| Areca catechu L.are evergreen trees from Areca of Palmaceae,which are native to Malaysia,mainly distributed in tropical regions of Asia and the America.According to the different parts of the food and edible methods,Areca catechu L.are divided into the edible betel nut and arecae semen.Arecae semen is dry and mature seed from the Areca plant Areca catechu L.,which are mostly used for decoction.At present,there are three kinds of processed products commonly used.They are raw,fried and coked products.The edible betel nut is immature fruit,chewed with the exocarp.Based on the edible habits from global people fond of chewing it,the edible betel nuts are divided into fresh betel nut and dry betel nut.The former is mostly cutting the seven to eight mature fresh betel nut fruit into several petals,chewing with the piper leaves wrapped in gray.The latter is the fresh betel nut soaked with lime water,processed with strong alkaline,irritating strong fragrance,spices and other special treatment for the dry betel nut.Objective:1.Comparative study of the chemical composition in different processed products of arecae semen and the edible betel nut by means of using LTQ-Orbitrap MS.To clarify the difference between the chemical composition of arecae semen and the edible betel nuts and illustrate the compotent change in different processing products,based on the difference of the contents of unsaturated fatty acids,four main alkaloids and tannins.2.Identification of different kinds of areca nut using LTQ-Orbitrap MS with a multivariate statistical sample profiling strategy,to illustrating the chemistry component change in different areca nut samples.3.To determine the content of arecoline,guvacoline,arecaidine and guvacine in arecae nut,a simple and rapid HPLC method has been developed.Determinate the alkaloids composition of arecae semen and the edible betel nut.4.To determine the content of linoleic acid and oleic acid in arecae nut,a simple and rapid HPLC method has been developed.Determinate the unsaturated fatty acids composition of arecae semen and the edible betel nut.5.Determination of the content of tannins in samples of arecae semen and the edible betel nut.Combined with multivariate statistical analysis,to clarify the effect of the processing method on the chemical composition of areca semen and the edible betel nut,and find the difference of the main composition between arecae semen and the edible betel nut.Methods:1.Comparative study of the chemical composition in different processed products of arecae semen and the edible betel nut by means of using LTQ-Orbitrap MS.To clarify the difference between the chemical composition of arecae semen and the edible betel nuts and illustrate the compotent change in different processing products,based on the difference of the contents of unsaturated fatty acids,four main alkaloids and tannins.The LC separation was performed on an Ultimate 3000 HPLC system with an Ultimate XB-SCX column(4.6×250 mm,5 μm).The column temperature was set at 25℃.The flow rate was kept at 1 ml/min.Mobile phase A was water with 0.1%formic acid,and mobile.phase B was acetonitrile.The total run time was 55 min,and the injection volume was 4μL.The ionization mode were positive electrospray(ESI+)and negative electrospray(ESI-).The desolvation temperature was set at 350℃ with Sheath air flow rate set at 30L/h.The capillary voltage were set at 4.0/3.0 kV.The cone voltage were set at 25/-35V.2.High performance liquid chromatographic method was used for determining the common alkaloids,arecoline,guvacoline,arecaidine,guvacine of betel nut samples.Chromatographic condition:Ultimate XB-SCX(4.6×250mm,5μm),mobile phase:acetonitrile(A)and 0.2%phosphate solution(B)(72:28),the flow rate:1 ml/min,the total run time was 30 min,and the injection volume was 20μL,detector wavelength:215nm,column temperature:25℃.3.High performance liquid chromatographic method was used for determining the linoleic acid and oleic acid of betel nut samples.Chromatographic condition:Agilent Zobrax SB-C18,(4.6×250 mm,5 μm),mobile phase:acetonitrile(A)and 0.1%phosphate solution(B)(88:12),the flow rate:1 ml/min,the total run time was 30 min,and the injection volume was 20μL,detector wavelength:205nm,column temperature:30℃.4.Determination of tannins in arecae semen and the edible betel nut by using phosphomolybdium tungstic acid-casein ultraviolet-visible spectrophotometry.5.The variance analysis and multiple comparisons of the above experimental results of arecae semen and the edible betel nut were carried out by SPSS 20.0 software.The principal component analysis