氯苯胺灵对马铃薯品质的影响

以"荷兰十五"马铃薯块茎为试材,分别采用质量浓度为0、0.1、0.3、0.5 g/kg的氯苯胺灵溶液进行喷施处理后,以喷涂0 g/kg氯苯胺灵为对照,置于0、8℃下贮藏,定期测定马铃薯呼吸强度、腐烂率、发芽率、可溶性固形物、还原糖含量和Vc含量等品质指标,以研究贮藏温度和氯苯胺灵浓度对马铃薯发芽、腐烂和贮藏品质的影响。结果表明,0℃条件下,CIPC用量为0.3 g/kg时,贮藏结束后对马铃薯的呼吸作用抑制效果最显著,降低了66.1%,同时,与对照组相比发芽率降低6.7%,营养成分中的可溶性固形物增加31.0%,还原糖含量降低18.8%,Vc含量比对照高15.5%,良好地保持了马铃薯的贮藏品质,减少了营养成分的损失。     

不同烹调方式对马铃薯中氯苯胺灵残留量的影响

抑芽剂主效成分氯苯胺灵（CIPC）在马铃薯中的残留量不但受施用方式的影响,而且也受马铃薯烹调方式的影响。用自主研发的抑芽剂粉剂处理马铃薯4d,然后分别在常温（18～22℃）和低温（3～5℃）条件下贮藏30d。结果表明,采用普通锅、高压锅和微波炉三种烹调方法处理的马铃薯,薯皮中CIPC的含量分别为22.48～36.27、45.35～56.40、63.72～74.61mg/kg;薯肉中CIPC的含量分别为2.17～3.32、2.86～3.70、3.54～4.02mg/kg。三种处理方法与对照相比,薯皮中CIPC含量差异显著,薯肉中CIPC含量差异不显著。其中在低温条件下贮藏的马铃薯中CIPC残留量最高,而且在煮过马铃薯的水中也发现了少量CIPC。     

1-甲基环丙烯处理对窖藏马铃薯的保鲜效果

以黑龙江省绥化市品种为黄麻子的马铃薯为试材,采用不同浓度1-甲基环丙烯(1-MCP)处理,研究窖藏马铃薯采后生理、贮藏品质及发芽率。结果表明:1.0μL/L 1-MCP处理,能有效减缓块茎淀粉的降解、抑制VC和总酚含量的下降及还原糖的上升,能显著降低块茎的呼吸速率,抑制与块茎衰老相关的PPO和POD活性的快速升高。在此处理方式下,贮藏到180d,块茎并未发芽,保鲜效果良好。     

微波处理对‘新大坪’马铃薯贮藏品质的影响

为了提升马铃薯贮藏品质,分别使用不同功率微波对马铃薯块茎进行处理,并将处理后的马铃薯保存在4℃的冰箱里,贮藏期间每10 d测量马铃薯的失重率、Vc含量、可溶性固形物含量、淀粉含量、褐变指数、多酚氧化酶活性、过氧化物酶活性。结果表明,微波处理能够有效提升马铃薯的贮藏品质,但微波处理不足(115 W/1 min)对马铃薯贮藏品质的提升效果不明显,微波处理过量(220 W/3 min)则会对马铃薯生理和品质造成损伤。实验中以微波功率220 W处理2 min的保鲜效果最佳,能够有效避免马铃薯块茎质量及Vc的损失,保持可溶性固形物含量和淀粉含量,减缓褐变指数的升高,抑制多酚氧化酶和过氧化物酶活性。该研究为马铃薯提供了微波处理提升贮藏品质的方法。     

马铃薯抑芽可湿性粉剂研发及抑芽效果研究

为研制出价廉高效的以氯苯胺灵[isopropyl N-(3-chlorophenyl)carbamate,CIPC]为抑芽成分的马铃薯抑芽可湿性粉剂,在制得以硅藻土为载体的母粉基础上,通过对多种分散剂和润湿剂的筛选,得到产品最佳配方:CIPC 2.5%、硅藻土79.5%、净洗剂LS 6%、羧甲基纤维素钠(carboxymethylcellulose sodium,CMC-Na)3%、二异丁基萘磺酸钠2%和十二烷基硫酸钠(sodium dodecyl sulfate,SDS)7%。并比较该抑芽可湿性粉剂的4个不同使用剂量对马铃薯块茎的贮藏效果,发现800 mg/kg的使用剂量抑芽效果最佳,8℃～12℃贮藏5个月,抑芽率为85.61%。     

