野生猕猴桃酒苹果酸-乳酸发酵优良乳酸菌的筛选与耐受性研究

该研究通过形态观察及生理生化试验,采用酸性番茄（ATB）培养基从自然启动苹果酸-乳酸发酵（MLF）的野生猕猴桃酒中筛选MLF优良乳酸菌,并对其SO2、酒精、pH耐受性进行测定。结果表明,经初筛得到6株乳酸菌,分别编号为R6、R7、R11、R14、R15、R18。其中,菌株R6、R15可耐受SO2 80 mg/L,菌株R7可耐受SO2 100 mg/L;菌株R6、R7可耐受酒精度14%vol,菌株R15可耐受酒精度12%vol;菌株R6、R7可耐受pH 3.2,菌株R15可耐受pH 3.0。综合分析,菌株R6、R7和R15具有较强的SO2、酒精及pH耐受能力,为MLF优良乳酸菌。     

SO2及其他环境因子对苹果酸-乳酸细菌的影响

选择酒明串珠菌31DH和SD-1作为研究菌株,在ATB培养基中研究了SO2对苹果酸-乳酸细菌菌株的影响以及SO2与酒精和低pH之间的协同作用.结果表明,SO2的抑菌效果受pH值影响,pH值越低抑制作用越强烈;结合态SO2与酒精存在协同作用,但当浓度＞40mg/L时,结合态SO2浓度的增加对酒精抑制作用的增强并不明显.     

7株葡萄野生酵母菌的特性研究

对采集自新疆地区的7株(X1、X2、X3、X4、X5、X6、X7)野生型酿洒酵母的耐受性(包括高酒精浓度、SO2、低pH值、高糖浓度)和酿酒性能进行了分析,通过试验得出野生型本土酿酒酵母普遍能耐受12%酒精;在pH值为2.5时,菌株均生长;当SO2浓度达到250mg/L时,除X1外,所有野生酿酒酵母能够生长;能够耐受<50%葡萄糖浓度;经过发酵后,模拟酒中的总酸含量降低幅度较大(19.55%51.46%),均具有优良的耐受性和酿酒特性.     

青海东部野生酵母菌株抗性及发酵特性研究

以分离自青海的97株野生酵母菌株为材料,通过杜氏管发酵法初筛出35株发酵力强、有香味的酵母菌株,对其抗性和发酵特性进行研究.结果表明,35株酵母菌对SO2具有高度的抗性,大部分菌株在SO2浓度为600 mg/L时仍可正常生长并发酵;有7株耐NaCl高达120.0g/L,菌株QXN2在160.0 g/L的浓度下仍可正常生长并发酵;但大多数菌株的酒精耐受力弱,仅有6株可耐12%vol的乙醇,但已不能发酵产气;部分酵母菌株的耐温性较高,如菌株QHL4、QXS1、QJD12可耐受55℃高温;pH耐受范围在2.5～12.0之间,大部分菌株可在600 g/L的葡萄糖溶液中生长,其中9株仍可发酵产气.这9株发酵力较好且产香酵母的酒精发酵结果表明,4株产酒精度为0,具有浓郁的芳香;4株产酒度在2.1%vol～2.4%vol之间,且残糖较低,有浓郁果香.优良酵母菌株有望应用于面包生产、无醇饮料的开发、工业废水处理等领域.     

葡萄酒中植物乳杆菌的鉴定及其耐受性分析

本论文对4株分离自甘肃、宁夏产区葡萄酒中的乳杆菌进行鉴定并通过调整改良MRS培养基分析植物乳杆菌对酒精浓度、pH和SO2浓度的耐受性.结果表明:16S rDNA鉴定得到3株植物乳杆菌,在单一因素影响下,3株菌在pH 3.0条件下有良好生长,在16％vol酒精浓度可生长,110mg/L SO2浓度下可生长.在综合因素影响...     

酒精、SO2和pH值对酒类酒球菌生长特性影响

选用酒类酒球菌31DH和SD-1进行了试验,在ATB培养基中考察了环境因子低pH值、酒精和SO2对于菌株的影响以及这些限制因子之间的协同作用.结果显示低pH值是酒类酒球菌生长的主要抑制因子;低pH值与酒精之间存在协同作用,10%的酒精度是工艺控制的关键点.SO2的抑菌效果受pH值影响,pH值越低SO2的抑制作用越强烈;结合态SO2与酒精存在协同作用,但当结合态SO2浓度＞40(mg·L-1)时,其浓度的增加对酒精抑制作用的增强效果并不显著.     

