海南山苦茶叶的化学成分(Ⅱ)

从海南山苦茶叶中分离出10个化合物,根据理化性质的测定和波谱数据的解析,分别鉴定为3-羟基-4,5（R）-二甲基-2（5H）-呋喃酮（1）、没食子酸（2）、（6S,9R）-6-羟基-3-酮-α-紫罗兰醇-9-O-β-D-葡萄糖苷（3）、aviculin（4）、（＋）-lyoniresinol 3α-O-α-L-rhamnopyranoside（5）、（Z）-3-己烯醇-β-D-葡萄糖苷（6）、3,4,8,9,10-五羟基-二苯并[b,d]吡喃-6-酮（7）、木栓醇（8）、β-谷甾醇（9）和木栓酮（10）,其中化合物4、5为首次从该属植物中获得。     

SDE-GC-MS法分析三种虫生真菌菌丝中挥发性成分

采用同时蒸馏萃取-气相色谱质谱联用（SDE-GC-MS）的方法分析了蝉拟青霉、拟细羽束梗孢、根足被毛孢菌丝的挥发性成分,从中分别鉴定出44、28和19种化合物,它们主要为萜类化合物、芳香族化合物、醇类、烷烃类、酯类和醛类。成分比较发现,3种虫生真菌挥发性物质中有3种主要共有成分,分别为丁羟基甲苯、1-辛烯-3-醇、苯乙醛。除共有成分外,它们各自都有大量特有成分,其中蝉拟青霉主要有5-甲基-2-呋喃-乙酸酯、反式-2,4-癸二烯醛、长叶烯等;拟细羽束梗孢主要有5-羟基-2-癸烯酸-δ-内酯、2,4-二甲基-恶唑、苯酚、β-榄香烯等;根足被毛孢主要有3,4,5-三甲基-苯甲醛、1,3-二甲基-3,4,5,6-四氢化-2(1H)嘧啶、顺式-2-羟基-1-（羟甲基）-9-十八碳一烯酸乙酯。     

花生中香味成分的研究与分析

笔者通过分析花生中香味成分化合物来对花生中香味成分进行研究。采用的方法为固相微萃取法,此法可以萃取出烘烤花生中的各种风味物质,根据实验我们可以看出:烘烤花生中挥发性的化合物中FD因子的最大值为256,并且FD因子排在前三位(FD因子>64)的在实验中检测出有10种已知的化合物和3种未知的化合物,实验结果显示:已知的化合物分别为:3-甲基丁醛(巧克力味)、2-甲基丁醛(焦糖味)、2-(2-羟乙基)-3-甲基-4-噻唑(鱼腥味)、2,5-二甲基吡嗪(烘烤坚果味)、2,6-二甲基吡嗪(烘烤坚果味)、乙基吡嗪(爆米花味)、2-乙基-5-甲基吡嗪(草味,坚果味)、呋喃醛(生土豆味)、3-乙基-2,5-二甲基吡嗪(咖啡味)、苯乙醛(甜芳香味)等。通过本次的实验,可以得出结论:2,5-二甲基吡嗪、乙基吡嗪等吡嗪类和醛类化合物是花生中香味的主要成分,对花生散发香味的贡献最大,酮类化合物对花生的风味贡献率较醛类来讲较低。     

粤北乳菇属的种类的研究

1984-1985年作者在广东北部山区采集了乳菇属Lactarius DC ex S.F.Gray的19个种,其中1个新种;多鳞乳菇Lactarius squamu-losus Bi et Li sp.nov.以及8个国内新记录。并附分种检索表。     

中国热带和亚热带地区乳菇属的5个新种及1个新记录种

通过形态学比较和对ITS-nrDNA序列的分析,本文描述了产自我国热带及亚热带地区乳菇属的5个新种和1个中国新记录种。新种缘囊体乳菇Lactarius cheilocystidiatus和多囊体乳菇L. polycystis由于具有真正的囊状体而与变红乳菇亚属L. subg. Plinthogalus的绝大多数种相异,它们与泰国的L. crassiusculus关系密切。新种粘果乳菇L. gloeocarpus和多见乳菇L. vulgaris是乳菇亚属L. subg. Lactarius的新成员,其典型特征为淡黄色胶粘菌盖、孢子具网状纹饰和较大的囊状体,它们与原初描述自中国的淡黄褐乳菇L. pallido-ochraceus、淡环纹乳菇L. pallidizonatus以及印度的L. thindii形成种复合群。新种湖南乳菇L. hunanensis与温带物种具有较强的亲缘关系,它的典型特征为粘不规则交织型的盖表皮中具橄榄色被壳物质以及具斑马纹纹饰的孢子,属L. blennius种复合群。南方窝柄黄乳菇L. austroscrobiculatus原初描述自印度尼西亚,具有强烈的热带性质,这是在中国首次发现该种。本研究的标本采集自安徽、海南、河南、湖南、江西和云南。这些物种是中国-日本森林植物亚区的代表性乳菇类真菌。     

