施用秸秆对烤烟土壤酶活性及烤烟氮和钾含量的影响

为了充分利用农作物废弃物,建立合理的资源循环系统,改善植烟土壤环境,以秦烟96为材料,采用盆栽试验,探索了秸秆施用量对烤烟土壤酶活性、烟叶和根系氮、钾含量的影响.结果表明,外施秸秆显著提高了土壤酶活性和烤烟烟叶和根系氮、钾含量.在适量范围内,随着秸秆施用量的增加,土壤酶活性和烤烟烟叶和根系氮、钾含量均呈递增趋势.     

不同移栽期对陕南烤烟氮钾含量、光合特性及经济性状的影响

为了探明陕南烟区主栽品种K326的适宜移栽期,在陕南旬阳县开展了烤烟移栽期试验研究。结果表明,随移栽期推后,各主要生育期均向后推迟,大田生育期缩短;旺长期、平顶期和成熟期烟叶氮钾、叶绿素和碳水化合物含量及净光合速率均先升高后降低,产量、均价、产值和中上等烟比率均表现出同一趋势。综合分析,依据当地气候条件特点,以旬阳试验点为代表的相同海拔区域,烤烟K326最适宜移栽期为5月10日;确定适宜移栽期可改善烟叶氮钾营养,提高光合性能,有利于干物质累积,从而提高烟叶的产量和品质。     

氮钾用量对吉林烤烟焦油释放量及重要化学性状的影响

为了明确氮钾用量对烤烟中部叶焦油释放量及其重要化学性状的影响,在吉林延边州试验点安排了两因素三水平氮钾互作试验,测定并分析了烤烟中部叶重要化学性状及烟气中焦油释放量的规律。结果表明,吉林延边地区在施N 45 kg/hm²,K₂O 180 kg/hm²时,烤烟中部叶焦油释放量最低;施氮量固定,施K₂O量在90~180 kg/hm²范围内增加,焦油释放量降低,但过量施用K₂O有使焦油释放量升高的趋势;施K₂O量固定在90 kg/hm²和180 kg/hm²时,随施氮量减少焦油释放量降低;烤烟中部叶焦油释放量与烟碱、总氮呈显著正相关,与纤维素、还原糖分别呈显著和极显著负相关;烟碱和总氮对焦油释放量有较大的直接作用和间接作用。综合研究表明,吉林延边地区可以通过适当的氮钾配施以及调控部分烟叶化学性状来达到降焦减害的目的。     

低钾胁迫对烟草幼苗碳氮代谢基因表达谱的影响

为探索烟草响应低钾胁迫的分子机制,对K326烟草幼苗进行了0、6、12和24 h的低钾胁迫处理,并利用定制的烟草全基因组芯片,分析了烟草幼苗基因表达谱的变化。结果表明,与0 h相比,6、12和24 h的3个时间点差异表达在2倍以上(p<0.05)的基因总数为3790个。从功能方面看,这些差异表达基因广泛参与了烟草的各种生物学过程,包括抗氧化活性、应激反应、运输活性、发育过程、催化活性、生物调节、代谢过程等。其中包括了硝酸还原酶基因NIA2等10个参与烟草氮代谢的基因,以及UGP等44个参与烟草碳水化合物与糖代谢的基因。本研究结果说明,低钾胁迫对烟草的基因表达产生了广泛的影响,进而可能影响到烟草的碳氮等基础代谢。     

Lactose Solubility and Crystal Growth as Affected by Mineral Impurities

Single crystal growth method was applied to determine lactose solubility, growth rate and morphology of lactose crystals grown in model lactose solutions containing various salts and in whey ultrafiltration (UF) permeate solutions. Salts either increased or decreased the lactose crystal growth rate, due to effects on lactose solubility. Addition of LiCl led to a maximum increase in growth rate and a maximum decrease in lactose solubility, while K₂HPO₄ had opposite effects. Growth rates of individual lactose crystals in whey UF permeate solutions were lower and lactose solubility higher than those in pure lactose solutions.     

Color Stability of Strawberry Jam as Affected by Cultivar and Storage Temperature

The stability of three strawberry cultivars was evaluated for changes in jam color quality during processing and storage at 20°, 30° and 37°C for 200 days. Anthocyanin content was determined by HPLC. The effect of cultivar, processing and storage on jam pigments, instrumental color (L*, a*, b*) and consumer preference were also determined. ‘Oso grande’ jam had the lowest anthocyanin concentration (110 mg/g f.w), higher monomeric pigment degradation during processing and storage, highest pH, least desirable color score from the sensory panel and shortest shelf-life. Similarities were found between jams prepared with ‘Chandler'and Tudla’ cultivars, as well as initial differences in total anthocyanin concentrations (195 and 130 mg/g f.w.).     

