‘福眼’和‘东壁’龙眼果实贮藏性与采后品质变化比较

比较研究了福建省主栽品种‘福眼’和‘东壁’龙眼果实在(8±1)℃、85％相对湿度条件下贮藏的果实贮藏性和品质变化差异.结果表明:与‘福眼’龙眼相比,‘东壁’龙眼果实贮藏性较好,采后贮藏期间的‘东壁’龙眼果实好果率较高,而果实失重率、果皮褐变指数、果肉自溶指数、果肉褐变度较低.采收当天的‘东壁’龙眼果实的果肉可溶性固形物(TSS)、总糖和维生素C含量都高于‘福眼’龙眼.采后贮藏期间,‘东壁’龙眼果实的果肉TSS、可滴定酸、维生素C和总糖含量的变化比‘福眼’龙眼果实少;在同一贮藏时间,‘东壁’龙眼果实的果肉TSS、维生素C和总糖含量都高于‘福眼’龙眼果实.因此认为,‘东壁’龙眼果实的贮藏性较好.     

“吉禄”芒果果实采后香气成分的组成及其变化

为了解芒果果实香气成分采后不同时期的变化特点,采用静态顶空固相微萃取技术提取“吉禄”芒果果实采后第3、6 、9 d的香气成分,运用气相色谱-质谱联用仪进行测定分析。结果表明：“吉禄”芒果果实在采后3个时期共检测到36种香气成分,主要成分为单萜烯类和倍半萜烯类。果实采后第3、6、9 d,单萜烯类化合物含量分别为89.47％、88.48％和92.71％,倍半萜烯类化合物含量分别为3.44％、5.86％和4.63％。1R-α-蒎烯是“吉禄”芒果成熟果实的特征香气成分,采后第9天的相对含量达到79.74％。     

橄榄发育过程中风味物质的变化规律

通过对‘长营’橄榄及其芽变品种‘清榄1号’果实发育过程中风味物质含量,包括可溶性固形物、可溶性糖、可滴定酸、单宁、黄酮、多酚的测定,初步探讨橄榄果实风味形成机理。结果表明:(1)供试橄榄果形整齐,品种间糖、酸物质含量变化整体一致,酚类物质差异大。(2)花后50~110 d,橄榄果实体积增大,风味物质积累,其中,‘清榄1号’酚类物质在花后70~90 d出现小幅度降低;(3)花后110~170 d,橄榄果实可溶性固形物与糖含量积累,其他风味物质含量降低。(4)‘长营’花后110 d采收风味较佳,‘清榄1号’花后170 d采收风味佳。研究表明,橄榄果实风味形成与糖酸等物质关系不大,与酚类物质关系密切,花后110 d为研究橄榄风味形成的关键时期。     

贵州主栽杧果品种果实品质及香气成分分析

为了解贵州主栽杧果品种的果实品质特性,分析了‘金煌杧’‘贵妃杧’‘玉文杧’‘桂七杧’‘红玉杧’5个主栽杧果品种果实的12个品质指标和香气成分。结果表明：5个杧果品种的平均单果重在380~898 g,果形指数在1.60~2.14,可食率72.10%~77.74%,水分含量82.06%~85.10%,总灰分含量1.30%~1.70%,粗纤维含量在0.90%~1.10%,可溶性糖含量在7.75~13.90 g/100 g,可溶性固形物含量在11.05%~17.10%,总酸含量在0.120~0.233 g/100 g,维生素C含量在0.0018~0.0073 g/100 g,糖酸比在40.26~123.88,固酸比在61.30~153.39;5个杧果品种共检测出50种香气成分,以萜烯类化合物为主;‘金煌杧’‘贵妃杧’‘玉文杧’‘桂七杧’‘红玉杧’分别检测出香气组分14种、14种、21种、21种、16种,其中萜烯类化合物的含量分别达56.34%、73.95%、82.47%、97.32%、64.16%。5个杧果品种的香味均以松木香味为主,略带青香、苹果香和柠檬香等香味。     

