山东省玉米真菌毒素污染状况调查及分析

为掌握山东省玉米的真菌毒素污染状况,评估污染带来的安全风险,为加强真菌毒素污染防控提供依据,采集了山东省玉米主产县2013年~2014年收获和储藏的玉米样品共520批次,采用液相色谱—飞行时间质谱联用仪(UPLC-Q-TOF)方法检测了玉米中黄曲霉毒素(AFB_1、AFB_2、AFG_1、AFG_2)、伏马毒素(FB_1、FB_2、FB_3)、呕吐毒素(DON)和玉米赤霉烯酮(ZEN)的污染水平。结果表明,AFB1、AFB2、AFG1在玉米中检出率分别为18.08%、7.88%、0.77%,平均含量分别为7.62、0.60、0.05μg/kg;FB1、FB2、FB3检出率分别为92.50%、88.08%、83.85%,平均含量分别为1 798.69、531.83、197.71μg/kg;DON检出率为26.35%,平均含量为240.44μg/kg;ZEN检出率为14.62%,平均含量为74.90μg/kg;AFG2未检出。调查结果还表明,伏马毒素在所测样品中污染最为严重,超标率达33.46%;单一样品受多种毒素混合污染的情况较严重。     

8种抗寒平欧杂交榛子油脂成分分析及比较

比较8种平欧榛子的差异性,利用索氏提取法测定油脂含量,气相色谱法和比色法进行油脂脂肪酸组成和α-VE含量分析,聚类分析用于区分其类别。结果表明:8种平欧榛子有显著差异,含油量平均为56.36%,范围为52.92%~59.24%;单不饱和脂肪酸、多不饱和脂肪酸、饱和脂肪酸的平均相对含量分别为72.54%、16.11%、7.85%;最丰富的脂肪酸是油酸,平均相对含量为72.29%,亚油酸与油酸总含量超过85%;α-VE含量为113.42~285.16μg/g。用3个主成分PC1(43.384%)、PC2(34.436%)、PC3(12.606%)作为合成变量通过聚类分析可得到4个类群:4#、5#、6#、7#为一类,8#为一类,2#、3#为一类,1#为一类。     

HPLC法测定玉米芯酸水解液中糖组分的含量

建立高效液相色谱法测定玉米芯酸水解液中糖组分。采用AminexHPX-87H柱(300mm×7.8mm),以0.01mol/L硫酸为流动相,流速为1.0mL/min,柱温:60℃,检测器为示差检测器;进样量20uL。结果表明:以峰面积定量,葡萄糖的线性范围为10⁵0ug(r=0.9999);平均回收率99.6%、RSD=0.73%(n=9)。木糖的线性范围为2050ug(r=0.9999);平均回收率99.6%、RSD=0.73%(n=9)。木糖的线性范围为20¹00ug(r=0.9999);平均回收率99.8%、RSD=0.45%(n=9)。、阿拉伯糖的线性范围为10100ug(r=0.9999);平均回收率99.8%、RSD=0.45%(n=9)。、阿拉伯糖的线性范围为10⁵0ug(r=0.9997);平均回收率100.2%、RSD=0.88%(n=9)。该方法简便、结果准确可靠,可用玉米芯酸水解液中糖组分的测定。     

激光复合诱变选育木薯原料柠檬酸高产菌

以柠檬酸生产菌黑曲霉 (Aspergillusniger) Wm -0 1为出发菌株 ,通过60 Co γ射线、硫酸二乙脂 (DES)及激光的复合诱变 ,采用高酸、高渗培养基筛选 ,从 2 46株突变株中筛选出一株木薯粉柠檬酸发酵高产菌株Wm 1 0 16,其发酵温度为 (3 9± 1)℃ ,周期 72h ,2 2 %木薯粉摇瓶 (平均总糖 17 9% ) ,产酸平均达 17 2 % ,15 0m3 大罐实验产酸 16 13 5 % ,周期 67h。     