不同愈伤时间对常温贮藏期间马铃薯干腐病和品质的影响

研究了不同愈伤处理时间对常温贮藏条件下马铃薯块茎干腐病发病率和病情指数、发芽率和芽长、失重率及绿化率的影响.结果表明,愈伤处理能够降低马铃薯块茎损伤接种硫色镰刀菌(Fusarium sulphureum)的干腐病发病率和病情指数,愈伤时间越长效果越好.愈伤降低了损伤和无损伤处理块茎的发芽率,但促进了发芽块茎芽的生长.损伤块茎的失重率在较长时间的愈伤后明显降低,但愈伤对块茎绿化没有显著影响.由此表明,愈伤能够促进周皮的形成,提高块茎抗性,从而有效抑制干腐病的发生,延缓块茎的发芽和失重.     

低氧高二氧化碳贮藏环境对马铃薯品质的影响

为探索低氧高二氧化碳贮藏环境对马铃薯贮藏品质的影响,本实验研究了5%(体积分数,下同)O_2+2%CO_2、5%O_2+4%CO_2、5%O_2+6%CO_2、5%O_2+8%CO_2及5%O_2+10%CO_2的气体环境对马铃薯在4℃和10℃贮藏120 d期间主要营养品质、外观品质及生理品质的影响。结果表明:5%O_2+2%CO_2的贮藏环境可延缓贮藏过程中还原糖含量的上升,并且保持良好的薯皮色度及抑制膜脂过氧化反应,保护膜系统的相对完整性,延缓多酚氧化酶活力的升高,从而延缓马铃薯块茎的衰老;而5%O_2+10%CO_2的贮藏环境反而会引起还原糖的大量积累,但可明显抑制块茎的发芽。本研究结果可为加工型马铃薯的贮藏提供理论依据。     

不同处理对马铃薯货架期内保鲜效果的影响

为探究不同处理方式对马铃薯的货架保鲜效果,以市售马铃薯为原料,将乙醇熏蒸、海藻酸钠涂膜及壳聚糖涂膜处理后的马铃薯置于600 lux、25℃的人工气候箱中模拟货架期条件储藏,对贮藏期间马铃薯的失重率、发芽指数、色泽、叶绿素含量、硬度等品质指标及龙葵素含量进行测定分析,结合主成分分析综合评价马铃薯在不同处理下的保鲜效果。结果表明：经过9d的贮藏,与对照组相比,3种处理均有效延缓了马铃薯的绿变及萌芽的产生;海藻酸钠涂膜及壳聚糖涂膜处理均可显著抑制马铃薯贮藏期间的表观色泽变化、失重率、硬度的下降及块茎和皮层中龙葵素的合成;乙醇熏蒸处理加剧了马铃薯贮藏期间的失重率及硬度下降;对马铃薯货架期的保鲜效果中以海藻酸钠涂膜处理最具有优越性,壳聚糖涂膜处理次之,乙醇熏蒸处理的保鲜效果相对较差。该研究可为马铃薯的产后贮藏保鲜提供理论参考。     

UV-C处理抑制马铃薯贮藏期发芽及相关机理研究

为提高马铃薯的食用安全性和贮藏品质,本实验研究了短波紫外线(ultraviolet C,UV-C)处理对马铃薯贮藏过程中发芽品质的影响。采用10 kJ/m2 UV-C对马铃薯进行一次处理(贮藏前),二次处理(贮藏前及中期),并测定发芽率、还原糖、苯丙氨酸解氨酶、多酚、赤霉素、α-茄碱等指标。结果表明,UV-C处理能够有效抑制马铃薯贮藏过程中的发芽,同时延缓赤霉素和α-茄碱的上升。二次处理组贮藏至90 d时,薯皮和肉质部分的α-茄碱含量仅为对照组的71.09%、65.75%;105 d时发芽率为68.78%,还原糖含量为0.40%,失重率为4.71%,贮藏品质均优于对照组和一次处理组。综上所述,当处理剂量和方式适宜时,UV-C可在马铃薯发芽控制及品质保持方面获得良好效果,其中二次处理更具优势。     