Quality of Shredded Carrots as Affected by Packaging Film and Storage Temperature

ABSTRACT: Different packaging films and storage temperatures were used to establish a range of equilibrium modified atmospheres for storage of shredded carrots. Quality and storage-life of the packaged shredded carrots were determined using sensory evaluation, microbial counts, and a range of physical tests. Minimal processing steps such as peeling and shredding caused physical damage, physiological stress, and enhanced microbial growth, leading to a reduced shelf life when compared to the whole vegetable. A P-plus microporous film (CO₂ permeability of 29 X 10³mL.m ^-2.d ^-1.atm ^-1) was the most suitable for the storage of shredded carrots. Findings indicated that deterioration in these products was triggered by the depletion of oxygen more than by the rise in carbon dioxide.     

氮源对2株海洋微藻生长及脂肪酸合成的影响

以三角褐指藻、扁藻为材料,研究了NaNO3、尿素和NH4Cl等不同氮源对其生长、叶绿素、可溶性糖、可溶性蛋白、干重、总脂及脂肪酸含量的影响。结果表明:以尿素为氮源时,三角褐指藻的生物量、生长速率、叶绿素、可溶性糖、可溶性蛋白的含量最高,NaNO3和NH4Cl次之;以NH4Cl为氮源时,细胞内的总脂含量最高,占干重的47.5℅。与三角褐指藻不同,以NH4Cl为氮源时,扁藻的生物量、生长速率、叶绿素、可溶性糖、可溶性蛋白的含量最高,尿素和NaNO3次之;当以NaNO3为氮源时,细胞内的总脂含量最高,占干重的38.5℅。     

Profiles of New Zealand Snapper (Pagrus auratus) Postmortem Metabolism as Affected by Acclimated Temperature and Postmortem Storage Temperature

ABSTRACT: Chemical anesthesia (AQUI-S^TM) was used to harvest tank-reared snapper ( Pagrus auratus ) from late summer (19.6 °C) and winter (11.9 °C) acclimated populations in a "rested" state. Carcasses were stored in seawater at temperatures between 2 and 20 °C to investigate the effects of acclimation and storage temperature on the postmortem metabolic rate. Contour plots of postmortem muscle pH [lactic acid] and adenosine triphosphate/inosine monophosphate measurements revealed critical temperature transitions: 16 to 18 °C (coinciding with seasonal behavioral changes) and 4 to 6 °C (consistent with cold injury). DC eye surface potential (ESP) was evaluated as a noninvasive indicator of tissue-temperature interactions and showed similar patterns of critical temperature transitions.     

High-pressure-cooked Low-fat Pork and Chicken Batters as Affected by Salt Levels and Cooking Temperature

The application of high pressure (200 and 400 MPa, 30 min) favored water and fat binding properties of chicken and pork batters even at low ionic strength. Textural properties of meat batters (particularly hardness and chewiness, and to a lesser extent springiness and cohesiveness) were influenced by cooking temperature. High pressures influenced the texture of batters, so that pressurized samples were less hard, cohesive, springy or chewy than nonpressurized samples; this effect was not related to on salt concentration. High pressure treatment limited the formation of gel structures, which probably was associated with its preserving effect against thermal denaturation of meat proteins.     

氮源对等鞭金藻生长和脂肪酸组成的影响

研究了在培养基中添加不同浓度的NaNO3、NH4 Cl、NH2 CONH2 对等鞭金藻生长和脂肪酸组成的影响。结果表明 ,当不在培养基中添加氮源时 ,等鞭金藻生长缓慢。但C16∶0 ,C18∶0 和多不饱和脂肪酸 (PUFAs)占总脂肪酸的比例最高。氮浓度在 0 9～ 7 0mmol/L之间 ,等鞭金藻的生长随着NH4 Cl浓度的增加而下降 ,随着NH2 CONH2 浓度的增加而升高 ,而受NaNO3浓度变化的影响不显著。以NaNO3或NH2 CONH2 为氮源 ,DHA占总脂肪酸的比例随着其浓度的增加先上升后下降 ,最适浓度为 3 5mmol/L。以NH4 Cl或NH2 CONH2 为氮源 ,PUFAs占总脂肪酸的比例随着氮浓度的增加而下降 ,且等鞭金藻DHA占干重的比例在 1 8mmol/L的浓度时达到最高 ,分别为1 8%和 1 6% ;以NO- 3为氮源 ,在浓度为 3 5mmol/L时DHA含量最高 ,为 2 2 %。在相同氮浓度下 ,DHA占干重的比例以NaNO3为氮源最高 ,以NH2 CONH2 为氮源时最低。     