蛹虫草培养液成分研究

目的：研究蛹虫草培养液的化学成分。方法：采用硅胶柱色谱等技术分离纯化单体化合物,并根据理化性质及光谱数据鉴定结构。结果：分离并鉴定了8个化合物,分别是2-乙基-3-羟基4H吡喃酮（1）、1-甲酰基-苯并咪唑（2）、3-乙基-4-羟基-6-甲基．2H．吡喃-2-酮（3）、1-甲基-6-异丁基-2,5-哌嗪二酮（4）、1-异丙基-6-异丁基-2,5-哌嗪二酮（5）、3,6-二（对羟基苄基）-2,5-哌嗪二酮（6）、1-羟甲基-6-异丁基-2,5-哌嗪二酮（7）、麦角甾-7-22-二烯-3β,5α,6β-三醇（8）。结论：化合物1-5,7为首次从虫草属真菌中分离得到。     

色钉菇子实体化学成分及其生物活性初探

从色钉菇Chroogomphus rutilus子实体中分离纯化出11种化合物,经核磁等方法鉴定为：（1）麦角甾-7,22-二烯-3-酮;（2）麦角甾-4,6,8(14), 22-四烯-3-酮;（3）邻苯二甲酸二丁酯;（4）顺式-3-己烯醇;（5）3β,5α,6β-三羟基麦角甾-7,22-二烯;（6）α-甜没药醇;（7）2-甲氧基腺嘌呤核苷;（8）(4E,8E)-2-N-(2-羟基棕榈酰)-1-O-B-D-吡喃葡萄糖基-9-甲基-4, 8-sphingadienine;（9）5-羟基尿嘧啶核苷;（10）2-氨基-3-醛基-6-甲氧基吡啶;（11）Polyozellin。对分离化合物的体外抗氧化、抗肿瘤活性的初步测定结果显示,2-甲氧基腺嘌呤核苷、顺式-3-己烯醇表现出较强的清除DPPH自由基活性,EC50值分别为0.06128mg/mL和0.08253mg/mL。5-羟基尿嘧啶核苷对人胃癌细胞株BGC的增殖有较强的抑制作用,IC50值为7.92μg/mL。研究结果为进一步开发利用色钉菇提供了科学依据。     

顶空气相色谱-质谱联用法分析灵芝发酵物中的挥发性物质

采用顶空-气相色谱-质谱联用法对灵芝发酵物的风味物质进行了定性和定量测定。结果表明,灵芝发酵物中至少含有31种风味物质。对其中21种主要成分进行了鉴定,这些物质大多是酮类、醇类和内酯类化合物。所有物质中4,5-二氢-3,5-二甲基-2-呋喃酮的含量最高,达64.12%。此外,3-戊烯-2-酮和戊基乙烯基原醇是已知的食品香料成分。结果有助于初步理解灵芝发酵物产生清淡香味的原因。     

顶空气相色谱-质谱联用法分析灵芝发酵物中的挥发性物质

采用顶空-气相色谱-质谱联用法对灵芝发酵物的风味物质进行了定性和定量测定。结果表明,灵芝发酵物中至少含有31种风味物质。对其中21种主要成分进行了鉴定,这些物质大多是酮类、醇类和内酯类化合物。所有物质中4,5-二氢-3,5-二甲基-2-呋喃酮的含量最高,达64.12%。此外,3-戊烯-2-酮和戊基乙烯基原醇是已知的食品香料成分。结果有助于初步理解灵芝发酵物产生清淡香味的原因。     

黄花石蒜中的黄酮类成分

通过对黄花石蒜（Lycoris aurea）乙醇提取物的乙酸乙酯溶解部分进行分离纯化,得到7个化合物.经物理方法和波谱分析,分别鉴定为（2S）-4＇-羟基-7-甲氧基黄烷（1）、（2S）-3＇,7-二羟基-4＇-甲氧基黄烷（2）、（2S）-4＇,7-二羟基黄烷（3）、（2S）-4＇,7-二羟基-8-甲基黄烷（4）、（2S）-4＇,7-二羟基-3＇-甲氧基-8-甲基黄烷（5）、（2S）-4＇,5,7-三羟基-8-甲基黄烷酮（6）、2,4＇-二羟基-4-甲氧基二氢查尔酮（7）.所有化合物均为首次从该属植物中分离得到,另外,本文首次归属了化合物5、6、7的13C NMR信号.     