酒类酒球菌的分离及发酵适应性研究

对我国葡萄酒主产区的酒类酒球菌进行了分离和筛选。通过考查分离菌株苹果酸—乳酸发酵性能后,对鉴定为酒类酒球菌的127株菌株进行了pH、SO2和酒精单因素耐受性试验,然后再选择抗性较好的初选菌株(8株)进行复合因子(pH×酒精×SO2)梯度筛选实验。结果表明,有4株酒类酒球菌分离株具有较强的苹果酸—乳酸发酵适应性,其中分离菌株O.oeniSD-2a对胁迫条件的适应性显著高于对照商业菌株O.oeni31DH。     

不同葡萄酒酵母耐受性试验比较

本文以新疆和青海葡萄产区的5株不同酿酒酵母(B-4、D-1、D-2、Q-42-2、Q-50-2)为试材,在分离纯化的基础上,对这5株酵母进行不同梯度酒精度、糖度、酸度和SO2的耐受能力测定.结果表明,菌株Q-42-2和Q-50-2的综合耐受能力较强,他们能在含糖量＞250g/L、SO2含量＞400mg/L、酒度＞15%、酸度pH＜2.0的发酵基质中发酵.证明Q-42-2和Q-50-2酵母菌株具有良好的耐受性.     

昌黎赤霞珠葡萄相关酿酒酵母的分离与筛选

以昌黎地区赤霞珠葡萄为样本,从中分离出5种酵母。通过菌落特征、菌体形态及赖氨酸培养基鉴定,初步确定其中4株为葡萄酒酿酒酵母。通过高浓度酒精(10%~18%)、高浓度SO2(100~400mg/L),高糖浓度(10%~60%)和高温(37、42℃)的耐受性实验,初步筛选出两株可耐受14%浓度酒精、300mg/L SO2、50%的葡萄糖浓度及42℃高温的菌株。与市售的两种酿酒酵母进行葡萄酒发酵实验,将所得酒样进行理化分析及感官品评,结果表明菌株a发酵力强,较市售酵母菌发酵后挥发酸含量低,残还原糖含量为0.40g/L,且葡萄酒感官评价最高。最终选出菌株a为赤霞珠葡萄酿酒酵母最佳菌株。     

高产酸本土非酿酒酵母菌株的筛选及发酵性能研究

以25株本土非酿酒酵母菌为研究对象,采用酵母浸出粉胨葡萄糖（YPD）10培养基及Triple M改良模拟汁初筛,并进行耐受性（乙醇、SO2、糖及pH）测定及葡萄汁发酵,筛选能够有效增加葡萄酒酸度的优良本土非酿酒酵母菌。结果表明,非酿酒酵母菌株LT1及HU4产酸性能较好,具有较好的乙醇、SO2、糖和pH耐受性,其中菌株LT1能耐受乙醇体积分数12%、糖400 g/L及pH 2.75,菌株HU4能耐受乙醇体积分数6%vol、糖250 g/L及pH 2.75。菌株LT1和HU4在葡萄汁中启酵时间较短,发酵旺盛期CO2质量损失速率均＞0.8 g/（L·h）,乳酸产量分别为0.93 g/L、1.14 g/L,乙酸产量分别为0.38 g/L、0.42 g/L,具备酿造增酸葡萄酒的潜力。     

Isolation,Composition, Structure,Properties, Modifications,and Uses of Yam Starch

Starch is the major carbohydrate in yam tubers and can amount up to 80% of the dry matter. The starch quality determines the quality of food and industrial products made from yam tubers. This review summarizes the present knowledge of the isolation, composition, structure, property, modifications, and uses of starches from diverse yam species. Compared with other tuber and root starches, there is a lack of systematic information on the yam starches. This hinders the further development of yams as sustainable crops as well as the value‐added processing of the starches. Therefore, suggestions on how to better understand and utilize these starches are provided.     

Mineral contents of some southern Italian wines. II. Determination of Li, Na, Mg, K, Ca, Co, As, Rb, Sr, Ag, Sb, Ba