采收期对“鄂选2号”山桐子果实成分及脂肪酸组成变化影响

为探寻木本油料山桐子果实及种子中油脂的积累动态规律,对不同采收期的预选品种“鄂选2号”的山桐子果实的整果、果肉和种子中的基本化学成分含量进行比较,并运用气相色谱-质谱联用对不同部位的油脂中的脂肪酸组成进行测定。结果表明,“鄂选2号”山桐子油料最佳采收期为盛花期后128 d左右,此时山桐子全果平均含油率为40.25%,果肉中的平均含油率为44.60%,种子中的平均含油率为30.55%。果实各部位的主要脂肪酸组成主要为肉豆蔻酸(C14∶0)、棕榈酸(C16∶0)、棕榈油酸(C16∶1)、珍珠酸(C17:0)、硬脂酸(C18∶0)、油酸(C18∶1)、亚油酸(C18∶2)、γ亚麻酸(C18∶3n6)、花生酸(C20∶0)、山嵛酸(C22∶0),其中种子油脂中亚油酸质量分数高于整果和果实,高达61.43%。     

山葡萄新品种"左优红"成苗特性

“左优红”硬枝扦插(自根)生根率平均为90.1%,成苗率87.1%。“左优红”与“贝达”条和苗木硬枝嫁接生根率平均为95.4%。催根幼苗根系多,移栽苗圃地成活率高,出圃成苗率94.3%。“左优红”与“公酿1号”和“双红”条和苗木硬枝嫁接生根率平均52.3%,成苗率平均仅为46.7%,分别低于“左优红”硬枝扦插(自根)和与“贝达”条和苗木嫁接40.4%和47.6%。“双红”、“公酿1号”条和苗木不宜做“左优红”硬枝嫁接的砧木。     

稻谷热风-真空联合干燥工艺参数优化

为了提高稻谷机械干燥效率和干后品质,降低干燥能耗,以平均干燥速率r、爆腰率b和单位能耗e为指标,以热风温度(X_1)、热风风速(X_2)、转换点含水率(X_3)、真空温度(X_4)为试验因素,设计Box-Behnken Design(BBD)试验对稻谷热风-真空联合干燥工艺参数进行优化,并将优化结果与热风、真空单一干燥方式最优工艺参数对应的指标值相比较。结果表明,联合干燥的最优工艺参数为:X_1=40℃、X_2=0. 7 m/s、X_3=20. 7%、X_4=38. 1℃,对应的平均干燥速率为0. 000 483 g/(g·min)、爆腰率为6. 3%、单位能耗为2 612 kJ/kg。联合干燥的平均干燥速率比热风干燥降低了29. 5%,比真空干燥提高了33. 1%;爆腰率比热风干燥降低了10%,比真空干燥降低了13. 7%;单位能耗比热风干燥降低了60. 1%,比真空干燥降低了12. 6%,说明稻谷热风-真空联合干燥与单一干燥方式相比优势明显。     

发酵佛手瓜渣产膳食纤维的工艺研究

佛手瓜属于高产低值作物,需要通过深加工来提高其附加值.以佛手瓜榨汁后的残渣为原料,用保加利亚乳杆菌和嗜热链球菌为菌种,混合发酵生产膳食纤维.经过单因素实验,选定接种量(X1=9%)、时间(X2=22h)和温度(X3=39℃)为中心点,以X1(8%,10%)、X2(21h,23h)、X3(38℃、40℃)为空间,以产量为响应值,进行Box-Behnken中心组合实验,最终确定生产的最佳工艺条件为接种量9%、发酵时间21.89h、发酵温度38.99℃.经验证实验确证,在最优条件下膳食纤维产率为1.50g/100g(原料).所得产品膳食纤维含量为99.32%,其平均持水性为6.34g/g,平均溶胀性为7.73mL/g.     

不同品种早稻糙米养分利用率的研究

以艾维菌成年公鸡为试验对象 ,采用真代谢能 (TME)法研究湖北省 8种早稻糙米营养物质的利用率及代谢能值并与玉米比较。结果表明 ,8种早稻糙米的物质、粗脂肪和总能的表现利用率和真利用率平均分别为 83.15 %和 85 .93%、94 .6 7%和 95 .0 3%、93.37%和 95 .71% ,高于玉米 (P <0 .0 1) ,粗蛋白的表观利用率和真利用率平均分别为 4 8.37%和 5 2 .92 % ,显著高于玉米 (P <0 .0 5 )。苏氨酸、缬氨酸、异亮氨酸、亮氨酸、苯丙氨酸、赖氨酸和精氨酸的表观利用率和真利用率平均为 79.32 %和 79.4 9%、83.5 4%和 83.6 8%、81.13%和 81.30 %、83.5 1%和 83.6 3%、82 .0 2 %和 82 .19%、82 .4 8%和 82 .6 2 %、90 .88%和 90 .92 % ,高于玉米 (P <0 .0 1) ,胱氨酸和蛋氨酸的表观利用率和真利用率平均分别为 80 .16 %和 80 .6 5 %、72 .76 %和 72 .91% ,显著高于玉米 (P <0 .0 5 )。表观代谢能和真代谢能值均高于玉米 ,分别为 16 .38MJ kg和 16 .6 8MJ kg。其中表观代谢能与玉米间差异极显著 (P <0 .0 1) ;除鄂早 6号 (P >0 .0 5 ) ,真代谢能与玉米间差异显著 (P <0 .0 5 )。糙米的营养价值相当于或高于玉米 ,是一种良好的能量饲料。     