绿茶品种中糖甙键合态单萜烯醇的含量分布及季节变化

茶鲜叶中糖甙键合态单萜烯醇类是成茶香气的重要物质基础。通过葡糖甙水解酶的作用可释放出香气主要成分单萜烯醇类化合物。各品种茶树鲜叶制得的成茶香气风格存在差异,不同季节的茶叶香气也有明显的不同。这些差异很大程度上是由于单萜烯醇的前体物含量及各品种茶树糖甙水解酶特性的不同而引起的。因此,通过研究各品种及季节的键合态单萜烯醇含量变化,对选育高香茶树品种具有重要的意义。 材料与方法 (一)材料 各绿茶品种鲜叶蒸青样均取自中国农业科学院茶叶研究所品种圃,春、夏、秋三季统一采摘一芽二叶样。 (二)方法 1.糖甙键合态单萜烯醇的提取和分析按     

不同保鲜薄膜袋包装对建阳桔柚贮藏保鲜效果的影响

以杂柑类新品种—‘建阳桔柚’果实为材料,研究微孔薄膜袋(WK微孔)、打孔薄膜袋(DK打孔)和无孔薄膜袋(CK对照)包装对‘建阳桔柚’果实在(10±1)℃下贮藏120 d保鲜效果的影响。结果表明,与无孔薄膜袋包装相比,微孔薄膜袋和打孔薄膜袋包装能使采后‘建阳桔柚’果实包装袋内保持较高的O_2含量和较低的CO_2含量,有利于维持‘建阳桔柚’果实进行低水平有氧呼吸,显著减少因无氧呼吸造成的果肉乙醇积累,保持较高的‘建阳桔柚’果肉可溶性固形物、可滴定酸、维生素C和类胡萝卜素含量,显著提高果实好果率,降低果实失重率、感病指数和枯水指数;并且微孔薄膜袋包装对‘建阳桔柚’的贮藏保鲜效果更优于打孔薄膜袋。     

香蕉果实发育成熟过程中多酚物质的变化规律

以3个香蕉品种‘巴西蕉’‘粉蕉’‘皇帝蕉’为供试材料，利用福林酚法测定其整个生育及成熟期果皮、果肉的多酚含量，探索不同香蕉品种在发育成熟过程中的多酚含量变化规律，及其与果实发育成熟的关系。结果显示，在香蕉果实整个生育期，多酚物质含量果皮均大于果肉。多酚物质在香蕉果皮、果肉生长发育期迅速积累，到采收期下降，采后果皮多酚物质含量随着成熟度的增加而增加，而果肉多酚物质基本维持不变。用外源乙烯和1-MCP处理后发现，与对照果实相比，乙烯促进其多酚物质的积累，而1-MCP抑制其积累。     

36 个石榴（Punica granatum L.）品种的品质测定

对云南省蒙自县石榴品种园中来源于全国石榴产区的 36 个石榴（Punica granatum L.）品种, 在相同栽培条件, 相同树龄, 均达到成熟的果实进行可溶性糖含量、 有机酸含量、 可溶性固形物含量、 籽粒硬度等指标进行测定与分析。 结果表明： ‘天红蛋’ 等 29 个石榴品种中达到优良, 适合在蒙自栽培发展; ‘净皮甜’ 等 9 个品种适合作为水果鲜食类在当地栽培; ‘酸绿籽’ 等 8 个作为有机酸含量高的酸石榴品种, 适合作为药用类在当地栽培。 结果为当地石榴栽培品种的选择奠定了基础。     

红肉番石榴(Psidium guajava L.)果实香气物质的研究

利用顶空固相微萃取结合气相色谱质谱联用技术分析了红肉型‘四季桃’番石榴果实中的挥发性组分及其特征香气组分。‘四季桃’番石榴果实达到可食成熟度时,果皮呈现为黄绿色,果肉为红色;在‘四季桃’番石榴果实中共检测出醇类、醛类、酯类、萜类及酸类共62种挥发性物质;酯类物质的种类最多,共检测到24种酯类物质,但醛类物质对番石榴果实香气的贡献率最高,达到56.39%;62种挥发性组分中检测到7种特征香气组分,分别为己醛、2-己烯醛、丁酸乙酯、乙酸-3-甲基丁酯、戊酸乙酯、己酸乙酯和乙酸己酯,其中草香型的己醛和2-己烯醛及果香型特征的己酸乙酯对果实香气的贡献率较大。     