氮气气调胁迫对赤拟谷盗生长发育及种群动态的影响研究

为明确不同氮气体积分数对赤拟谷盗生长发育和种群动态的影响,本文研究了在27~29 ℃、70~80% RH,氮气体积分数分别为78%（对照组）、90%、95%、98%下赤拟谷盗的发育历期、存活率、产卵量及其他生命表参数。研究结果表明,不同氮气体积分数对赤拟谷盗生长发育和繁殖具有显著影响。在78%、90%氮气体积分数下,增加氮气体积分数对赤拟谷盗卵、幼虫、蛹的发育有明显的抑制作用。赤拟谷盗每雌产卵量随着氮气体积分数的增加而显著减少;赤拟谷盗世代平均周期（T）、种群加倍时间（Dt）随着氮气体积分数的增加而增加。种群净增值率（R0）、种群趋势指数（I）、内禀增长率（rm）、周限增长率（λ）均随着氮气体积分数的增加而降低。当氮气体积分数为95%、98%时,赤拟谷盗不能完成世代发育。在相同氮气体积分数下赤拟谷盗各虫态间的发育历期差异显著。氮气气调处理对赤拟谷盗卵的孵化率、1~5龄幼虫及蛹的存活率均有显著的抑制作用,对赤拟谷盗6龄、7龄幼虫和预蛹的存活率无显著影响。     

Water Activity and Temperature Effects on Fungal Growth and Ochratoxin A Production by Ochratoxigenic Aspergillus carbonarius Isolated from Tunisian Grapes

ABSTRACT: This study investigated the effects of temperature (15 to 37 °C) and water activity (0.90 to 0.99) on the growth and production of ochratoxin A (OTA) by Aspergillus carbonarius cultured on synthetic nutrient medium (SNM) after 5 and 10 d of incubation. Total of 8 ochratoxigenic A. carbonarius, isolated from vineyards located in different regions of Tunisia, were used. Growth data were modeled by the flexible model of Baranyi and growth rates at each set of conditions were obtained. For both growth and OTA production, optimal water activity was 0.99; however, optimal temperature varied. The optimal temperature for growth was 30 °C. At 37 °C, the growth rate decreased significantly (P < 0.05). Maximum toxin production occurred at temperatures in the range of 15 to 25 °C with the optimum one depending on the isolate tested. Significant amounts of OTA were produced after only 5 d of incubation. Our results showed that A. carbonarius isolated from Tunisian grapes behave as those from European and Australian grapes, as reported in the literature, although some differences in trends for growth and OTA production were observed.     

低温对锈赤扁谷盗不同虫态及其种群的抑制作用

以常见的储粮害虫锈赤扁谷盗为研究对象,研究5、10、15、20℃低温对其不同虫态生长发育的影响,分析低温储粮下害虫对粮食的损害情况,观察低温对其种群增长的影响,为低温储粮状态下的害虫防控提供参考。结果表明,5～20℃低温处理30 d后,成虫死亡率均在30%以下;幼虫死亡率在5℃时最高为76.7%,在10、15、20℃下均低于30%。5、10、15、20℃下,幼虫的致死中时分别为21、44、38、49 d, 10～20℃的LT₅₀值为5℃的1.8～2.4倍;卵在5℃和10℃下不能孵化,15℃下无法完成发育历期,20℃下可发育为成虫。低温对害虫种群增长有显著抑制作用,随着温度降低,害虫对粮食的损害程度逐渐减弱,20℃下害虫对粮食损害程度最大。因此,5～20℃低温储粮可以抑制害虫种群的增长,但致死效果较差,仍需采取有效的害虫防控措施,以达到保质控害,保障粮食安全的目的。     

施氮量对翠碧1 号生长发育及烟叶质量风格的影响

通过田间试验和化学分析,研究了不同施氮水平对翠碧1 号烤烟生育期、烤后烟叶产质量和烟叶风格的影响。结果表明,不同施氮量对烤烟生育期、经济性状、外观质量、化学成分和感官评吸质量均有显著的影响。施氮量增加,烟株大田生育期明显延长;烤后烟叶产量、不同部位单叶重、总氮和烟碱含量明显增加,总糖和还原糖含量、还原糖/烟碱和总氮/烟碱比值表现下降的趋势;烟叶“清香型”风格彰显趋向弱化。施氮量大于78 kg/hm² 时,烤后烟叶产值增加不显著;施氮量在58.5～97.5 kg/hm² 时,烟叶内在化学成分较协调,外观质量和感官评吸质量较好,烟叶“清香型”风格彰显较明显。     