HPLC测定参苓白术丸中人参皂苷的含量

目的建立高效液相色谱(HPLC)测定参苓白术丸中人参皂苷含量的方法。方法采用Thermo ODS C_(18)色谱柱,以乙腈为流动相A,以水为流动相B,梯度洗脱,流速为1.0 ml/min,检测波长为203 nm。结果人参皂苷Rg_1在0.0402～0.804 mg/ml范围内线性关系良好,r=0.9995(RSD=1.6%,n=5),平均回收率为94.2%(RSD=1.0%,n=5);人参皂苷Re在0.04038～0.8076 mg/ml范围内线性关系良好,r=0.9997(RSD=1.3%,n=5),平均回收率为92.6%(RSD=1.5%,n=6);人参皂苷Rb_1在0.04072～0.8144 mg/ml范围内线性关系良好,r=0.9999(RSD=1.4%,n=5),平均回收率为97.2%(RSD=1.3%,n=6)。结论方法专属性好、准确、灵敏,可用于参苓白术丸中人参成分的定量检测。     

Determination of ethanol,volatile fatty acids,lactic and succinic acids in fermentation liquids by gas chromatography

A rapid and simple quantitative method was developed to determine, by gas chromatography, the concentrations in fermentation liquids of ethanol, the C₂-C₆ volatile fatty acids, and lactic and succinic acids. Aqueous samples were acidified with 250μlml^?1 metaphosphoric acid (5:1 ratio), centrifuged, and injected directly on to a column containing a porous aromatic polymer (Chromosorb 101) maintained at 200°C in a gas chromatograph fitted with a flame ionisation detector. It was unnecessary to purify samples further before injection, although distillation and ion-exchange methods were examined. Derivatisation of lactic and succinic acids before injection was not necessary, but the lowest level of detection of these two relatively non-volatile acids was about four times greater than that for the volatile fatty acids. The method described was suitable for the analysis of rumen fluid, methane digester fluid, silage extracts and other anaerobic fermentation fluids. The relative retention times are given for 23 organic acids and six other fermentation end-products.     

Effects of abomasal infusions of fatty acids and 1-carbon donors on apparent fatty acid digestibility and incorporation into milk fat in cows

Our primary objective was to determine the effects of the abomasal infusion of 16-carbon (16C) and 22-carbon (22C) fatty acids (FA) on apparent FA digestibility, plasma FA concentrations, and their incorporation into milk fat in cows. Our secondary objective was to study the effects of 1-carbon donors choline and l-serine on these variables. Five rumen-cannulated Holstein cows (214 ± 4.9 d in milk; 3.2 ± 1.1 parity) were enrolled in a 5 × 5 Latin square experiment with experimental periods lasting 6 d. Abomasal infusates consisted of (1) palmitic acid (PA; 98% 16:0 of total fat), (2) PA + choline chloride (PA+CC; 50 g/d of choline chloride), (3) PA + l-serine (PA+S; 170 g/d of l-serine), (4) behenic acid (BA; 92% 22:0 of total fat), and (5) docosahexaenoic acid algal oil (DHA; 47.5% DHA of total fat). Emulsions were formulated to provide 301 g/d of total FA and were balanced to provide a minimum of 40 and 19 g/d of 16:0 and glycerol, respectively, to match the content found in the infused algal oil. Apparent digestibility of FA was highest in DHA, intermediate in PA, and lowest in BA. Digestibility of 16C FA was lowest in BA and highest in PA. The digestibility of 22C FA was highest in DHA relative to BA (99 vs. 58%), whereas 1-carbon donors had no effect on 22C FA digestibility. Plasma 16C FA concentrations were greatest with PA treatment, and 22C FA concentrations were ~3-fold greater in DHA-treated cows relative to all other treatments. Milk fat 16:0 content was highest in PA relative to BA and DHA (e.g., 37 vs. 27% in PA and DHA), whereas the milk yield of 16:0 was higher in PA relative to DHA (i.e., 454 vs. 235 g/d). Similarly, milk 22:0 content and yield were ~10-fold higher in BA relative to all other treatments, whereas DHA treatment resulted in higher content and yield of 22:6 in milk fat relative to all other treatments (41- and 38-fold higher, respectively). Consequently, the content of FA >16C (i.e., preformed) was higher in milk fat from cows infused with BA and DHA relative to PA. De novo FA content in milk did not differ between PA, PA+CC, and PA+S (~16% of milk fat) but was higher in BA and DHA treatments (19 and 21%, respectively). We conclude that FA carbon chain length and degree of saturation affected FA digestibility and availability for absorption as well as their incorporation into milk fat. The abomasal infusion of choline chloride and l-serine did not modify these variables relative to infusing palmitic acid alone.     