不同浓度CO2对贮藏期间马铃薯生理品质的影响

以克新6号马铃薯为试材,将愈伤后的马铃薯放入自制的气调箱,设定不同的CO2浓度,研究贮藏在9~11℃,湿度85%~95%条件下不同浓度CO2对马铃薯生理品质的影响。结果表明,适当的CO2浓度(1.00%)能有效减缓块茎淀粉的降解,抑制总酚含量的下降,保持贮藏期间较低的还原糖水平和较高的POD活性,抑制PPO酶活性。CO2浓度过高(1.5%CO2、2.0%),不利于块茎淀粉积累,使还原糖含量的增加,总酚含量降低,POD活性升高,在贮藏120d时部分块茎开始发芽。由此表明,CO2浓度为1%可延长块茎的休眠,利于马铃薯的贮藏,通过控制CO2浓度可以延长马铃薯的保鲜期。     

褪黑素对小鼠抗氧化作用的影响

目的:研究小鼠在受到脂多糖(LPS)刺激时,褪黑素的抗氧化作用,并探讨其可能机制。方法:用脂多糖建立氧化应激模型,检测血清、小肠、肝脏和脾组织中的ROS含量,肝脏、脾组织中的谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)、丙二醛(MDA)的变化。结果:在LPS刺激后的4h和16h,褪黑素均能降低血清、小肠、肝脏、脾组织中的ROS含量,提升肝脏和脾组织中的GSH-PX、SOD活性,降低MDA含量。结论:褪黑素有助于增强氧化应激小鼠的抗氧化能力,降低组织中NO含量与NO合成酶活性,增加了SOD、GSH-PX等抗氧化酶的活性,保护机体免受氧化损伤。     

Determination of the variability of both hydrophilic and lipophilic toxins in endemic wild bivalves and carnivorous gastropods from the Southern part of Chile

The aim of this study was to analyse and determine the composition of paralytic shellfish poisoning (PSP) toxins and lipophilic toxins in the Region of Aysén, Chile, in wild endemic mussels (Mytilus chilensis, Venus antiqua, Aulacomya ater, Choromytilus chorus, Tagelus dombeii and Gari solida) and in two endemic carnivorous molluscs species (Concholepas concholepas and Argobuccinum ranelliforme). PSP-toxin contents were determined by using HPLC with fluorescence detection, while lipophilic toxins were determined by using LC-MS/MS. Mean concentrations for the total of PSP toxins were in the range 55–2505 μg saxitoxin-equivalent/100 g. The two most contaminated samples for PSP toxicity were bivalve Gari solida and carnivorous Argobuccinum ranelliforme with 2505 ± 101 and 1850 ± 137 μg saxitoxin-equivalent/100 g, respectively (p < 0.05). The lipophilic toxins identified were okadaic acid, dinophysistoxin-1 (DTX-1), azaspiracid-1 (AZA-1), pectenotoxin-2 (PTX-2) and yessotoxins (YTX). All analysed molluscs contained lipophilic toxins at levels ranging from 56 ± 4.8 to 156.1 ± 8.2 μg of okadaic acid-equivalent/kg shellfish together with YTX at levels ranging from 1.0 ± 0.1 to 18 ± 0.9 μg of YTX-equivalent/kg shellfish and AZA at levels ranging from 3.6 ± 0.2 to 31 ± 2.1 μg of AZA-equivalent/kg shellfish. Furthermore, different bivalves and gastropods differ in their capacity of retention of lipophilic toxins, as shown by the determination of their respective lipophilic toxins levels. In all the evaluated species, the presence of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods was not identified, in contrast to the identification of PSP toxins, where the profiles identified in the different species are directly related to biotransformation processes. Thus, this study provides evidence that the concentration of toxins in the food intake of the evaluated species (Bivalvia and Gastropoda class) determines the degree of bioaccumulation and biotransformation they will thereafter exhibit.     

