Improvement of quality of Ginkgo biloba seeds powder by solid-state fermentation with Eurotium cristatum for developing high-value ginkgo seeds products

In this study,we investigated the feasibility of Ginkgo biloba seeds powder by solid-state fermen-tation with Eurotium cristatum for developing high-value ginkgo seeds products.The optimum fermentation medium was consisted of 10 g of 40-mesh ginkgo seeds powder loaded in 100 mL Erlenmeyer flask with 50%(w/w)of water content,4%(w/w)of MgSO_(4)and 5%(w/w)of KH_(2)PO_(4)addition.The optimum fermentation conditions were pH 5.0,2×10^(8)CFU/g of inoculum size,3 mL of sterilized water supplemented every two days during the four days of fermentation.Through fermentation,the spore number of E.cristatum was improved by about 36 times with the produc-tion of lovastatin reaching(54.10±0.16)μg/g.The antioxidant activity of fermented ginkgo seeds powder also got obvious enhancement,which could help eliminate excess free radicals produced by normal metabolism.The content of free amino acids increased by 82.32%.Except that the sugar was consumed in some degree,the other nutritional and functional components were well preserved while the content of detrimental ginkgolic acids was reduced by 44.97%.In addition,fermented ginkgo seeds powder possessed better digestibility and showed pleasant orange-like smelling.In conclusion,the quality of ginkgo seeds powder was remarkably improved through solid-state fermentation by using E.cristatum,which could be a promising way for functional applications of ginkgo seeds.

Two new phenolic glycosides isolated from Ginkgo seeds

Two new phenolic glycosides, 7S, 8R-urolignoside-9′-O-β-D-glucoside(1) and scrophenoside G(2), were isolated and identified from the seeds of Ginkgo biloba L., a famous traditional medicine and functional food around the world. Their structures were elucidated by spectroscopic methods(1D and 2D NMR, HR-ESI-MS, and CD), and the comparisons of spectroscopic data with the reported values in the literature.

Application of oxygen-sensing technology to measure seed quality of Ginkgo biloba

Germination tests are currently the most widely used method to evaluate seed quality of Ginkgo biloba L., but they are time-consuming and labor intensive. Oxygen-sensing technology, based on the principle of fluorescence quenching to detect oxygen and assess seed quality was used to rapidly evaluate seed quality of two varieties (Shandong Tancheng 202 and Zhejiang Dafoshou) of G. biloba from five mother plants. Fifteen samples of three vigor levels were produced by accelerated aging treatments. This process was applied in duplicate. A portable oxygen-sensing detector was employed to measure oxygen content during seed germination in a closed system at 25 A degrees C each day until day 14. Four oxygen metabolism indices were calculated: oxygen consumption index, oxygen consumption rate, critical oxygen concentration, and theoretical germination time (T (GT)). Additionally, we tested laboratory germination and field emergence. The results of a one-way analysis of variance and correlation analysis showed that T (GT) was the candidate index to evaluate seed quality of G. biloba. Therefore, the T (GT) value was used to validate the reliability of oxygen-sensing evaluation for Zhejiang Dafoshou seeds kept under four storage conditions. The trend in the change in oxygen metabolism agreed completely agreement with that of seed germination under all storage conditions. The oxygen-sensing test reliably and rapidly assessed seed quality of G. biloba. The germination rate of Zhejiang Dafoshou was accurately predicted by T (GT).

Dynamic change of protein polypeptide of Ginkgo biloba seed during germination

The dynamic changes of protein polypeptide in endosperms of Gingkgo biloba seeds during seed germination were studied by SDS-PAGE and two-dimensional gel electrophoresis (2-DE). The results showed that 80 kinds of protein spots in endosperms of Gingkgo biloba were clear observed in the 2-DE spectrum. Protein molecular weights were in the range of 26-52kD, and their isoelectric points were in the range of 5.8-7.8. In the course of seed germination, 13 kinds of proteins were degraded, and 13 kinds of proteins were synthesized; 7 kinds of proteins with different molecular weights and isoelectric points of 35kD/pI6.8, 31kD/pI6.8, 29kD/pI6.8, 33kD/pI6.6, 33kD/pI 6.4, 34kD/ pI7.7 and 31kD/pI7.7 were identified primarily as vegetative storage proteins (VSPs).

