陈年普洱茶香气成分及清除DPPH自由基活性研究

为研究陈年普洱茶的特征风味成分及生物活性,采用顶空-固相微萃取-气质联用法测定了3种陈年普洱茶中挥发性物质,结合质谱和保留指数共鉴定出57种化合物,其中甲氧基酚类、醇类及酮类化合物为主要香气成分。同时采用比色法测得3种普洱茶的沸水提取物的茶多酚含量分别为(41.91±1.98)、(43.84±2.56)及(41.28±2.57) mg GAE/(g·DW),并对3种普洱茶的1,1-二苯基苦基苯肼(DPPH·)自由基清除效果进行研究。结果表明3种普洱茶均具有较好的清除DPPH自由基能力,且呈剂量依赖性,测得3种普洱茶提取物清除DPPH·自由基的IC₅₀分别为(129.03±0.25)、(139.47±1.58)及 (152.57±3.34) mg GAE/L。     

马蓝次生代谢产物研究进展

马蓝是一种常用的道地药材,地下根茎与根常作为生产板蓝根及制剂的原料,具有多种药效功能。药用植物中有效成分大多数为植物次生代谢产物,但当前就马蓝次生代谢方面的研究却鲜有报道。本研究以植物的次生代谢为出发点,结合马蓝目前已经报道的药效成分研究现状,着重从酚类、萜类、含氮化合物3种次生代谢产物对马蓝次生代谢产物研究概况进行阐述,旨在为马蓝药效成分形成的分子机制研究提供理论基础,为进一步开展马蓝种质创新工作奠定基础。     

麦秸还田耕层酚酸变化及其对夏玉米生长的影响

对大田条件下麦秸腐解过程中产生的主要化感物质酚酸的 变化及其对夏玉米吸肥量和产量的影响研究结果表明，秸秆还田可增加土壤中酚酸浓度，秸杆还田后酚酸产生的高峰期在翻埋后40d左右，施N、P化肥处理的土壤中酚酸含量较低，酚酸对夏玉米幼苗根系的生长有明显抑制作用，而对玉米产量及肥料吸收利用的影响不显著。     

Soil volatile fungistasis and volatile fungistatic compounds

Fungistasis is a widespread phenomenon that can be mediated by soil microorganisms and volatile organic compounds (VOCs). The relationship between soil microorganisms and VOCs is still unclear, however, and many fungistatic compounds remain to be identified. We assessed the effects of soils (soil direct fungistasis) and VOCs produced by natural soils (soil volatile fungistasis) on the spore germination of several fungi. Both strong soil direct fungistasis and soil volatile fungistasis were observed in a wide range of soils. Soil fungistasis and VOC fungistasis were significantly correlated (P<0.001). The volatile fungistatic activity of soils stopped after autoclaving. Some VOCs were identified by using solid-phase microextraction-gas chromatography/mass spectrum. VOC composition and in vitro antagonism of relatively pure commercial compounds also were measured. Some VOCs, trimethylamine, 3-methyl-2-pentanone, dimethyl disulfide, methyl pyrazine, 2,5-dimethyl-pyrazine, benzaldehyde, N,N-dimethyloctylamine and nonadecane, were produced by various fungistatic soils. Moreover, antifungal activity test of above VOCs showed that trimethylamine, benzaldehyde, and N,N-dimethyloctylamine have strong antifungal activity even at low levels (4-12 mg l⁻¹).     

柑橘果实酚类物质及其生物活性研究进展

柑橘果实富含酚类物质,主要包括类黄酮和酚酸,其中以类黄酮为主。本文围绕柑橘果实酚类物质的种类、含量与分布、动态变化,生物活性等对相关研究成果进行了综述,旨在为柑橘果实的科学利用提供信息。     

