银杏叶提取液结合异抗坏血酸钠对鲜切砀山梨贮藏品质的影响

目的:研究银杏叶提取液结合异抗坏血酸钠对鲜切梨的保鲜效果。方法:以鲜切砀山梨为材料,探究总黄酮含量分别为0.25(处理1)、0.50(处理2)、0.75 mg/m L(处理3)的银杏叶提取液结合1%的异抗坏血酸钠(D-sodium ascorbate,D-VCNa)溶液对鲜切砀山梨在4℃条件下贮藏品质的影响。采用SPSS软件分析了贮藏期间鲜切梨的呼吸强度、质量损失率、色差、VC含量、硬度、可溶性固形物含量(soluble solid content,SSC)、过氧化物酶(peroxidase,POD)活力、相对电导率及pH值的变化等。结果:不同质量浓度黄酮的银杏叶提取液结合D-VCNa溶液都可以在不同程度上减缓鲜切梨的呼吸强度、质量损失率、色差的增加,减缓VC含量、硬度、SSC的下降速率,延迟褐变发生、POD活力高峰的出现时间,抑制果实pH值和相对电导率的上升。结论:银杏叶提取液结合D-VCNa对鲜切砀山梨的贮藏品质有一定的保鲜作用,其中以总黄酮含量为0.50 mg/m L银杏叶提取液结合1%的D-VCNa溶液处理的鲜切梨保鲜效果最好。     

银杏叶黄色素提取及稳定性研究

为充分利用银杏资源,增加其经济附加值及为寻找新的天然食品着色剂提供依据,从提取剂选择、液料比、提取温度、时间等条件对银杏叶黄色素的提取工艺及色素的耐光、热、pH 的稳定性进行研究。结果表明,该色素的石油醚溶液在可见区445nm 处有最大吸收;适宜的提取工艺条件为：以乙酸乙酯对石油醚的体积分数为70% 的混合溶剂、液料比25:1(mL/g)、提取温度40℃、提取时间30min,以此方法提取4 次较为彻底;经初步纯化的得率为3.0%,色价20.49。稳定性研究结果表明,银杏叶黄色素对光不稳定,宜避光保存;该色素在60℃以下加热1h 降解率较小,但在70℃加热1h 降解率较大;该色素在弱酸和弱碱条件下较稳定。     

银杏葡萄酒陈酿过程中香气成分的变化

采用溶剂萃取法萃取香气成分,气质联用仪进行检测,结合计算机检索技术对分离化合物进行鉴定,在葡萄酒发酵过程中添加银杏叶提取物与未添加的葡萄酒香气成分及香气成分在陈酿过程中变化进行对比研究。共分离出32 个峰,鉴定出29 种成分,其中主要包括醛类、醇类、酯类和呋喃类芳香成分。对照葡萄酒和银杏葡萄酒在开始陈酿和陈酿1 年后对比分析结果表明：银杏提取物的添加对葡萄酒的香气成分有一定影响,但经过1 年陈酿后,银杏葡萄酒与对照葡萄酒香气成分差异缩小,主要香气物质在种类和含量上都比较接近。     

提取分析银杏叶中黄酮类化合物的研究进展

概述了目前银杏叶中黄酮类化合物的提取工艺和分析方法。提取工艺有：水蒸气蒸馏法、有机溶剂萃取法和超临界流体萃取法。分析方法有：分光光度法、气相色谱法、ＨＰＬＣ法和超临界流体色谱法。根据分离与提纯技术的新进展提出了发展方向。     

银杏叶加工现状和前景

综述了我国银杏叶提取物加工之现状,提出了保证产品质量,降低生产成本的根本办法在于选择优质原料和采用先进生产工艺。作者通过实验证明,选用黄酮苷含量≥１．２０％,萜内酯含量≥０．３０％的优质银杏叶作原料,采用先进工艺,每ｋｇ银杏叶提取物的生产成本可降至１０００元以下。     

鲜白果和熟制白果挥发性成分的分析

采用固相微萃取和气质联用(SPME-GC-MS)技术对鲜白果、微波熟制白果和煮制熟制白果挥发性化合物进行测定,并利用主成分分析法(PCA)对三者的挥发性化合物进行比较分析。结果表明:熟制白果与鲜白果挥发性化合物存在较大差异,从中共检出66种挥发性化合物。鲜白果中检出44种,主要挥发性成分为醛类;微波熟制白果中检测出35种挥发性成分,醇类相对含量较高;煮制熟制白果中有31种挥发性成分被检测出,萜类含量和种类最高。PCA分析发现新鲜白果的挥发性成主要指向醛类,微波和煮制熟制白果的挥发性成分主要指向萜类。     