银杏种仁分离蛋白水解产物的制备及其抗氧化活性研究

采用碱性蛋白酶、菠萝蛋白酶和米曲霉蛋白酶对银杏种仁分离蛋白(GBSPI)进行水解,并通过体外DPPH自由基、羟基自由基和超氧阴离子自由基清除实验评价GBSPI水解产物的抗氧化活性。研究结果表明:碱性蛋白酶、菠萝蛋白酶和米曲霉蛋白酶水解产物的得率分别为93.60%、60.00%和46.80%,水解度分别为13.76%、6.28%和5.55%。3种酶水解产物对DPPH自由基、羟基自由基和超氧阴离子自由基均具有较好的抑制作用,其中,碱性蛋白酶水解产物具有最强的抗氧化活性,其对DPPH自由基、羟基自由基和超氧阴离子自由基的IC 50值分别为5.29、0.35和7.01 g/L。

白果肽的二肽基肽酶-Ⅳ抑制活性及其抑制机理研究

食源性二肽基肽酶-Ⅳ(dipeptidyl peptidaseⅣ,DPP-Ⅳ)抑制肽可有效调节机体内糖代谢,降低机体血糖水平。为评估白果肽(phenylalanine-alanine-proline-serine-tryptophan,FAPSW和methionine-proline-glycine-proline-proline,MPGPP)的降糖潜能,采用体外试验测定其DPP-Ⅳ抑制活性,并进一步通过分子对接和分子动力学模拟揭示其抑制机理。结果表明,FAPSW和MPGPP具有良好的DPP-Ⅳ抑制活性,且MPGPP的DPP-Ⅳ抑制活性[IC_(50)=(0.158±0.009)g/L]强于FAPSW[IC_(50)=(2.540±0.126)g/L];分子对接结果表明,静电相互作用、氢键、疏水作用和范德华力在FAPSW和MPGPP抑制DPP-Ⅳ活性中起重要作用;分子动力学结果表明,FAPSW和MPGPP结合DPP-Ⅳ能形成稳定的复合物结构,且MPGPP-DPP-Ⅳ复合物的稳定性要强于FAPSW-DPP-Ⅳ。结合自由能结果表明,静电相互作用在FAPSW和MPGPP结合DPP-Ⅳ中起主导作用。研究结果可为FAPSW和MPGPP在功能食品领域的开发和利用提供一定的理论参考。

Female Plant Types of Ginkgo biloba L. in China

Ginkgo biloba is a dioecious and unique species within Ginkgo family and Ginkgo genus, but it shows a big variability. From 1950s, resources of female plants in China were investigated and collected, and the seed anatomical structure and morphological characters at different development stages were observed. According to the shape, length, width and thickness of ovule bracket and seed stone, as well as the characteristics of both sides and top of the stone, the female plants of Ginkgo biloba have been divided into five types, long-stone, Buddha-finger, horse-bell, mume-stone and round-stone. In addition, the important cultivars belonging to different types were also determined. The stone weight, index of stone shape, and contents of dry matter, amylose, amylopectin, starch, rough protein, soluble sugar and hydrocyanic acid in seed kernel of each type were measured, and the qualities of seed stone were appraised, which lays a foundation for the improvement and utilization of female plant resources in Ginkgo biloba.

超声处理结合pH值调控对白果分离蛋白/乳清分离蛋白复合凝胶特性的影响

为研究超声处理结合pH值调控对白果分离蛋白与乳清分离蛋白复合凝胶性能的影响,本实验对复合蛋白溶液的物化性质、蛋白分子行为及所形成热诱导凝胶的质构、持水性及微观结构进行表征。结果表明:超声功率为总功率的25%、45%和65%时对蛋白溶解度均无显著影响,超声结合较低的pH值(pH 4.0)处理能够显著降低蛋白疏水性、提高蛋白表面巯基含量并增大溶胶粒径。十二烷基硫酸钠-聚丙烯酰胺凝胶电泳及傅里叶变换红外光谱分析结果证明超声处理影响了蛋白分子的结构和聚集行为。经热诱导后,在较低pH值条件下复合蛋白形成的凝胶质地性能较差,而在较高的pH值条件下(特别是在pH 5.0时)复合蛋白所形成凝胶的质地性能较好,持水性较高。复合蛋白凝胶的质地性能和持水性均随着超声功率的增加而明显提升,其归因于超声处理强化了白果分离蛋白与乳清分离蛋白中羟基基团的相互作用,促进了蛋白分子的聚集和交联,并改善了复合蛋白凝胶结构的紧密性。综上所述,超声处理结合pH值调控可有效改善复合蛋白凝胶的功能特性。