不同种类柑橘果实氨基酸组成及营养品质评价

为探明不同品种宽皮柑橘果肉的特征性香气物质,以芦柑、温州蜜柑、红桔、瓯柑、砂糖橘的果肉为研究对象,基于GC-MS共分离鉴定出65种香气物质,其中d-柠檬烯含量最高占56.34~85.98%。采用香气活性值法和主成分分析法,确定温州蜜柑的特征香气物质为反式-β-罗勒烯、(E)-2-壬烯醛、橙花醛、香叶基丙酮,红桔为香叶醛、(-)-4-松油醇、α-萜品烯、辛醛、α-萜品醇、芳樟醇、β-香茅醇、β-月桂烯、?-萜品烯,瓯柑为顺式-β-罗勒烯、d-柠檬烯、β-水芹烯,砂糖橘为β-香茅醛、癸醛、紫苏醛、(E)-2-己烯醛,而芦柑仅有α-金合欢烯。这些特征香气性物质的差异,形成宽皮柑橘独特的风味特征。     

Comprehensive lipidomics and volatile compounds profiling reveals correlation of lipids and flavors in DHA-enriched egg yolk

DHA-enriched eggs have gained popularity due to their unique nutritional value, but their flavor can be challenging for some consumers to accept. The study analyzed the correlation of lipids and flavors in DHA-enriched egg yolks using comprehensive lipidomics and volatile compound analysis. The results showed that 411 lipids were detected in two egg yolk samples. Among them, 148 lipid species, including 48 DHA-containing lipids, were significantly higher in DHA-enriched egg yolks than in Common ...     

鄂通两头乌与通城猪肌肉中重要营养风味物质的比较

为比较鄂通两头乌与通城猪肌肉营养和风味物质的差异,分别对两群体背最长肌中氨基酸、脂肪酸、肌苷酸和硫胺素4类营养风味物质进行测定和分析。结果显示:通城猪肌肉氨基酸种类齐全,16种氨基酸总量为(19.42±1.31) g/100 g,必需氨基酸含量为(8.47±0.98) g/100 g,主要鲜味氨基酸含量为(6.80±0.46) g/100 g;脂肪酸种类丰富、营养风味价值高,饱和脂肪酸含量为43.04%±1.84%,不饱和脂肪酸含量为56.96%±1.84%,其中单不饱和脂肪酸含量为47.47%±2.63%,多不饱和脂肪酸含量为9.50%±2.50%,亚油酸含量达8.93%±2.36%。而其风味物质硫胺素和肌苷酸的值分别为(0.23±0.05) mg/100 g、(3.23±0.67) mg/g。鄂通两头乌肌肉中多不饱和脂肪酸(12.08%±4.72%)、亚油酸(11.36%±4.44%)和硫胺素((0.23±0.05) mg/100 g)显著或极显著高于通城猪,上述其他性状与通城猪差异不显著(P0.05)。以上结果表明:鄂通两头乌和通城猪的猪肉均具有高营养价值和独特风味等特点,而且鄂通两头乌除保留了通城猪肉的营养风味外,多不饱和脂肪酸、硫胺素含量更高,值得进一步开发利用。     

紫丁香鲜花香气化学成分的研究

采用固相微萃取吸附采集紫丁香Syringa oblata鲜花的香气成分,用色谱/质谱联用分析鉴定,并用GC/MS总离子流色谱峰的峰面积归一化法对紫丁香鲜花的挥发性成分进行定量分析。结果鉴定出大香叶烯-D(22.37%)、β-波旁烯(15.97%)、苯甲醛(11.03%)、β-石竹烯(7.56%)、β-古芹烯(3.43%)、芳樟醇(3.18%)、丁香醛B(2.99%)、α-胡椒烯(2.70%)、β-苯乙醇(2.39%)、苯乙醛(1.99%)、苯甲醇(1.89%)、丁香醇B(1.87%)、α-愈创木烯(1.49%)、丁香醛A(1.46%)、α-蒎烯(1.39%)、丁香醇A(1.03%)、α-草烯(1.03%)等48种化合物。其中所含的4个丁香醇异构体和2个丁香醛异构体是紫丁香鲜花的特征香气成分。固相微萃取-气相色谱/质谱法是一种可用于鲜花挥发性香气成分分析的简单可行的分析方法。图1表1参10