Aroma compounds in Japanese sweet rice wine (Mirin) screened by aroma extract dilution analysis (AEDA)

Thirty-nine key aroma compounds were newly identified or tentatively identified in the aroma concentrate of Japanese sweet rice wine (Mirin) by an aroma extract dilution analysis technique based on the 68 detected peaks. Among them, 3-(methylthio)propanal, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 3-methylbutanoic acid, 2-methylbutanoic acid, and 2-methoxy-4-vinylphenol were detected with the highest FD factors in this study.     

Identification of 4,5-Dimethyl-3-hydroxy-2(5H)-furanone (Sotolon) and Ethyl 9-Hydroxynonanoate in Botrytised Wine and Evaluation of the Roles of Compounds Characteristic of It

Two new components of botrytised wine were identified: 4,5-dimethyl-3-hydroxy-2(5H)-furanone (Sotolon) and ethyl 9-hydroxynonanoate. Sotolon, the key substance of cane sugar aroma, was identified as the sugary flavor substance of botrytised wine by means of gas chromatography-mass spectrometry after column chromatographic separation on DEAE-Sephadex and silica gel. Ethyl 9-hydroxynonanoate was identified by chemical ionization and electron impact mass spectrometry. To evaluate the role of 17 volatile and 5 nonvolatile compounds characteristic of botrytised wine, these compounds were added to a normal wine. This produced a sweet, honey-like flavor similar to that of botrytised wine. The importance of Sotolon and the role of each group of flavor substances in producting this flavor was clarified by omission tests.     

The naturally occurring furanones: formation and function from pheromone to food

Three closely related 4-hydroxy-3(2H)-furanones have been found in a range of highly cooked foodstuffs where they are important flavour compounds with aroma threshold values as low as 20 micrograms kg-1 water (approximately 0.14 mumol l-1). The compounds are formed mainly as a result of the operation of the Maillard reactions between sugars and amino acids during heating but one compound, 5-(or 2)-ethyl-2-(or 5)-methyl-4-hydroxy-3(2H)-furanone, appears in practice to be produced by yeast, probably from a Maillard intermediate, during the fermentation stages in the production of soy sauce and beer. The compounds are also important in the flavour of strawberry, raspberry, pineapple and tomato but the route of biosynthesis is unknown. Two 3-hydroxy-2(5H)-furanones, emoxyfuranone and sotolon, which are produced spontaneously from amino acids such as threonine and 4-hydroxy-L-leucine are major contributors to meaty and spicy/nutty flavours in foods. The biosynthesis of 5-(1,2-dihydroxyethyl)-3,4-dihydroxy-2(5H)-furanone (ascorbic acid, vitamin C) and 5-hydroxymethyl-3,4-dihydroxy-2(5H)-furanone (erythroascorbic acid) from sugars in plants and yeast, respectively, has been characterized to the enzymic level. After treatment with chlorine, humic waters contain a range of chloro-furanones, some of which, particularly 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), are powerful mutagens. The furanones which occur in foods are also mutagenic to bacteria and cause DNA damage in laboratory tests. However, these compounds are, in practice, very effective anti-carcinogenic agents in the diets of animals which are being treated with known cancer-inducing compounds such as benzo[alpha]pyrene or azoxymethane. Two of the food-derived furanones have antioxidant activity comparable to that of ascorbic acid. A biological function has been discovered for some of the furanones besides vitamin C. 5-Methyl-4-hydroxy-3(2H)-furanone is a male pheromone in the cockroach Eurycolis florionda (Walker) and the 2,5-dimethyl derivative deters fungal growth on strawberries and is an important component of the attractive aroma of the fruit. The red seaweed Delisea pulchra (Greville) Montagne produces a range of brominated furanones which prevent colonisation of the plant by bacteria by interfering with the acylated homoserine lactone (AHL) signalling system used by the bacteria for quorum sensing. In addition, these compounds can deter grazing by marine herbivores. It is proposed here that the evolved biological function of a number of furanones is to act as inter-organism signal molecules in several different systems. This has resulted in two coincidental effects which are important for humans. Firstly, the easily oxidized nature of the furanones in general, which is likely to be an important property in their functioning as signal molecules, results in both mutagenic and anti-carcinogenic activity. The balance of these two effects from compounds in the diet has yet to be fully established. Secondly, and more specifically, the 4-hydroxy-3(2H)-furanones associated with fruit aromas act to attract animals to the fruit, which ensures seed dispersal. In the case of humans, the coincidental synthesis of some of these compounds in foods during preparation results in these foods appearing particularly attractive through the transferred operation of the original signalling mechanisms.     