and partial least squares-discriminant analysis were performed by using SIMCA-P+12 software.Results:1.The chemical composition of arecae semen and the edible betel nut were compared with the LC-MS technology.The difference of chemical composition between different specifications of betel nut was clarified under the molecular level.The fried and coked betel nuts did not detect the dodecenoic acid which is detected in the raw betel nut.But they had jacareubin and methyl nicotinate,which the raw betel nut did not exist.There are more differences of the compounds between the edible betel nut and arecae semen:Ethyl-N-methyl1,2,5,6-tetrahydro-pyrimidine-3-carboxylate,proline,succinic acid,jacareubin.2.Based on the combination of liquid mass spectrometry and multivariate statistical analysis,the differences from chemical composition of different kinds of areca nut samples were studied.The characteristic compounds in the edible betel nut are ethyl maltol and ethyl acetate,which,are the edible essence.And the arecae semen have the procyanidins and cleistanthin A.3.Results shows that the HPLC has been established the 4 common alkaloids(arecoline,guvacoline,arecaidine,guvacine),2 unsaturated fatty acids(Linoleic acid,oleic acid)for quantitative analysis.The precision and repeatability of the method were less than 2%,and the average recovery rate and RSD value were all in line with the requirements.The results shows that the sum of 4 alkaloids in the raw,fried and coked arecae semen and the edible betel nutwere 1.01%,0.82%,0.71%and 0.47%,respectively.And the linoleic acid contents were 0.55%,0.16%,0.08%,0.87%;the oleic acid contents were 0.90%,0.30%,0.12%,0.48%.4.The content of total tannins in arecae semen and the edible betel nut were determined by phosphomolybdium tungstic acid-casein UV-Vis spectrophotometry.The linearity of the concentration was good within a certain range.The results shows that the total tannins content of the raw,fried and coked arecae semen and the edible betel nut were 10.33%,10.98%,8.61%and 3.61%,respectively.5.The principal component analysis and partial least squares-discriminant analysis were used to find the difference between the different specifications of betel nut samples.The value of VIP was obtained by PLS-DA analysis.The order was that arecoline(1.2012)>guvacoline(1.1405)>linoleic acid(1.0304)>tannins(1.0149)>arecaidine(0.9958)>oleic acid(0.9273)>guvacine(0.5595).Conclusions:1.Comparative study of the chemical composition in different processed products of arecae semen and the edible betel nut by means of using LTQ-Orbitrap MS.To clarify the difference between the chemical composition of arecae semen and the edible betel nuts and illustrate the compotent change in different processing products.Finding that the difference between the chemical compositions of different specifications of arecae semen is not significant,there are only a few characteristic compounds:jacareubin.There are more differences of the compounds between the edible betel nut and arecae semen.The characteristic compounds in the edible betel nut are phospholipid components.And the arecae semen have the procyanidins B and cleistanthin A.2.High performance liquid chromatography can be used to establish a stable and reliable method for the determination of the chemical compositions contained in different samples of betel nut.In the view of alkaloids,the contents of 4 main alkaloids in the raw,fried,coked betel nut and the edible betel nut samples are different.During the processing procedure,arecoline and guvacoline volatile due to the heat.Besides,under the alkaline environment,they can hydrolyze into arecaidine and guvacine during the brine seasoning process of dry betel nut produced.3.The phosphomolybdium tungstic acid-casein UV-Vis spectrophotometry is accurate,sensitive and reliable.It can be used to determine the content of tannins in betel nut samples.The overall trend of tannins contents:fried betel nut>raw betel nut>coked betel nut>the edible betel nut.Indicating that the processing technology can influence the content of tannins in betel nut,the heating temperature and time are the key impacted factors.The contents of tannins increases while the heating temperature and time are moderate.4.Finding out the differences between the different specifications of betel nut samples by using principal component analysis and partial least squares-discriminant analysis,and the contents of arecoline and guvacoline can be used to distinguish between arecae semen and the edible betel nut. |
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