本文研究β-环糊精(β-cyclodextrin,BC)对植物乳杆菌发酵大麦粉提取物(fermented barley extract of Lactobacillus plantarum,LFBE)的抗氧化及结构稳定性的增强作用,以期制备具有预期生物活性的较稳定LFBE。采用冷冻干燥法制备BC与LFB...本文研究β-环糊精(β-cyclodextrin,BC)对植物乳杆菌发酵大麦粉提取物(fermented barley extract of Lactobacillus plantarum,LFBE)的抗氧化及结构稳定性的增强作用,以期制备具有预期生物活性的较稳定LFBE。采用冷冻干燥法制备BC与LFBE包埋物(fermented barley extract of Lactobacillus plantarum embedding with BC,BLFBE)冻干粉,借助扫描电镜和X-射线衍射技术研究其微观结构。抗氧化活性实验结果表明,LFBE在常温贮藏12 h后,其多酚化合物含量由(0.30±0.11)mg/m L迅速降至(0.019±0.0023)mg/m L,其DPPH自由基清除率由67.95%±2.16%降至9.16%±0.65%,·OH自由基清除率由72.97%±3.01%下降至11.14%±3.16%;采用1.6%的BC对LFBE进行包埋处理后,BLFBE内多酚化合物含量由(0.25±0.015)mg/m L仅降至(0.21±0.01)mg/m L,其DPPH自由基清除率由52%±2.01%则仅降至45%±2.43%,·OH自由基清除率由67.16%±1.31%仅降至54.74%±2.53%。LFBE色度检测结果表明,BC包埋作用能显著抑制LFBE的L*值在常温24 h内的快速下降,使其在冷冻干燥前保持稳定色泽。扫描电镜图显示,LFBE冻干粉为不规则片状结构,而经BC包埋后变为易分散的类球状结构;X-射线衍射结果发现LFBE冻干粉为非晶型、不定型结构,经BC包埋的BLFBE冻干粉出现晶体结构。因此,采用BC直接包埋LFBE,可有效抑制LFBE抗氧化活性下降与褐变,并增加BLFBE冻干粉的结构稳定性。展开更多
Based on the molecular polarizability effect index,a formula of three parameters was proposed to calculate the boiling point of aliphatic aldehydes and alkanones.ln（820.5-Tb）=6.38330-1.37357×10-1Nc+5.39350ΔE...Based on the molecular polarizability effect index,a formula of three parameters was proposed to calculate the boiling point of aliphatic aldehydes and alkanones.ln（820.5-Tb）=6.38330-1.37357×10-1Nc+5.39350ΔEPI+8.02603×10-2NWhere the Nc is the effective length of carbon chain of alkyl group in the aliphatic aldehydes and alkanones.The ΔPEI is the polarizability effect index difference between the corresponding branched and normal alkyl isomer containing the same carbon atom number,which expressed the effcet of carbonyl group on the boiling point of ali-phatic aldehydes and alkanones.N is the carbon numbers of aliphatic aldehydes and alkanones.展开更多
文摘本文研究β-环糊精(β-cyclodextrin,BC)对植物乳杆菌发酵大麦粉提取物(fermented barley extract of Lactobacillus plantarum,LFBE)的抗氧化及结构稳定性的增强作用,以期制备具有预期生物活性的较稳定LFBE。采用冷冻干燥法制备BC与LFBE包埋物(fermented barley extract of Lactobacillus plantarum embedding with BC,BLFBE)冻干粉,借助扫描电镜和X-射线衍射技术研究其微观结构。抗氧化活性实验结果表明,LFBE在常温贮藏12 h后,其多酚化合物含量由(0.30±0.11)mg/m L迅速降至(0.019±0.0023)mg/m L,其DPPH自由基清除率由67.95%±2.16%降至9.16%±0.65%,·OH自由基清除率由72.97%±3.01%下降至11.14%±3.16%;采用1.6%的BC对LFBE进行包埋处理后,BLFBE内多酚化合物含量由(0.25±0.015)mg/m L仅降至(0.21±0.01)mg/m L,其DPPH自由基清除率由52%±2.01%则仅降至45%±2.43%,·OH自由基清除率由67.16%±1.31%仅降至54.74%±2.53%。LFBE色度检测结果表明,BC包埋作用能显著抑制LFBE的L*值在常温24 h内的快速下降,使其在冷冻干燥前保持稳定色泽。扫描电镜图显示,LFBE冻干粉为不规则片状结构,而经BC包埋后变为易分散的类球状结构;X-射线衍射结果发现LFBE冻干粉为非晶型、不定型结构,经BC包埋的BLFBE冻干粉出现晶体结构。因此,采用BC直接包埋LFBE,可有效抑制LFBE抗氧化活性下降与褐变,并增加BLFBE冻干粉的结构稳定性。
基金Program for New Century Excellent Talents in University ( Grant No NCET-08-0774)the National S & T Major Project of China ( Grant No 2009ZX09501-001)the 111 Project ( Grant No B07023)
文摘Based on the molecular polarizability effect index,a formula of three parameters was proposed to calculate the boiling point of aliphatic aldehydes and alkanones.ln（820.5-Tb）=6.38330-1.37357×10-1Nc+5.39350ΔEPI+8.02603×10-2NWhere the Nc is the effective length of carbon chain of alkyl group in the aliphatic aldehydes and alkanones.The ΔPEI is the polarizability effect index difference between the corresponding branched and normal alkyl isomer containing the same carbon atom number,which expressed the effcet of carbonyl group on the boiling point of ali-phatic aldehydes and alkanones.N is the carbon numbers of aliphatic aldehydes and alkanones.