高效液相色谱法同时检测6种甜味剂

建立同时测定6种人工合成甜味剂阿斯巴甜、糖精钠、甜蜜素、安塞蜜、纽甜、甜聚糖甙的高效液相色谱分析方法。以Platicil ODS柱为分离柱,20mmol/L硫酸铵缓冲溶液(pH4.4)-乙腈为流动相,进行梯度洗脱。采用二极管阵列检测器进行检测,整个分离过程在30min内完成。6种甜味剂在0.4～120mg/L范围内其质量浓度与峰面积的线性关系良好,相关系数为0.99967～0.99998,在4.0～10.0mg/kg范围内,样品加标回收率为85%～107%;相对标准偏差小于3.2%。该方法简便、快速,净化效果较好,可用于食品中6种甜味剂的同时测定。     

气相色谱法检测饮料中二羰基化合物

建立同时在线检测丙酮醛和乙二醛的气相色谱方法。确定检测二羰基化合物的最佳条件为：以丁二酮为内标,以邻苯二胺为衍生化试剂,邻苯二胺的用量67 倍于二羰基化合物、衍生化时间10 min、萃取溶剂二氯甲烷、超声时间15 min、萃取2 次、柱箱初始温度40 ℃、程序升温5 ℃/min,色谱柱载气流量2.0 mL/min,分流比1∶1。丙酮醛和乙二醛的定量限（RSN≈10）分别为0.06 mg/L和0.08 mg/L,检出限（RSN≈ 3）分别为0.02 mg/L和0.03 mg/L,方法灵敏度高。     

对药剂敏感性不同的烟蚜体内几种关键性酶活性的比较分析

对吡虫啉和氧化乐果在三明地区和合肥地区烟蚜的毒力进行了测定,并对两地烟蚜的羧酸酯酶、乙酰胆碱酯酶和谷胱甘肽转移酶的活性进行了研究.结果表明吡虫啉对两地烟蚜的生物活性远高于氧化乐果,三明烟蚜对两种药剂的敏感性都比合肥烟蚜的低,三明烟蚜种群的毒力方程b值低,存在一定的异质性;两地烟蚜的羧酸酯酶、乙酰胆碱酯酶活性差异不显著,但三明地区烟蚜的谷胱甘肽转移酶活性显著高于合肥地区烟蚜.     

盐胁迫对芦荟几项生理生化指标的影响

以常规库拉索芦荟为对照 ,检测经不同浓度海水灌溉 3a的库拉索芦荟的几项生理生化指标的变化。结果表明 ,盐胁迫对芦荟全叶原汁的吸光度、pH值、相对密度、总固形物、水分含量和镁离子含量的影响较小 ,但对多糖和钙离子含量的影响较大。 2 5 %或 5 0 %海水灌溉的芦荟中多糖含量很高 ,增加了 2～ 3倍 ;低浓度海水灌溉下 ,芦荟中钙离子含量高于对照 (CK) ;而在高浓度海水灌溉下 ,芦荟中钙离子含量则低于CK。在盐胁迫下 ,芦荟体内积累一定量丙二醛 ,而脯氨酸含量则下降 ;过氧化物酶活力先在低盐条件下显著提高 ,随后则下降 ,与CK相当 ;过氧化氢酶活力随海水浓度的提高而迅速下降 ;超氧物歧化酶活力受盐浓度影响不大 ,基本上趋于稳定。     

Correlation of methylglyoxal with acrylamide formation in fructose/asparagine Maillard reaction model system

