could be identified by SPME-GC-MS.Thus,SPME method provided better result in extraction when the total peak area and flavor compounds were both examined and was proved more suitable for the extraction of volatile components in cane brown sugar.2.Optimization experiments were operated on sample content,sample dosage,NaCl dosage,extraction temperature and extraction time,and as a result,NaCl dosage,extraction temperature and extraction time were proved to have a great influence on the extraction efficiency of SPME.Then a orthogonal test was designed on these three essencial factors and the optional condition for cane brown sugar extraction:6g samples at 60%concentration was needed as well as 0.6g NaCl,and the SPME extraction was carried out under 50? for 50min.62 volatile aroma compounds were found in cane brown sugar by SPME combined with GC-MS analysis,including aldehydes,pyrazines,ketonesand phenols.3.The volatile aroma compounds of five kinds of cane brown sugar and one refined sugar were identified by SPME-GC-MS/GC-O and elect-ronic nose which combined with PCA was uesd to reflect the similarities and differences of different samples.As results,131 volatile components were detected in which dimethyl sulfide,2-methyl furan,2-methyl butan-al,toluene,hexanal,2,6-dimethyl pyrazine,methylheptenone,2-ethyl-6-methyl-pyrazine,2-ethyl-5-methyl-pyrazine,furfural,2,3,5-trimethyl-pyr-azine,benzaldehyde,5-methyl-2-Furanme-3-thanol,damassolone,2-ace-tylpyrrole,2,4-ditert-butylphenol and 2-meth-oxy-4-vinylphenol were found in all of the samples.Methylpyrazine,octanal,furfural and butyric acid were considered as the most contributed odor-active compositions to the overall aroma characteristic of cane brown sugar for their high level of OAV(>1000),aroma intensity(? 2)and FD(? 729)by using GC-O analysis with the application of AEDA.4.The changes of aroma compounds during the making process of cane brown sugar were studied in this paper and 90 volatile compositions were identified,moreover,50 components were detected both in sugarcane juice and sugar syrup respectively while 62 were found in cane brown sugar.Maillard reaction between sugar composition and amino acids is really important for the formation of aroma in cane brown sugar during the making process.In this study,original content of Glu,Gly,Val,Ile,Leu,Lys and His was>1mg/g,and all of them decreased over 50%.Thence,these amino acids were considered as essential precursors for the formation of aroma in cane brown sugar as well as fructose and glucose. |
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