Short communication: Eicosatrienoic acid and docosatrienoic acid do not promote vaccenic acid accumulation in mixed ruminal cultures

Previous research found that docosahexaenoic acid (C22:6n-3) was a component of fish oil that promotes trans-C18:1 accumulation in ruminal cultures when incubated with linoleic acid. The objective of this study was to determine if eicosatrienoic acid (C20:3n-3) and docosatrienoic acid (C22:3n-3), n-3 fatty acids in fish oil, promote accumulation of trans-C18:1, vaccenic acid (VA) in particular, using cultures of mixed ruminal microorganisms. Treatments consisted of control, control plus 5 mg of C20:3n-3 (ETA), control plus 5 mg of C22:3n-3 (DTA), control plus 15 mg of linoleic acid (LA), control plus 5 mg of C20:3n-3 and 15 mg of linoleic acid (ETALA), and control plus 5 mg of C22:3n-3 and 15 mg of linoleic acid (DTALA). Treatments were incubated in triplicate in 125-mL flasks, and 5 mL of culture contents was taken at 0 and 24 h for fatty acid analysis by gas-liquid chromatography. After 24 h of incubation, the concentrations of trans-C18:1 (0.87, 0.88, and 0.99 mg/culture), and VA (0.52, 0.56, and 0.62 mg/culture) were similar for the control, ETA, and DTA cultures, respectively. The concentrations of trans-C18:1 (5.51, 5.41, and 5.36 mg/culture), and VA (4.78, 4.62, and 4.59 mg/culture) were also similar between LA, ETALA, and DTALA cultures, respectively. These data suggest that C20:3n-3 and C22:3n-3 are not the active components in fish oil that promote VA accumulation when incubated with linoleic acid.     

奶粉脂肪酸与乳制品风味关系研究

用气质（GC—MS）联用色谱分析了11个商业奶粉样品的脂肪酸组成以及含量,每个样品均检测到了28种脂肪酸,在表现奶粉风味的4个呈味脂肪酸,也即辛酸、己酸、壬酸和葵酸中只检测到了辛酸和葵酸。辛酸和葵酸含量在进口奶粉中普遍高于国产奶粉。国产奶粉中辛酸和葵酸的含量以2号最好,3号其次。亚油酸含量在国产奶粉中普遍高于进口奶粉。     

气相色谱法同时快速测定食品中丙酸、山梨酸、苯甲酸及脱氢乙酸

通过液液萃取净化样品研究,建立了食品中丙酸、山梨酸、苯甲酸、脱氢乙酸及其盐含量气相色谱同时快速测定方法,适用于固体非酯(脂)类食品的检测。结果表明:丙酸的回收率在85.1%~91.3%之间,其余3种防腐剂的回收率均在95.2%~99.4%之间;实验室内变异系数(CV,n=6)最大值≤4.7%,4种防腐剂检出限均在0.002 g/kg以下。4种目标物在有杂质干扰时,可用不同的极性毛细管柱做进一步的确认。本方法具有适用范围广、检测效率高、重现性好、准确度高、检出限低的特点,推广应用对我国食品安全的监督检验具有重要的意义。     