不同银杏无性系种子、种苗质量评价及定向选育

【目的】对银杏种子和种苗的质量进行评价可以为其良种选育、叶用林及果用林的定向培育提供参考依据。【方法】通过研究‘宇香’(YX)等7个银杏无性系种核特征、种子发芽情况、种苗生长及生理代谢情况,对7个无性系进行综合评价和定向选育。【结果】1)7个无性系可划分为佛指、马玲、梅核3种类型。7个无性系中,‘正安1号’(ZA)、‘久寿’(JS)的白果百粒重都高于其他品系,分别比最低的‘洞庭佛手’(DT)高88.2%和82.6%;‘亚甜’(YT)种仁的可溶性糖含量最高;JS种仁的淀粉、还原糖含量最高;DT种仁的总萜内酯含量最高,比最低的JS高50.0%。2)‘苗圃1号’(MP)、‘泰兴佛指’(TX)、YX的发芽率高于其他无性系,最高达81.0%;MP、DT无性系种子发芽较快,16 d达到发芽高峰。MP、YT、YX的发芽势较高。3)无性系TX、DT、YX幼苗的叶片数较多;YT、MP幼苗叶片中的总黄酮最高,ZA、MP总萜内酯含量都高于其他无性系,YT总黄酮比最低的ZA高43.4%,ZA总萜内酯比最低的YX高34.7%。4)7个无性系种子质量综合评价由高到低的顺序依次为:YT> YX> JS> DT> TX> MP> ZA;发芽能力的综合评价排序为:MP> TX> DT> ZA> YX> YT> JS;种苗品质的综合评价由高到低的排列顺数是:YX> YT> TX>MP> ZA> JS> DT。【结论】无性系‘亚甜’‘宇香’‘久寿’食品利用价值较高,可用于果用林的培育;无性系‘苗圃1号’‘泰兴佛指’2个无性系播种品质较好,有利于快速培育苗木;无性系‘宇香’‘亚甜’‘泰兴佛指’‘苗圃1号’可用于叶用林的培育。‘宇香’与‘亚甜’无性系叶用林和果用林培育都适合。

白果中内源性组分吡哆醇对大鼠的急性和亚慢性毒性评价

考察了白果中内源性组分吡哆醇对SD大鼠的急性和亚慢性毒性。在急性毒性试验中,根据《食品安全国家标准GB15193.3-2014》中的限量法对SD大鼠单次灌胃5000 mg·Kg^(-1)吡哆醇,测试其半致死量(LD 50)。在亚慢性毒性试验中,根据《食品安全国家标准GB15193.22-2014》进行实验,分别以3.15、15.8、31.5 mg·Kg^(-1)的吡哆醇连续灌胃SD大鼠28 d,观察大鼠生理状况及体重变化情况,并对大鼠的脏器指数、血清生化指标、病理组织切片和氧化应激能力进行分析。结果表明,急性经口毒性试验中,雌雄大鼠的LD 50均大于5000 mg·Kg^(-1),并且给药组雌雄大鼠的心脏几乎没有受到影响,肾脏受到轻度影响,肝脏受到一定的损伤,出现肝细胞点状坏死等。亚慢性经口毒性试验中,与对照组雌雄大鼠相比,中、高剂量组雌雄大鼠血清中谷丙转氨酶、谷草转氨酶含量均显著升高(P<0.05或P<0.01),高剂量组雌性大鼠血清中总胆红素含量显著升高(P<0.05);病理组织切片分析结果表明,三个给药组雌雄大鼠的心脏和肾脏几乎没有受到影响,但中、高剂量组雌雄大鼠的肝脏受到一定的损伤,出现肝细胞点状坏死等;氧化应激实验分析结果表明,与对照组雌雄大鼠相比,中剂量组雌雄大鼠肝脏中丙二醛含量显著升高(P<0.05),高剂量组雌雄大鼠肝脏中诱导型一氧化氮合成酶含量显著升高(P<0.01),进一步证实了中、高剂量组雌雄大鼠的肝脏受到了损伤。

白果种仁正丁醇萃取部位的化学成分研究

目的:对白果种仁的正丁醇部位进行系统的化学成分研究。方法:采用大孔树脂、MCI、Sephadex-LH凝胶,制备色谱等多种色谱相结合的方法,对白果正丁醇层萃取物进行分离纯化,通过多种波谱数据进行结构鉴定。结果:从白果的正丁醇层萃取物部位分离并鉴定了6个单体化合物,分别为,adenine(1),adenosine(2),Ginkgolide B(3),Ginkgolide C(4),MPN(5),MPN-5′-glu(6)。

