Study On Fingerprint Of Phenolic Compounds And Fatty Acids In Pulp Of Litchi

Focusing on the making process of litchi and qualitative and quantitative control of the Litchi juice. The following research have been conducted:(1) Analysis of phenolic compounds in pulp of litchi by high performance liquid. (2) Study on HPLC Fingerprint of polyphenol in pulp of litchi. (3) Analysis of fatty acid in pulp of litchi by GC-MS. (4) Study on GC-MS Fingerprint of fatty acids in pulp of litchi. The main conclusions of this paper are as follows.1. Analysis of phenolic compounds in pulp of litchi by high performance liquid chromatography-tandem mass spectrometryHigh performance liquid chromatography(HPLC)-DAD detection-electrospray ionization(ESI) mass spectrometry was used to determine the phenolic compounds in pulp of litchi. Mass spectrometry in tandem mode with negative iondetectio, full scan, multireaction monitor and neutral loss model were used. Phenolic compounds were separated in 45min, the main phenolic compounds were characterized according to HPLC retention times, MS data, spectral data, and literature references. This study firstly characterized 11 phenols including procyanidin B2, procyanidin trimer, procyanidin dimmer, quercetin-3-rutinoside, isorhamnetin-3-rutinosideown, didymin, (-)-epicatechin from the pulp of litchi.2. Study on HPLC Fingerprint of polyphenol in pulp of litchiUnder the chromatographic conditions:SB-C18 column, UV detector, acetonitrile (A) and 0.4% glacial acetic acid (B) as mobile phase, column temperature 35℃, injection volume 20μl, flow rate 1mL/min, detection wavelength 280nm, linear gradient wash off: 0～40min A 5%～25%,40～45min A 25%～35%,45～50min A 35%～50%,17 different varieties of litchi pulp polyphenol was studied and the litchi polyphenols HPLC fingerprint was established, obtaining 13 common peaks. Data was analyzed by fingerprint similarity evaluation software and SPSS software, the two methods showed the same conclusion. In this study, the retention time in 25.35min was identified as rutin-rhamnose,which was the characteristics polyphenols composition.Through comparison of the relative peak area of peaks of the preliminary determination, we can identify the different breed of litchi, by comparing the overview map, we can control the quality of Litchi Juice. 3. Analysis of fatty acid in pulp of litchi by GC-MSThe pulp of litchi was extracted by mixture of chloroform and methanol. The fatty acids were esterified by hydroxide-methanol, and then established by capillary gas chromatography.16 fatty acids were identified in the pulp of litchi and were rich in unsaturated fatty acids.9-Octadecenoic acid is the major fatty acid (44.41% of total fatty acids) followed by Hexadecanoic acid (25.14%) and 9,12-Octadecadienoic acid (18.91%). The saturation fatty acid (SFA) were:pentadecanoic acid, Hexadecanoic acid, Heptadecanoic acid, Octadecanoic acid, Eicosanoic acid, Docosanoic acid (28.44%), monounsaturated fatty acid (MUFA) were:7-Hexadecenoic acid, cis-9-Octadecenoic acid, trans-9-Hexadecenoic acid, oleic acid, trans-9-octadecenoic acid,10-octadecenoic acid, 11-Eicosenoic acid (52.46%) and polyunsaturated fatty acid (PUFA) were:linoleic acid, 11,14-Eicosadienoic acid, (19.11%).4. Study on GC-MS fingerprint of fatty acids in pulp of litchiUnder the gas chromatography conditions:HP-5 fused silica capillary column (30 m×0.25 mm×0.25μm); temperature program was initial temperature 180℃; keep 1min; 2℃per minute rose to 215℃; keep 5 min. Injector temperature 230℃; detector temperature was 250℃; Injection volume 3μL; solvent delay 5 min; carrier gas (He) flow 60 mL·min-1; not divert. Study on fatty acids of 17 samples, the fatty acid fingerprints was established, the data was analysised by SPSS software,17 samples can be divided into three basic categories.4 peaks were obtained by using the chloroform: methanol (2:1) to extract, then take 10 mL methyl chloroform layer, esterified by hydroxide-methanol.16 peaks were obtained by using the chloroform:methanol (1:1) to extract, then collect all of the methyl chloroform layer, esterified by hydroxide-methanol, finally concentrated by the nitrogen. Comparing with the two different pretreatment methods, the 16 peaks contained more information than 4 peaks. For the principle of characteristic, the pretreatment which obtained 16 peaks was more useful for the quality control of litchi juice. But the pretreatment which obtained 4 peaks is simple. People can avoid the operation of experimental individuals which caused the error, this method is more suitable for early detection. Use which method can depend on the actual situation.