花生四烯酸、二十二碳六烯酸和二十碳五烯酸 在炎症中的作用概述

心脑血管疾病、肿瘤、糖尿病、神经系统疾病、自身免疫等疾病严重危害着人类的生命和健康,并消耗着大量医疗资源。事实上,很多疾病发生和发展的背后都伴随着炎症反应,炎症是众多疾病的病理基础,甚至是导致这些疾病的诱因。炎症本身是机体的防御性反应,但过度的炎症反应和长期慢性炎症会损害机体的稳态。炎症的调节和控制由炎症介质介导,花生四烯酸(arachidonic acid,AA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和二十碳五烯酸(eicosapentaenoic acid,EPA)等长链多不饱和脂肪酸(10ng-chain polyunsaturated fatty acids,LC-PUFAs)的衍生物是一类重要的调控炎症的介质。炎性细胞间的交流和细胞内信号传递与LC-PUFAs有关。AA经环氧酶和脂氧合酶合成的类二十烷酸主要起促炎作用,但有的也有抗炎作用。DHA和EPA在体内起抗炎作用,由它们合成的消退素(resolvins,Rvs)和保护素(protectin,PD)是重要的抗炎活性物质。DHA和EPA还可以干扰炎性细胞内信号传导途径来抑制炎症反应。本文从炎症与疾病的关系、LC-PUFAs的衍生物及其促炎和抗炎机制等方面综述了AA、DHA和EPA在炎症中的作用。     

酸味酿造产品中三酸比例评析

酸味酿造产品中乳酸、醋酸、丁酸共存,但比例不同形成的酸味特征也不同。控制不同的环境条件,创造出不同的微生物区系,形成不同的三酸比例,才能形成不同的产品风格。该文对常见的酸味酿造产品中微生物区系的变化及三酸含量进行了分析。     

Growth of Aeromonas hydrophila K144 as Affected by Organic Acids

The influence of different acids on the aerobic growth kinetics of Aeromonas hydrophila was studied in BHI broth with 0.5 and 2.0% NaCl incubated at 5 and 19°C. Growth curve data were analyzed by the Gompertz equation and a nonlinear regression program; generation and lag times were calculated from the Gompertz parameters. Type of acid, pH, NaCl level and temperature influenced lag and generation times. The organic acids (acetic, lactic, citric and tartaric) inhibited growth at higher pH values than inorganic acids (HCl and H₂SO₄). The high NaCl level interacted with type of acid and pH to restrict growth of the organism at the lower temperature of incubation. Acetic and lactic acids were effective in controlling the growth of A. hydrophila and could readily be combined with low holding temperature to render foods free of the organism.     

杂多酸催化合成辛酸蔗糖酯

以蔗糖、辛酸为原料,杂多酸为催化剂合成辛酸蔗糖酯。用L16(45)正交设计优化实验,高效液相色谱法分析反应液组成。考察了催化剂种类和用量、反应温度、原料配比、反应时间等因素对辛酸蔗糖酯产率的影响,发现以二甲基亚砜为溶剂、蔗糖与辛酸摩尔比1∶9、磷钨酸用量为蔗糖质量的2.0%、110℃反应时间6h,蔗糖转化率达60%,产物产要是二酯。动力学研究发现,蔗糖反应级数为一级,反应表观速率常数为0.0059min-1(90℃)、0.0117min-1(110℃),反应表观活化能Ea=39.57kJ/mol。     

气相色谱法同时测定保健食品中的5种 不饱和脂肪酸

目的建立气相色谱法同时测定保健食品中亚油酸、α-亚麻酸、二十碳五烯酸(eicosapentaenoic acid,EPA)、二十二碳六烯酸(docosahexaenoic acid,DHA)和二十二碳五烯酸(docosapentaenoic acid,DPA)的含量。方法样品先采用氢氧化钾甲醇溶液进行皂化处理,再用三氟化硼甲醇溶液甲酯化,经HP-FFAP色谱柱(30m×0.53 mm,1.0μm)分离测定。结果 EPA甲酯、DHA甲酯、DPA甲酯、亚油酸甲酯、α-亚麻酸甲酯分别在0.03927~1.178、0.04200~1.260、0.03449~1.035、0.08368~1.255、0.08482~4.241 mg/mL的浓度范围内线性关系良好,相关系数r均大于0.999;检出限分别为0.0039、0.0042、0.0034、0.0042、0.0042 mg/mL;加标回收率在91.1%~109.3%之间,相对标准偏差均小于5%。结论该方法操作简单快捷,适用于保健食品中亚油酸、α-亚麻酸、EPA、DPA和DHA的测定。