| Sorghum is widely planted in China, and it has a long history of being used for liquor-making material. So far, there has been a great amount of research about the effects of its ingredients, including starch, protein and fat on liquor quality. However, relatively little research explores the effect and its mechanism of SPC featuring the activity of suppressing bacteria and mediating enzyme on the volatile ingredients of distilled liquor. The research on procyanidins has lasted over 40 years, but there are only a few literatures about SPC in sorghum. Based on analyzing and identifying the SPC content of sorghum from different region of China, the research was conducted (1) to study the effect of SPC in sorghum on the volatile ingredients of distilled liquor, (2)to probe its mechanism by analyzing the effect of SPC in sorghum on the classical microbes and enzymes in distilled liquor, (3) to provide scientific evidence for delving into the effect of SPC in sorghum on white spirit-making and improving its flavor, and (4) to offer supporting resources for deep processing and application of outer husk of sorghum. The main results are as follows: 1. Methods for extraction, purification and determination of content of SPCThe analytical result of SPC in sorghum collected from 11 main planting region, such as Hubei, Anhui, Heilongjiang showed that (i) SPC was mainly distributed in the episperm of sorghum, reaching 96% of total procyanidins, (ii) SPC content differed (1.24%~8.42%) in the episperm of sorghum from different locations, in which the maximum SPC content was 8.42% from Anhui. This indicated that SPC content in sorghum varied from region to region.The extraction rations of procyanidins from soghum (SPC) was compared using different solvents, such as water, different volume rates of acetone to water, methanol to water and ethanol to water. Through single factor and orthorhombic analysis, ethanol/water (50:50v/v) was selected as extracting solvent and the best extracting process. At the same time, the control conditions were obtained, including temperature (80), pH (4), the ratio of material to extracting solvent (1:20W/V), extracting time (90min).Then SPC was purified by chromatography with macro-porous resin as stationary phase. Water was used to elute foreign matter, and then 30% ethanol was used to elute SPC,whose content was 96.01% and the yield was 3.76%.2.Separation, identification and chemical structure characteristics of procyanidins insorghum from Heilongjiang2.1 Structural Analysis of SPCStructure of SPC was analyzed with UV> IR and MS. SPC showed UV and IR spectrogram of procyanidins. ESI-MS spectrogram indicated that SPC consisted of monomer, dimmer, trimer, tetramer, pentamer of procyanidins, epicatechin gallate ester and epicatechin. Their molecular weights are 290, 578, 866, 1154, 1442, 466 and 306 respectively.2.2 Separation of SPC and chemical structure characteristics of SPC-4SSPC were separated with gradient of step elution model in Sephadex LH-20 gel chromatogram. Porter's method and ESI-MS was used to determine the content and constitute of procyanidins in each fraction. Different ethanol to water ratio mobile phase was used with gradient of step elution followed by 70% acetone/ water isocratic elution, and gained 6 fractions (SPC-1S-5S and 6S respective). The content and degree of polymerization of procyanidins in each fractions increased with the rising of ethanol concentration. The SPC-2S fraction with 30% EtOH were constituted epicatechin and epicatechin gallate ester ; The SPC-2S fraction with 50% EtOH contained epicatechin and dimeric procyanidins, another SPC-3S contained epicatechin ,dimeric procyanidins and trimeric procyanidns ; Dimeric procyanidins and trimeric procyanidns constitute SPC-5S fraction; monomer dimer trimer tetramer pentamer of procyanidins were the major fractions in 70% acetone elute solution.ESI-MS NMR and IR was used in determining SPC-4S fraction of gradient of step elution model, the results showed the dimeric , trimeric, tetrameric procyan...
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