Nonenzymatic formation of 4,5-dimethyl-3-hydroxy-2(5H)-furanone in foodstuffs

The mechanism of formation of 4,5-dimethyl-3-hydroxy-2/5H/-furanone in some food-stuffs was investigated. The compound was found to result from condensation of acetaldehyde under oxidative conditions. The intermediate product of the condensation is 2-oxobutanoic acid.     

热风干燥温度对荷叶离褶伞干燥特性及挥发性风味物质的影响

为探究不同热风干燥温度对荷叶离褶伞干燥特性及挥发性风味物质的影响。本研究比较了8种常见干燥动力学模型对荷叶离褶伞干燥过程拟合的适用性,采用GC-IMS技术,对不同干燥温度处理下荷叶离褶伞的挥发性风味物质进行测定。结果表明：荷叶离褶伞热风干燥为典型的降速干燥,Midilli-Kucuk模型可以较好地描述其热风干燥过程（R²>0.99791,RMSE<0.0152,χ²<2.31×10^-4）;温度对荷叶离褶伞风味物质影响显著,在5个干燥温度处理下的荷叶离褶伞中共鉴定到47种挥发性风味物质,包括醛类13种、酮类8种、醇类13种、酯类5种和其他类8种。随着干燥温度升高（55-75℃）,醛类物质相对含量呈下降趋势,而醇类、酮类以及其他物质（乙酸等）略有上升趋势。     

FaQR, required for the biosynthesis of the strawberry flavor compound 4-hydroxy-2,5-dimethyl-3(2H)-furanone, encodes an enone oxidoreductase

The flavor of strawberry (Fragaria x ananassa) fruit is dominated by an uncommon group of aroma compounds with a 2,5-dimethyl-3(H)-furanone structure. We report the characterization of an enzyme involved in the biosynthesis of 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF; Furaneol), the key flavor compound in strawberries. Protein extracts were partially purified, and the observed distribution of enzymatic activity correlated with the presence of a single polypeptide of approximately 37 kD. Sequence analysis of two peptide fragments showed total identity with the protein sequence of a strongly ripening-induced, auxin-dependent putative quinone oxidoreductase, Fragaria x ananassa quinone oxidoreductase (FaQR). The open reading frame of the FaQR cDNA consists of 969 bp encoding a 322-amino acid protein with a calculated molecular mass of 34.3 kD. Laser capture microdissection followed by RNA extraction and amplification demonstrated the presence of FaQR mRNA in parenchyma tissue of the strawberry fruit. The FaQR protein was functionally expressed in Escherichia coli, and the monomer catalyzed the formation of HDMF. After chemical synthesis and liquid chromatography-tandem mass spectrometry analysis, 4-hydroxy-5-methyl-2-methylene-3(2H)-furanone was confirmed as a substrate of FaQR and the natural precursor of HDMF. This study demonstrates the function of the FaQR enzyme in the biosynthesis of HDMF as enone oxidoreductase and provides a foundation for the improvement of strawberry flavor and the biotechnological production of HDMF.     

Effects of the amino-carbonyl reaction of ribose and glycine on the formation of the 2(or 5)-ethyl-5(or 2)-methyl-4-hydroxy-3(2H)-furanone aroma component specific to miso by halo-tolerant yeast

The formation of HEMF[2(or 5)-ethyl-5(or 2)-methyl-4-hydroxy-3(2H)-furanone], the aroma component specific to miso and soy sauce, was promoted by cultivating the halo-tolerant yeast, Zygosaccharomyces rouxii, in a medium including the amino-carbonyl reaction products based on ribose and glycine. The glucose concentration in the medium influenced the HEMF formation by Z. rouxii.