2个杧果品种果实品质及其构成研究

以红杧六号和桂热82号两个杧果品种为试材,研究其果实品质特征及其构成,结果表明:红杧六号果实单果重、可食率、类胡萝卜素含量、可滴定酸含量均高于桂热82号,而可溶性糖含量和糖酸比低于桂热82号。高效液相色谱(HPLC)分析表明,芒果果实共含3种糖、11种有机酸和4种类胡萝卜素,即果糖、葡萄糖和蔗糖;草酸、酒石酸、奎尼酸、苹果酸、抗坏血酸、乳酸、α-酮戊二酸、柠檬酸、富马酸、琥珀酸和没食子酸;堇菜黄素、β-胡萝卜素、叶黄素和番茄红素。其中,蔗糖、苹果酸和堇菜黄素分别为芒果的主要糖、有机酸和类胡萝卜素种类。两个品种果实不同糖、有机酸和类胡萝卜素组分的含量多数存在显著差异。综合而言,桂热82号的果实品质和风味较好。     

Characterization of starches of proso,foxtail, barnyard,kodo, and little millets

Scanning electron microscope (SEM) pictures of small millet starch granules showed more large polygonal and few small spherical or polygonal granules. The granules of small millets resembled those of rice starch granules. The size of the starch granules ranged from 0.8–10 m. The size of the granules was larger in barnyard millet and smaller in proso millet. Several granules showed deep indentation caused by protein bodies. SEM of starch isolated from 24 hour-germinated kodo millet showed pitting or pinholes at some points due to the attack of amylases (preferentially on bigger granules). Brabender viscoamylograph studies on small millet starches revealed that the gelatinization temperatures ranged from 75.8 to 84.9 ^° C. Barnyard millet possessed lower amylograph viscosity, minimum breakdown, and relative breakdown values when compared to the other small millets.     

Effects of application of nitrogen fertilizer on concentrations of P, K, S, Ca, Mg, Na, Cl, Mn, Fe, Cu and Zn in perennial ryegrass/white clover pastures in south-western Victoria, Australia

Effects of timing and rate of N fertilizer application on concentrations of P, K, S, Ca, Mg, Na, Cl, Mn, Fe, Cu and Zn in herbage from perennial ryegrass/white clover pastures were studied at two sites in south-western Victoria, Australia. Nitrogen fertilizer (0, 15, 25, 30, 45 and 60 kg ha^–1) was applied as urea in mid-April, early May, mid-May, early June and mid-June 1996 to pastures grazed by dairy cows. At Site 1, N fertilizer resulted in a linear increase in P, K, S, Mg and Cl concentrations in herbage and a linear decrease in Ca concentration. For all times of application, concentrations of P, K, Ca, Mg and Cl in herbage increased by 0·0048, 0·08, −0·010, 0·0013 and 0·053 g kg^–1 dry matter (DM) per kg N applied respectively. For S concentration, maximum responses occurred in mid-May (0·012 g kg^–1 DM per kg N applied). At Site 2, N fertilizer resulted in a linear increase in P, S and Na concentrations in herbage, a linear decrease in Ca concentration and a curvilinear increase in K and Cl concentration. The maximum responses for P, S and K concentrations in herbage occurred for the N application in mid-June and were 0·015, 0·008 and 0·47 g kg^–1 DM per kg N applied respectively. For Cl concentration, the maximum response occurred for the N application in early June and was 0·225 g kg^–1 DM per kg N applied. Overall, applications of N fertilizer up to 60 kg ha^–1 did not alter herbage mineral concentration to levels that might affect pasture growth or animal health.     

Milling,functional and thermo-mechanical properties of wheat,rye, triticale,barley and oat

The milling potential of hulled barley, hulled oat, triticale, rye and wheat was studied using a long tempering process and a laboratory four-roller mill. Regardless of the investigated cereal, the results indicated a significant influence (p < 0.05) of volume per surface area ratio on the milling yield and ash contents of the flour. The lowest milling yield was obtained in case of hulled oat. Solvent retention capacity profiles were determined for all investigated whole cereals and flours for predicting the contribution of different polymers to the functionality of samples. For all solvents higher values were obtained for the whole cereals compared to the corresponding flour. Thermo-mechanical properties of the whole cereals and refined flours were also investigated. If in case of wheat the gluten proteins play an essential role on dough behaviour during kneading at 30 °C, in case of triticale, rye, hulled barley and hulled oat, the fibers play a major role as well. Thermo-mechanical properties of starch registered a large variation between cereals and/or flours. The lowest torque value corresponding to starch gelatinization (C3) was registered in case of the hulled oat flour, 1.92 Nm, while the highest value in case of rye flour, 2.65 Nm.     