Atmospheric Composition and Quality of Fresh Mushrooms in Modified Atmosphere Packages As Affected by Storage Temperature Abuse

Mushrooms (Agaricus bisporus) were packaged in 4-liter modified atmosphere (MA) containers, and a steady-state atmosphere of 5% and 10% was maintained at 4 °C. Temperature was fluctuated from 4 °C to 20 °C during 12-d storage period in cycles: 2 d at 4 °C followed by 2 d at 20 °C. Temperature increase during fluctuations caused anoxic atmospheres both in O₂ (1.5%) and CO₂ (22% to 10%). The quality of mushrooms stored under temperature fluctuating regime was severely affected as indicated by extensive browning, loss of firmness, and the level of ethanol in the tissue compared to mushrooms stored at constant temperature. It was clear that temperature fluctuation, even if it should occur once, can seriously compromise the benefits of MA packaging and safety of the packaged produce.     

Germination, Growth, and Toxin Production of Nonproteolytic Clostridium botulinum as Affected by Multiple Barriers

ABSTRACT The effect of combinations of pH (6.5, 5.75), NaCl (0.25,1.75%), and incubation temperatures (7,13 °C) on spore germination, outgrowth, and time to toxicity of nonproteolytic Clostridium botulinum was examined in a broth system. Spores of four toxin type E and nonproteolytic type B were inoculated (10⁴/ml) into Tryptone Peptone Glucose Yeast Extract (TPGY) broth. Cultures were monitored for three weeks, or until toxin was detected. A modified FSIS‐amplified ELISA (comparable in sensitivity to the mouse bioassay) was used to screen cultures for neurotoxin. Combinations of the most inhibitory level for each barrier reduced the degree and rate of germination, the lag and growth rate of vegetative cells, and the time to toxicity.     

覆盖对烟田土壤水热状况和烤烟生长及品质的影响

为探讨覆盖对丽江金沙江河谷地区烟田土壤温度、水分及烤烟生长和化学成分的影响,以云烟87 为材料,于团棵期后,进行揭膜及不同覆盖的比较试验。结果表明,覆盖能提高烟株农艺性状,促进烟株生长;能调节土壤温度,减小土壤温差,使土壤含水量提高;覆盖使叶绿素相对含量提高,降低总糖、还原糖含量,提高总氮、烟碱、蛋白质含量。其中地膜加秸秆覆盖可以降低膜内土壤温度,克服单一地膜覆盖温度过高而秸秆覆盖地温较低的弊端,有利于改善根区土壤环境,维持和提高根系活力,提高烟叶品质。     

氮气及温、湿度条件对锈赤扁谷盗卵发育的影响

在3种氮气浓度（78.8%,83.0%,88.0%）、3种相对湿度（69.6% RH,75.1%RH,83.7%RH）及5种温度（19.9、25.0、29.3、34.7、39.8 ℃）组合条件下,研究了锈赤扁谷盗卵的孵化情况。结果表明：发育历期为2.2～18.9 d,发育起点温度为13.8～14.3 ℃,最高临界发育温度为40.4～43.0 ℃,有效积温为61.6～115.6 日度。发育历期、发育速率与温度之间分别是“指数”型及“S”型曲线关系。氮气及温、湿度因素相互作用影响了卵的孵化,88.0%的氮气对孵化有显著的抑制效应,温度（> 30.0 ℃）及湿度（> 69.6% RH）强化了氮气对孵化的抑制效应。     

Volatile Profiles of Raw and Cooked Turkey Thigh as Affected by Purge Temperature and Holding Time Before Purge

Effects of purge temperature and sample holding time on volatile profiles were determined using a purge-and-trap/gas chromatography unit with autosampler. Purge temperature and sample holding time before purge influenced the profile of volatiles in raw and cooked meat. The most notable changes were observed when the purge temperature was increased from 60°C to 80°C. Many of the changes in volatiles were related to oxidation of lipids. We recommend that meat should be purged at 40°C or 50°C (temperature at sensory analysis) to minimize heat-induced production of volatiles and sample purge should be done within 3h after sampling to reduce oxidative changes during sample holding time.