酿酒酵母菌胞内海藻糖提取工艺参数的优化

建立了超声破碎酿酒酵母细胞和冷三氯乙酸化学浸提海藻糖的工艺，探索了离子色谱分析技术条件，采用响应曲面法（RSM），研究了液料比R、超声功率W、工作时间T1、超声总时间T2和浸提时间T3等5个试验关键因子对海藻糖提取的影响规律，并构建了动态控制的数学模型，得到了海藻糖提取最优工艺参数依次为：尺为7、W为698W、T1为4．9s、T2为7．3min、T3为9min。结果表明：模型极显著，具有可行性和有效性，超声功率、工作时间和超声总时间对海藻糖提取量的影响最大，为生产中的应用提供了科学依据。     

免疫亲和柱净化高效液相色谱荧光法测定调味品中赭曲霉毒素A

建立了免疫亲和柱净化高效液相色谱法测定调味品中赭曲霉毒素A。样品用甲醇与NaHCO3体积比为60:40的溶液提取,经免疫亲和色谱柱纯化,应用液相色谱法检测。结果表明,空白样品按照质量分数为1.0,20,50μg/kg添加赭曲霉毒素A,回收率为75.0%～102.0%,精密度小于15%,方法检测灵敏度为0.5μg/kg。免疫亲和柱净化高效液相色谱法测定调料中赭曲霉毒素A是一种简单、快速、准确的方法。     

干柱层析法制备油茶总皂苷对照品初探

目的 研究干柱层析法制备油茶皂苷对照品的方法。方法 原料用60 %乙醇超声提取,浓缩至无醇味,石油醚脱酯后用正丁醇按3:1体积比加入萃取。取正丁醇层并真空浓缩至干,干法上样于100目~200目硅胶柱色谱分离,用乙酸乙酯-甲醇-正丁醇-水(2:1:4:7)的上相展层;根据Rf值取出相应的条带并用甲醇淋洗收集蒸干,薄层及理化性质检测。结果 该方法所制样品由薄层色谱为一点,纯度较高。结论 该方法简便、实用且制备量大,可作为油茶总皂苷对照品。     

Antioxidant properties of blackberry and blueberry fruits grown in the Black Sea Region of Turkey

Seven wild and ten cultivated blackberries (Arapaho, Bartin, Black Satin, Bursa 1, Bursa 2, Cherokee, Chester, Jumbo, Navaho, and Ness), and six lowbush (Vaccinium arctostaphylos) and four highbush (Vaccinium corymbosum) blueberries fruits (Ivanhoe, Jersey, Northland, and Rekord) were analyzed for total anthocyanins, total phenolics, and antioxidant activity as ferric reducing antioxidant power (FRAP) in this study. The respective ranges of total anthocyanin and total phenolic contents of the tested samples were: blackberries, 0.95–1.97 and 1.73–3.79 mg g⁻¹ and blueberries, 0.18–2.94 and 0.77–5.42 mg g⁻¹. FRAP values varied from 35.05 to 70.41 μmol g⁻¹ for blackberries, 7.41 to 57.92 μmol g⁻¹ for blueberries. Wild blackberries had the highest FRAP values while wild blueberries had the highest total phenolic and total anthocyanin contents. A linear relationship was observed between FRAP values and total phenolics for blueberries (r = 0.981). The anthocyanin pigments in samples were isolated and characterized by high-performance liquid chromatography (HPLC) with UV–visible detection. Cyn-3-glu was the predominant anthocyanin in all blackberry fruits.     

气相色谱-嗅觉测量法鉴定蒌蒿中的香气化合物

 采用顶空固相微萃取法提取了蒌蒿样品中的挥发性成分, 利用气相色谱-嗅觉测量法(GC-O)并结合气相色谱质谱联用分析(GC - MS) , 鉴定了萎蒿中的香气化合物。共检出21个呈香化合物, 基于其嗅感强度, 反式- 2 - 己烯醛、水芹烯、顺式- 罗勒烯、3 - 崖柏酮、樟脑, 黄瓜醛、( - ) - 龙脑和( - ) - 乙酸龙脑酯被认定为形成蒌蒿香气的重要化合物。     

DME发动机非常规排放物的检测与分析

用气相色谱仪和傅立叶红外光谱仪对燃用DME的ZS195柴油机的排气中的甲醛(HCHO)、甲酸甲酯(CHCOOCH3)、甲酸(HCOOH)非常规排放物进行了检测和分析。结果表明,DME发动机的尾气排放中,均检测到HCHO,HCOOCH3,HCOOH排放物,且甲醛是非常规排放物中的主要成分,甲醛、甲酸甲酯的排放量随转速上升而略有上升,随负荷增加而不同程度的减少,而甲酸排放量变化则不甚明显。     

Preliminary study of patients with chronic mountain sickness by GC-TOF-MS based serum metabolomics analysis