Structure Elucidation of New Acetylated Saponins,Lessoniosides A,B, C,D, and E,and Non-Acetylated Saponins,Lessoniosides F and G,from the Viscera of the Sea Cucumber Holothuria lessoni

Sea cucumbers produce numerous compounds with a wide range of chemical structural diversity. Among these, saponins are the most diverse and include sulfated, non-sulfated, acetylated and methylated congeners with different aglycone and sugar moieties. In this study, MALDI and ESI tandem mass spectrometry, in the positive ion mode, were used to elucidate the structure of new saponins extracted from the viscera of H. lessoni. Fragmentation of the aglycone provided structural information on the presence of the acetyl group. The presence of the O-acetyl group was confirmed by observing the mass transition of 60 u corresponding to the loss of a molecule of acetic acid. Ion fingerprints from the glycosidic cleavage provided information on the mass of the aglycone (core), and the sequence and type of monosaccharides that constitute the sugar moiety. The tandem mass spectra of the saponin precursor ions [M + Na]⁺ provided a wealth of detailed structural information on the glycosidic bond cleavages. As a result, and in conjunction with existing literature, we characterized the structure of five new acetylated saponins, Lessoniosides A–E, along with two non-acetylated saponins Lessoniosides F and G at m/z 1477.7, which are promising candidates for future drug development. The presented strategy allows a rapid, reliable and complete analysis of native saponins.     

Study of antimicrobial activity of aloevera, chitosan, and curcumin on cotton, wool, and rabbit hair

Aloevera, chitosan, and curcumin were applied in alone and in combination with each others on cotton, wool and rabbit hair by exhaustion method for the assessment of their antimicrobial activity. The antimicrobial activity of these natural ingredients was better in peroxide treated cotton, formic acid treated wool/rabbit hair fibrous substrates than their corresponding intact ones. Aloevera shown better antimicrobial activity than chitosan and curcumin when applied alone and its antimicrobial activity was enhanced by addition of both chitosan and curcumin. The application of aloevera+chitosan+curcumin combination on peroxide treated cotton and formic acid treated wool/rabbit hair fibrous substrate was fast up to twenty five washing cycles.     

酸碱条件对枯草芽胞杆菌FJAT-14254代谢物产生的影响

为考察酸碱条件对枯草芽胞杆菌FJAT-14254代谢物产生的影响,采用气相色谱-质谱联用分析枯草芽胞杆菌FJAT-14254菌株的胞内成分。结果表明：通过谱库扫描得到32种高匹配率代谢物的初步鉴定结果,主要包括氨基酸类、酸类、烷烃类等,其中含量相对较高的有7种;枯草芽胞杆菌FJAT-14254代谢物的种类和含量与其培养环境的酸碱度变化呈一定的相关性,强酸性(pH＝3)条件下培养的胞内代谢物具有特异性,而接近中性(pH＝5、7)条件及碱性(pH＝9、11)条件下培养胞内代谢物则相似。由此推断,不同pH条件影     

氮磷钾肥对稻米铁、锌、铜、锰、镁、钙含量和产量的影响

 采用田间试验，在四川省西昌市用两个水稻品种研究了氮、磷、钾肥施用量对稻米中铁、锌、铜、锰、镁、钙含量和产量的影响。结果表明，稻米中铁、锌、铜、锰、镁、钙含量均随着施氮量增加先上升后下降，滇屯502的铁、锌、铜、锰、镁、钙含量和产量都以施用90 kg/hm2 N最高，稻谷产量以施用180 kg/hm2 N最高；而合系39的铁、锌、铜、锰、镁、钙的含量以施用180 kg/hm2 N最高，稻谷产量以施用270 kg/hm2 N最高，说明供试籼型品种滇屯502对氮肥的敏感性较粳型品种合系39强；磷肥明显降低了稻米中铁、铜、锰、钙的含量和产量，适量增施磷肥有利于增加稻米中镁的含量和产量；适量施用钾肥有利于提高稻米中铁、锌、铜、锰含量和产量，两供试品种铁、锌、铜、锰含量均以90 kg/hm2 K2O时最高，而钾肥明显降低了稻米中镁、钙的含量和产量。