白果仁及炒白果仁内源性有害成分分析

以白果仁、炒白果仁为试验材料,采用HPLC法测定总银杏酸,色谱柱为YMC-Triart C18(4.6mm×150mm,5μm),流动相为0.1%三氟乙酸的乙腈溶液-0.1%三氟乙酸的水溶液,检测波长为310nm,流速为1.0mL/min;采用HPLC法测定4′-O-甲基吡哆醇(MPN)和4′-O-甲氧基吡哆醇-5′-葡萄糖苷(MPNG),色谱柱为YMC-Triart C18(4.6mm×150mm,5μm),流动相为甲醇-去离子水,检测波长为328nm,流速为1.0mL/min。采用顶空气相色谱(HS-GC)法对氢氰酸进行限度检查。结果表明,总银杏酸的平均回收率为101.17%、RSD为4.57%(n=6)、定量限为12.18ng、检测限为4.87ng;MPN平均回收率为103.14%、RSD为4.80%(n=6)、定量限为5.94ng、检测限为2.38ng;MPNG平均回收率为103.54%、RSD为3.05%(n=6)、定量限为11.20ng、检测限为4.48ng;氢氰酸定量限为10ng、检测限为3.5ng。建立的方法专属性强、重复性好,灵敏度高,可用于白果仁、炒白果仁中内源性有害成分的检测。

CaCl_(2)调节银杏果分离蛋白/果胶复合凝胶质构特性

将CaCl_(2)加入质量浓度为120 g/L银杏果分离蛋白(GSPI)水溶液及质量浓度为5 g/L果胶(酯化度分别为38%和76%)水溶液中,使Ca^(2+)最终质量浓度分别为0.05、0.11和0.22 g/L,基于此溶胶制备热诱导GSPI/果胶复合凝胶。采用粒径和ζ-电位法、流变学及质构学、SDS-PAGE、FTIR和SEM测试了溶胶的物化性质、成胶过程及复合凝胶的功能性和微观结构,探讨了Ca^(2+)对蛋白/果胶复合凝胶性能的影响及其潜在的机制。结果表明,添加Ca^(2+)降低溶胶粒径,但不改变其带电量;降低溶胶流变学特性,破坏复合凝胶形成;进而弱化凝胶质构特性,但对其持水性无显著影响。Ca^(2+)破坏蛋白与果胶间的作用,竞争性地与果胶结合。随着Ca^(2+)质量浓度的增加,以上效应表现更显著。相比之下,高酯化度果胶比低酯化度果胶对Ca^(2+)更为敏感。

γ-氨基丁酸/L-瓜氨酸增强白果分离蛋白凝胶性

以白果分离蛋白(GSPI)为成胶基质材料,将γ-氨基丁酸(GABA)和L-瓜氨酸(L-Cit)分别加入到GSPI水溶液中,均质后再将溶液pH分别调至5.0、6.0和7.0,制备了热诱导凝胶。采用物化分析法、机械力学、蛋白凝胶电泳、SEM及FTIR表征了溶胶的物性、凝胶性和微观结构,并探讨GABA、L-Cit对GSPI凝胶性能的影响及其机制。结果表明,GABA、L-Cit对GSPI溶解度无提升作用,但能显著降低蛋白疏水性;GABA促进溶胶聚集并降低其ζ-电位,而L-Cit在pH 7.0时则促进解聚和提高ζ-电位;两者均能促进蛋白分子疏水基团向内折叠。在pH5.0和pH7.0时,以上两种氨基酸特别是L-Cit显著提高蛋白凝胶性能,而在pH6.0时则弱化凝胶性能。其影响机制可能是氨基酸与GSPI之间的静电作用,而这种效应依赖于所在体系的pH。