银杏叶提取物中组分定性检测及含量测定

通过显色反应实验、泡沫实验和pH试纸对银杏叶提取物中组成成分类别进行定性测试,并采用UV法和高效液相色谱(HPLC)法测定银杏叶提取物中成分含量。银杏叶提取物均含有黄酮、有机酸、多糖、蒽醌、鞣质、萜类化合物,无皂苷和生物碱类化合物(去掉了各成分含量范围)。两种银杏叶提取物中黄酮、有机酸、多糖、蒽醌、萜类化合物含量相差不大,鞣质在2015年版药典银杏叶提取物中含量明显高于水溶性银杏叶提取物。为银杏叶提取物质量整体评价及安全、稳定性研究提供数据参考。     

银杏种仁中活性成分及其药理作用的研究进展

本文综述了银杏种仁中化学活性成分,及其药理作用,并对银杏种仁的综合利用和存在问题进行了讨论.     

Changes in Polar Metabolites Content during Natural and Methyl-Jasmonate-Promoted Senescence of Ginkgo biloba Leaves

The present study clarified changes in the contents of polar metabolites (amino acids, organic acids, saccharides, cyclitols, and phosphoric acid) in leaf senescence in Ginkgo biloba with or without the application of methyl jasmonate (JA-Me) in comparison with those in naturally senescent leaf blades and petioles. The contents of most amino acids and citric and malic acids were significantly higher in abaxially, and that of myo-inositol was lower in abaxially JA-Me-treated leaves than in adaxially JA-Me-treated and naturally senescent leaves. The levels of succinic and fumaric acids in leaves treated adaxially substantially high, but not in naturally senescent leaves. In contrast, sucrose, glucose, and fructose contents were much lower in leaf blades and petioles treated abaxially with JA-Me than those treated adaxially. The levels of these saccharides were also lower compared with those in naturally senescent leaves. Shikimic acid and quinic acid were present at high levels in leaf blades and petioles of G. biloba. In leaves naturally senescent, their levels were higher compared to green leaves. The shikimic acid content was also higher in the organs of naturally yellow leaves than in those treated with JA-Me. These results strongly suggest that JA-Me applied abaxially significantly enhanced processes of primary metabolism during senescence of G. biloba compared with those applied adaxially. The changes in polar metabolites in relation to natural senescence were also discussed.     

Immunohistological evidences of Ginkgo biloba extract altering Bax to Bcl-2 expression ratio in the hippocampus and motor cortex of senescence accelerated mice

Ginkgo biloba extract 761 appears to display neuroprotective effect in many nervous diseases and aging. Deterioration of mental functions during aging is always accompanied by loss of neurons, presumably through apoptosis. Here, we studied the effect of G. biloba extract in the expression of Bax/Bcl-2 ratio, an important apoptotic index, in the hippocampus and motor cortex of the aging brain. Bax and Bcl-2 expressions were examined with immunohistochemical methods. Senescence Accelerated Mice Prone Strain 8 was used because the aging process was accelerated with neuropathological alterations similar to those found in the aging human brain. The mice were fed with either G. biloba extract or sucrose from the age of 3 weeks until sacrifice at 3 or 9 months old. In the hippocampus of G. biloba fed 9-month-old mice, the ratio of Bax positive cell to Bcl-2 positive cell (Bax/Bcl-2 expression ratio) was 11.43 +/- 3.11 (mean +/- SD); significantly lower (P < 0.05) than the Bax/Bcl-2 expression ratio of 20.99 +/- 5.34 in the sucrose fed mice. The Bax/Bcl-2 expression cell ratios, however, in the motor cortex were not significantly different between the two groups (2.22 +/- 1.35 versus 2.27 +/- 2.02 for the G. biloba and the sucrose fed mice, respectively). The decrease in the Bax/Bcl-2 expression cell ratio following G. biloba treatment might hence be able to protect the aging hippocampus from moving further down the apoptotic pathway. Western blotting confirmed the decrease of Bax in the brain even after a short term and high dose Ginkgo treatment. It is speculated that the G. biloba extract may be a potential neuroprotective agent against apoptosis through the differential expressions of the Bax and Bcl-2 in the hippocampus.