α-Dicarbonyl compounds were highly reactive intermediates formed in Maillard reaction (MR), and o-phenylenediamine (OPD) was widely used as a trapping agent for α-dicarbonyl compounds. Both aqueous fructose/asparagine (Fru/Asn) and fructose/asparagine/o-phenylenediamine (Fru/Asn/OPD) model systems were heated at 150 °C for up to 30 min. Methylglyoxal (MG) was the main α-dicarbonyl compounds formed in MR, which was chosen as a representative of α-dicarbonyl compound to investigate the influence on acrylamide (AA) formation. The concentrations of AA, MG and Asn were detected during MR by HPLC method. The results indicated that the formation of AA increased with the heating time, and nearly 75% of AA was formed through the participation of α-dicarbonyl compounds. The amounts of formation and consumption of MG increased with heating time, and from 12 min of reaction, the consumed amounts of MG accounted for 62.1–90.3% on the basis of total amounts of MG formed in MR, suggesting that most of the MG took part in further reactions. Meanwhile, Asn concentration decreased with heating time in both models. The formation of AA and consumption of Asn were highly correlated with MG. Indeed, as MG concentration in MG/Asn model system decreased during heating at 150 °C, the concentration of AA significantly increased. The coefficient of correlation between consumed amounts of MG and the formed amounts of AA was 0.931, demonstrating that MG plays a role in AA formation.     

Use of poly(ether-block-amide) in pervaporation coupling with a fermentor to enhance butanol production in the cultivation of Clostridium acetobutylicum

The toxicity of the end-products of acetone-butanol-ethanol (ABE) process, mainly butanol, is recognized as the major problem contributing to the low productivity of butanol. The pervaporation technique was regarded as one of the ways to efficiently remove organic components. The results of pervaporation performance of poly(ether-block-amide) (PEBA) and polydimethylsiloxane (PDMS) membrane in a model solution indicated that PEBA membrane owned a higher butanol permeation flux of 9.975 gm(-2)h(-1) as opposed to 3.911 gm(-2)h(-1) using a PDMS membrane. Moreover, a higher temperature would result in a higher permeation flux, but has a lower separation factor (α) obtained, while using PEBA membrane. The batch fermentor operation connected to the pervaporation with PEBA membrane created 43% and 34% of increase in the butanol productivity and in the yield as compared to that of the simple batch. The fed-batch fermentation mode by glucose feeding combined with PEBA pervaporation lasting for 24h could achieve 39% increase of butanol productivity as compared to a simple batch. Conclusively, the pervaporation with PEBA membrane coupling with fermentor was presumed to be capable of enhancing butanol production in ABE fermentation, which might have the potential applied in the commercialized ABE fermentation process.     

嘧菌酯处理对厚皮甜瓜POD和CAT活性的影响

以厚皮甜瓜(Cucumis melonL.)作为实验材料,研究嘧菌酯处理对厚皮甜瓜采后过氧化物酶和过氧化氢酶活性的影响,实验结果表明:甜瓜经50、100、200mg/L嘧菌酯浸泡处理后,其果实的过氧化物酶和过氧化氢酶活性均有所变动,其中,100mg/L嘧菌酯处理,两种酶的活性均处于稳定上升趋势,到第14天达到最高值,此后呈下降趋势,但到第21天时,酶活性仍高于对照。     

亚甲基蓝对单增李斯特菌菌膜的光动力杀伤作用

探讨单增李斯特菌（Listeria monocytogenes,LM）生物菌膜的生长特性及亚甲基蓝对LM生物菌膜光动力杀伤作用。通过结晶紫染色法判断与观察LM生物菌膜的形成并用酶标仪在595 nm波长处对其不同生长阶段的生物量进行测定,同时通过细菌平板菌落计数法研究亚甲基蓝对LM生物菌膜的光动力杀伤作用。结果表明：结晶紫染色法可用于定性判断与观察LM生物菌膜,且随着培养时间的延长,LM生物菌膜生物量不断增加,形成的网状结构越来越致密。当光敏剂质量浓度为10 μg/mL的亚甲基蓝在光功密度为200 mW/cm2 的可见光照射30 min时,即可使LM生物菌膜的失活率达到99.99%以上,其菌落数降低了4.08（lg（CFU/mL））。亚甲基蓝对LM生物菌膜的光动力灭活作用非常显著,其杀伤效果主要取决于光敏剂质量浓度和光照时间。