Following our study of the mineral contents of some Southern Italian wines, this work reports on the detection of 12 elemental components. The elements were determined using ICP-AES, flame atomic emission or absorption spectroscopy. The values determined for Li, Na, Mg, K, Ca, Rb, Sr and Ba were within the usual ranges for wines (average values for these elements were: 0.010, 26.2; 94.4; 888; 94.0; 3.30, 0.82 and 0.11 mg/l respectively). All the wines contained low levels of As, the concentrations of which were always under 0.20 mg/l, the maximum level permitted by E.E.C. standards. The measuring of Co, Ag, and Sb led us to ascertain, in all the wines, concentrations lower than 0.01 mg/l for Co and Ag and below the instrumental detection level for Sb (0.06 mg/l). In a previous study wines from D.O.C. areas of Southern Italy were analysed by the technique of inductively coupled plasma atomic emission spectroscopy (ICP-AES), for 14 minerals. This paper deals with further investigation of the mineral composition of the same wines for different metal constituents, analysed by ICP-AES, flame atomic emission, or atomic-absorption spectroscopy (two techniques). The first technique was applied to the detection of Co, As, Sr, Ag, Sb, and Ba. The alkaline metals Li, Na, K, and Rb were determined by flame atomic emission, a technique which possesses better detection limits for these elements. For Mg and Ca the atomic absorption methods were applied.     

卷烟中锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量分析

采用微波消解-电感耦合等离子体质谱法测定了41个牌号烤烟型卷烟和雪茄烟样品烟丝中的锂、铬、镍、铜、砷、硒、钼、镉、铊和铅含量,并按照类型和价位对卷烟中这10种有害元素含量进行了统计分析。结果发现:①卷烟中锂和铜的含量较高,铊的含量很低,铬、镍、镉、铅、砷、硒和钼7种元素的平均含量为0.55～4.42μg/g;②雪茄烟中铬、镍、砷、钼、镉、铊和铅的含量一般高于烤烟型卷烟,而硒元素的含量则相反,但差别较小;烤烟型卷烟中锂和铜的含量与雪茄烟没有显著差异;③高档卷烟中的锂、镍、镉、铊和铬含量较低,而砷、铅的含量较高;不同价位卷烟的铜、硒和钼含量差异不显著。     

Survey of trace elements (Al,As, Cd,Cr, Co,Hg, Mn,Ni, Pb,Se, and Si) in retail samples of flavoured and bottled waters

Concentrations of eleven trace elements (Al, As, Cd, Cr, Co, Hg, Mn, Ni, Pb, Se, and Si) were measured in 39 (natural and flavoured) water samples. Determinations were performed using graphite furnace electrothermetry for almost all elements (Al, As, Cd, Cr, Co, Mn, Ni, Pb, and Si). For Se determination hydride generation was used, and cold vapour generation for Hg. These techniques were coupled to atomic absorption spectrophotometry. The trace element content of still or sparkling natural waters changed from brand to brand. Significant differences between natural still and natural sparkling waters (p < 0.001) were only apparent for Mn. The Mann–Whitney U-test was used to search for significant differences between flavoured and natural waters. The concentration of each element was compared with the presence of flavours, preservatives, acidifying agents, fruit juice and/or sweeteners, according to the labelled composition. It was shown that flavoured waters generally increase the trace element content. The addition of preservatives and acidifying regulators had a significant influence on Mn, Co, As and Si contents (p < 0.05). Fruit juice can also be correlated to the increase of Co and As. Sweeteners did not provide any significant difference in Mn, Co, Se and Si content.     

Varied Composition of Tocochromanols in Different Types of Bran: Rye,Wheat, Oat,Spelt, Buckwheat,Corn, and Rice

The profiles of tocopherol (T) and tocotrienol (T3) homologues in 37 samples of seven different types of bran (rye, wheat, oat, spelt, buckwheat, rice, and corn), available on the Polish market, were studied. Tocochromanols were identified and quantified by reverse phase-high-performance liquid chromatograph/fluorescence detector and reverse phase-ultra performance liquid chromatography-electrospray ionization/mass spectrometry. Only rice bran contained all eight tocochromanol types. Corn bran lacked β-T3; rye, wheat, oat, and spelt bran lacked γ-T3 and δ-T3; and buckwheat bran lacked β-T3, γ-T3, and δ-T3. In buckwheat and corn bran tocopherols predominated (98 and 78%, respectively); whereas rye, wheat, oat, spelt, and rice bran were rich in tocotrienols (78, 76, 66, 87, and 66%, respectively). The average total tocochromanol contents in the oat, corn, spelt, buckwheat, wheat, rye, and rice bran were 5.5, 16.2, 15.8, 14.7, 12.8, 10.7, and 9.1 mg/100 g of dry weight, respectively. Tocochromanol concentrations in samples of the same type bran from different sources varied considerably. Better labeling of bran products to reflect this variation would assist with control of vitamin E daily dietary requirements.     