银杏无性系种实的无胚现象及其主要成分比较分析

【目的】全面测定银杏无性系种实的无胚率以及有胚、无胚种实的主要成分,筛选出无胚率高的银杏无性系种质资源,深入研究种实无胚现象出现的原因与机制,为银杏产业资源的进一步开发利用提供参考。【方法】于江苏省徐州市邳州国家银杏良种基地随机采集47个无性系雌株种实,抽样后逐一剥开,开展无胚现象调查,计算无胚率。根据国家和行业相关标准,区分银杏无胚种实、有胚种实,并分析其主要成分。【结果】47个银杏无性系的无胚率在17.16%~100%之间,平均59.74%,中位数59.02%,方差分析发现无性系之间的无胚率差异显著。银杏无性系的果形指数在1.19~1.81之间,果形指数与无胚率存在显著性相关,相关系数为-0.285。选择12个无性系测定发现,无胚银杏种实的脂肪、可溶性糖、淀粉、可溶性蛋白、总氨基酸、总黄酮、萜内酯含量与有胚银杏种实差异不显著,银杏毒、Ca、Fe含量显著低于有胚种实。无胚率与淀粉、萜内酯含量均有较强相关性,相关系数分别为0.698、-0.599。【结论】从胚性有无角度深化对银杏种实加工利用的科学认识,发现银杏主要无性系胚性关系,找到无胚率90%以上或完全无心的银杏种质资源,区分无胚、有胚种实,分析其主要营养成分、矿物质和主要次生代谢产物的成分差异及其与胚性的关系,证实银杏无胚率与其淀粉含量呈极显著正相关,与其萜内酯含量呈显著负相关等,为银杏果业开发提供更精准的科技支撑。

白果蛋白质的分离、纯化、理化特性及其抗氧化活性研究

选用江苏省泰兴市大佛指白果为原料,采用盐溶和盐析的方法,从白果中分离制备出清蛋白(GAP)、球蛋白(GGP)和盐溶蛋白(GSP)。白果蛋白中以清蛋白和球蛋白为主,醇溶蛋白、碱溶蛋白和复合蛋白含量很少。化学成分分析表明,制得的GAP、GGP和GSP中以GAP的蛋白质纯度高,氨基酸组成丰富、合理,属于优质蛋白质。活性试验结果表明GAP的抗氧化活性远高于GGP。

高静压处理改善白果蛋白致敏性和功能特性

为了研究高静压处理对白果蛋白结构、抗原性及功能特性的影响,分别采用100,200,300,400,500,600和700 MPa的压力对白果蛋白进行处理,采用酶联免疫吸附检测法测定蛋白的致敏性,分别采用聚丙烯酰胺凝胶电泳,圆二色谱,荧光光谱和紫外吸收光谱检测白果蛋白分子量和构象的改变,功能特性的检测包括热稳定性和乳化特性。结果表明,高静压处理在300~700 MPa范围内可显著降低白果蛋白的致敏性(P<0.05),同时高压处理后,白果蛋白能被分解为分子量为4~30 k Da范围内的小分子蛋白,此外,其二级结构中的α-螺旋和β-折叠结构被大量破坏形成无规则卷曲结构,其紫外吸收强度,表面疏水性和游离巯基含量明显提高(P<0.05),高压对白果蛋白的致敏性影响与其结构变化密切相关,另外高压处理(300~700 MPa)可明显改善白果蛋白的热稳定性和乳化性能(P<0.05)。因此,高静压技术可以作为一种降低白果蛋白致敏性和改善其功能特性的有效手段。

中国银杏的种核类型及其特征

银杏种内变异较大。 2 0世纪 5 0年代起 ,通过广泛调查、收集我国银杏的核用品种资源 ,对种实不同发育时期的组织结构及形态特征进行了解剖观察。主要根据种实的珠托、种核的形状、长、宽、厚及种核两侧、顶端的特征 ,将银杏种核分为长子、佛指、马铃、梅核、圆子 5种类型 ,并确定了隶属于各个类型的主要栽培品种。通过对每一类型的种核重、核形指数及种仁中干物质、直链淀粉、支链淀粉、淀粉、粗蛋白、可溶性糖、氢氰酸含量的分析 ,对种核品质作了鉴评 ,为银杏核用品种资源的利用和改良提供了依据。

白果蛋白质提取及SDS-PAGE分析

以白果为原料,采用不同的原料处理及蛋白质提取方法,运用单因素和正交设计的方法,以料液比、提取时间、提取液浓度、提取液pH值为考察因素,研究白果蛋白质提取的最佳工艺条件,并对提取的白果蛋白进行SDS-PAGE凝胶电泳分析。结果表明:经过冷冻干燥处理的白果采用Tris-HCl提取法获得的白果蛋白含量较高;Tris-HCl法提取白果蛋白的最佳工艺为pH8.5、0.15mol/L Tris-HCl溶液、料液比1:20(g/mL)、提取时间4h,白果蛋白质的提取率达到75.01%。白果蛋白SDS-PAGE分析表明,白果蛋白中约含13条亚基,主要为21kD和32kD的两种亚基,白果蛋白的亚基主要集中在31～100kD,占亚基总数的77%。