AIM: To evaluate specific metabolomics profiles in the serum of patients with chronic mountain sickness (CMS) and to explore the potential metabolic biomarkers in the native Tibetans living on the Qinghai-Tibet Pla-teau.METHODS: A gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) approach as a metabolomics technique was used to evaluate metabolic differences. The native Tibetan CMS patients (n=10) and healthy Tibetan controls (n=10) were enrolled from YuShu in Qinghai province in this study. The serum samples were collected and analyzed by GC-TOF-MS coupled with a series of multivariate statistical analyses such as principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA) and orthogonal partial least squares discriminant analysis (OPLS-DA).RESULTS: The intergroup differences between CMS patients and control subjects have been observed. A list of differential metabolites and several top altered metabolic pathways have been identified. The levels of fumaric acid, an intermediate in the tricarboxylic acid (TCA) cycle, and inosine were highly upregulated in the CMS patients, suggesting a greater effort to hypoxic adaptation in high elevation area. Other differential metabolites, such as methyl phosphate, 2-ketoadipate, lyxose and phytanic acid were also identified. Importantly, the differential metabolites possessed higher area under the ROC curve (AUC) values, indicating an excellent clinical ability for the prediction of CMS. Increased levels of amino acids (isoleucine, glycine, serine, L-cysteine, citrulline and trimethyllysine) were detected in CMS group, yet significantly decreased levels of sulfuric acid, oxamic acid, lyxose and glutamine were also detected in CMS group than those in control group. At the same time, the levels of ribose and glucose-1-phosphate were markedly elevated in CMS group (P<0.05).CONCLUSION: The metabolic activities are significantly altered in the serum of CMS patients. High altitude hypoxia may act on the disturbed glucose metabolism and amino acid metabolism in part of the Tibetan triggered by CMS.     

Disulphide structure of high-molecular-weight (HMW-) gliadins as affected by terminators

This study aimed at elucidating SS-bonds of HMW-gliadins (HGL) from wheat with the focus on terminators of glutenin polymerisation. HGL from wheat flour extracts non-treated or treated with the S-alkylation reagent N-ethylmaleinimide (NEMI) were compared. HGL from wheat flour Akteur were isolated, hydrolysed with thermolysin and the resulting peptides pre-separated by gel permeation chromatography and analysed by liquid chromatography/mass-spectrometry using alternating electron transfer dissociation/collision-induced dissociation. Altogether, 22 and 28 SS-peptides from samples without and with NEMI treatment, respectively, were identified. Twenty-six peptides included standard SS-bonds of α- and γ-gliadins, high-molecular-weight and low-molecular-weight glutenin subunits. Eleven SS-bonds were identified for the first time. Fifteen peptides unique to HGL contained cysteine residues from gliadins with an odd number of cysteines (ω5-, α- and γ-gliadins). Thus, gliadins with an odd number of cysteines, glutathione and cysteine had acted as terminators of glutenin polymerisation. Decisive differences between samples without and with NEMI treatment were not obvious showing that the termination of polymerisation was already completed in the flour. The two HGL samples, however, were different in the majority of ten peptides that included disulphide-linked low-molecular-weight (LMW) thiols such as glutathione and cysteine with the former being enriched in the non-treated HGL-sample.     

Polymerisation of gluten proteins in developing wheat grain as affected by desiccation

The breadmaking quality of wheat is affected by the composition of gluten proteins and the polymerisation of subunits that are synthesised and accumulated in developing wheat grain. The biological mechanisms and time course of these events during grain development are documented, but not widely confirmed. Therefore, the aim of this study was to monitor the accumulation of gluten protein subunits and the size distribution of protein aggregates during grain development. The effect of desiccation on the polymerisation of gluten proteins and the functional properties of gluten were also studied. The results showed that the size of glutenin polymers remained consistently low until yellow ripeness (YR), while it increased during grain desiccation after YR. Hence, this polymerisation process was presumed to be initiated by desiccation. A similar polymerisation event was also observed when premature grains were dried artificially. The composition of gluten proteins, the ratios of glutenin to gliadin and high molecular weight-glutenin subunits to low molecular weight-glutenin subunits, in premature grain after artificial desiccation showed close association with the size of glutenin polymers in artificially dried grain. Functional properties of gluten in these samples were also associated with polymer size after artificial desiccation.     

金属表面处理用混合硅烷体系中硅烷水解度的测定

硅烷工作液的水解度数据可为建槽过程中浓缩液稀释倍数以及硅烷工作液循环利用研究提供重要依据。以双-（3-三甲氧基硅基丙基）胺（BAS）和乙烯基三乙酰氧基硅烷（VTAS）的混合体系为研究对象,异丙醇为内标物,采用气相色谱内标法对BAS/VTAS体系中两种硅烷的水解产物CH₃OH和CH₃COOH的浓度进行精确定量,并通过计算得到两种硅烷的水解度数据。该方法的有效性采用红外光谱法、极化曲线和CuSO₄点蚀法进行验证。结果表明：气相色谱法能够有效、快速地表征BAS/VTAS混合体系中两种硅烷的水解度,其结果可作为硅烷水解液性能评判的定量依据。