Optimization of extraction conditions of total phenolics, antioxidant activities, and anthocyanin of oregano, thyme, terebinth, and pomegranate

The purpose of this study was to evaluate the total phenolic extracts and antioxidant activity and anthocyanins of varieties of the investigated plants. These plants include oregano, thyme, terebinth, and pomegranate. The optimum extraction conditions including temperature and solvent of the extraction process itself were investigated. Total phenolic and anthocyanin extracts were examined according to Folin-Ciocalteu assay and Rabino and Mancinelli method, respectively. The effect of different extracting solvents and temperatures on extracts of phenolic compounds and anthocyanins were studied. Plant samples were evaluated for their antioxidant chemical activity by 2, 2-diphenyl-1-picrylhydrazl assay, to determine their potential as a source of natural antioxidant. Results showed that all tested plants exhibited appreciable amounts of phenolic compounds. The methanolic extract (60 °C) of sour pomegranate peel contained the highest phenolic extract (4952.4 mg/100 g of dry weight). Terebinth green seed had the lowest phenolic extract (599.4 mg/100 g of dry weight). Anthocyanins ranged between 3.5 (terebinth red seed) and 0.2 mg/100 g of dry material (thyme). Significant effect of different extracting solvents and temperatures on total phenolics and anthocyanin extracts were found. The methanol and 60 °C of extraction conditions found to be the best for extracting phenolic compounds. The distilled water and 60 °C extraction conditions found to be the best for extracting anthocyanin.     

ICP-MS测定饼干中的铅、砷、铬、镉、铜、锌、铁和锰

探讨了应用电感耦合等离子体质谱仪测定饼干中铅、砷、铬、镉、铜、锌、铁和锰8种重金属元素的方法。运用微波消解系统对样品进行消解,以铋、锗、钪和铟作为内标物,用ICP-MS对消解液进行检测,并采用国标方法对其结果进行验证。利用加标回收率试验和国家标准物质小麦(GBW 10052)检测试验考察了方法的准确性和可靠性。结果表明,该方法所测元素在标准溶液浓度范围内呈线性关系,相关系数均大于0.999,方法检出限在0.002~0.500 mg/kg之间,相对标准偏差均小于6.55%,本法与国标方法测量结果的相对偏差在3.73%~8.40%之间,加标回收率在88.0%~106%之间,标准物质的测定值与标准参考值符合要求。     

The effect of storage of canned juices on content of the metals Fe, Cu, Zn, Pb, Sn, Al, Cd, Sb and Ni

The increase in concentration of iron, copper, zinc, lead, antimony, aluminium, cadmium, tin and nickel over a 2 year's time of juices of peach (prunus persica), pear (pyrus communis), apricot (prunus vulgaris) and apple (malus pumila) was determined. The results show a considerable increase in Fe, Cu, Pb, Zn and Sn with time, while the change in Al, Cd, Ni and Sb is negligible.     

接装纸中汞、砷、铅等8种元素的分析研究

本文利用电感耦合等离子体发射光谱仪(ICP-AES法)同时测定接装纸样品中铅、铜、镉、铬、锡、锑元素含量,汞、砷元素含量采用冷原子吸收光谱法和银盐法测定.结果表明接装纸样品中锡元素含量最高,铜次之,汞、砷、铅相比,砷元素含量较高,部分样品中砷、铅元素含量超出食品包装用纸的最高限量标准.采用ICP-AES法同时测定接装纸6种元素,操作简便,重复性好,回收率高.此外,本文还对接装纸荧光物质和脱色程度进行了测定分析,从随机抽检的47份国产、进口接装纸样品看,进口白色接装纸无荧光,国产白色接装纸有荧光,珠光色接装纸个别有荧光,纸边为白色的接装纸荧光程度不一.脱色试验表明,进口接装纸,国产印刷型接装纸、珠光纸不脱色,涂布型接装纸均有不同程度的脱色.     

Analysis of cheese for histamine, tyramine, tryptamine, histidine, tyrosine, and tryptophane

A method is described for determining the content of selected biologically active amines (histamine, tyramine, tryptamine) and amino acids (histidine, tyrosine, tryptophane) in cheeses by high performance liquid chromatography. The amines and amino acids were quantified by employing a counter ion-containing mobile phase and by comparing peak areas of high performance liquid chromatography charts for sample cheeses versus standard cheeses containing known amounts of added amines based on dual injections of samples and standards. Recovery of amines and amino acids varied from 87.5 to 111%. Histamine, which has been associated with food poisoning in concentrations of 185 mg/100 g in Swiss cheese and 180 to 500 mg/100 g in fish, was found in concentrations above 500 mg/100 g in Swiss cheese. The high performance liquid chromatography analytical method should be useful for screening to detect cheese samples containing toxic amounts of histamine and for research studies designed to determine the cause and effect relationships for histamine production in cheese.