基于HPLC-ELSD法测定食醋中5种还原糖的含量

目的:建立一种同时测定食醋中果糖、葡萄糖、蔗糖、麦芽糖和乳糖的高效液相色谱法。方法:食醋样品经处理后,采用HPLC-ELSD,以果糖、葡萄糖、蔗糖、麦芽糖和乳糖为对照品,固定相为Agilent ZORBAX NH2 (250 mm×4.6 mm,5μm),流动相为乙腈-水(70∶30)。结果:5种还原糖在色谱柱上得到有效的分离,在0.5～10.0 mg·mL~(-1)范围内呈良好的线性关系,平均加样回收率在97.19%～104.03%,相对标准偏差(RSD)为2.12%～3.27%。对两个不同企业赤水晒醋进行测定分析,结果显示不同企业以及不同年份的赤水晒醋中糖含量有较大的差异。结论:该方法结果准确,重现性好,适用于食醋中糖含量的测定。     

平顶山烟区烤烟化学成分与评吸质量的关系

2008年选取平顶山烤烟烟叶样品63个,进行化学成分分析和评吸质量鉴定.分析结果表明,烟叶中烟碱、总氮、氯、总挥发性酸、总挥发性碱含量适宜;总糖、还原糖、淀粉含量偏高,钾含量偏低,仅为 133%.烟碱、氯、淀粉、总挥发性碱变异系数较高,总氮、总糖、还原糖、钾、总挥发性酸变异系数较低,评吸质量较好,特别是劲头和燃烧陛表现较优.相关分析结果表明,烟碱、钾、氯、总挥发性酸与评吸质量相关性较显著.生产中应适当降低烟碱、氯、总挥发性酸含量,提高钾分量,以进-步改善烟叶质量.     

对国标gb/t15038-2006中总糖还原糖测定方法的改进

国标gb/t15038-2006葡萄酒、果酒通用分析方法中总糖、还原糖的检测方法有高效液相色谱法、直接滴定法和问接碘量法.通常实验室的常规检测方法采用直接滴定法,但该方法对样品中总糖含量、实验过程中的加热温度、滴定操作、滴定速度以及实验人员技术等教有严格要求.     

如何正确控糖

<正>当下年轻人正在将控糖以全新的形式内化为自己的生活方式。控糖控的到底是什么“糖”？为什么要控糖？如何控糖？糖的种类联合国粮农组织（FAO）和世界卫生组织（WHO）对于“糖”的定义是：对单糖、双糖和糖醇的统称。单糖包括葡萄糖、果糖和半乳糖等。葡萄糖是一种甜味糖，可以在人类的甜味受体上引起甜味感受，也是人体代谢中最主要的能量来源之一。果糖存在于水果、蜂蜜、甜菜等食物中，是人类日常饮食中的一种甜味物质。半乳糖可在奶类产品或甜菜中找到。     

食品中糖类物质国家标准检验方法的探讨

一、背景介绍糖类物质是多羟基醛和多羟基酮及其缩合物,或水解后能产生多羟基醛和/或多羟基酮的一类有机化合物。根据分子的聚合度,糖类物质一般分为单糖(如葡萄糖、果糖)、低聚糖(含2～10个单糖结构的缩合物,常见的是双糖,如蔗糖、乳糖和麦芽糖等)和多糖(含10个     

提高果糖生产水平的策略探析

作为一种全天然的新糖类,果糖具有口感好、甜度高、升糖指数低等优点。在当前市场果糖需求趋于多元化的情况下,果糖生产主体除了要根据果糖的市场需求和销量制定科学的生产决策以外,还要对果糖的生产进行持续性的研究和提升,以满足不断增加的果糖需求。文章在概括果糖生产工艺的基础上,对影响果糖生产水平的一系列因素进行了分析,并根据影响因素提出提高果糖生产水平的具体策略,以促进果糖生产水平的有效提高。     

国内外甲基异丁基酮生产与市场分析

2006年世界甲基异丁基酮生产能力约为392.5 kt,主要用于溶剂和橡胶助剂领域,2006年国内甲基异丁基酮生产能力为15 kt,需求量约为47.7 kt左右.本文介绍国内外甲基异丁基酮生产现状、市场需求,重点分析国内甲基异丁基酮供求现状,目前我国已成为甲基异丁基酮主要消费国.并对我国甲基异丁基酮工业发展提出一些建议.     

含氟聚芳酰胺的合成

用实验室合成的类双酚单体4-（4-羟基苯基）二氮杂萘-1-酮,在碳酸钾催化下与2-氯-5-硝基-三氟甲苯经亲核取代反应先合成一种二硝基化合物;再在钯催化下与水合肼发生还原反应制得一种具有扭曲,非共平面结构和大取代三氟甲基的新型二胺单体2-（4-氨基-2-三氟甲基苯基）-4-[4-（4-氨基-2-三氟甲基苯氧基）苯基]二氮杂萘-1-酮。由此含氟二胺单体和两种商品化二酸进行膦酰化缩聚反应制得了一系列主链具有扭曲,非共平面结构和大取代侧基的聚芳酰胺。     

蜂蜜中葡萄糖、果糖和蔗糖含量测定方法比较研究

比较化学方法和旋光计法测定蜂蜜中葡萄糖、果糖和蔗糖含量的优缺点。本文通过对蜂蜜中葡萄糖、果糖和蔗糖含量测定值进行比较和F检验法验证,结果表明,旋光法测定蜂蜜中葡萄糖、果糖和蔗糖含量的前处理方法简单,分离程度高,分析时间短,明显提高了检测效率,且其准确性和重复性好,是测定蜂蜜中糖含量的理想方法。     

测定葡萄酒中总糖第二方法探析

本文论述了葡萄酒中总糖含量的测定方法。通过3,5-二硝基水杨酸法、蒽酮比色法和间接碘量法进行测量,经多次实验数据分析得出,3,5-二硝基水杨酸法较适用于常规葡萄酒总糖含量的测定,数据结果较准确,操作起来较简便。     

果糖及其衍生物的应用研究进展

本文综述了果糖的基本性质及其在药物制剂、药物合成、化工中间体合成等方面的应用进展情况.     

我国果糖生产及市场发展趋势

介绍了果糖的代谢特性、技术发展历史和生产技术，以及国内现状和发展前景。     

The synergistic effects of maltodextrin and high‐fructose corn sweetener 90 in a fat‐reduced muffin

Low‐fat muffins were prepared using as fat substitutes a combination of maltodextrin and high‐fructose corn sweetener 90 (HFCS‐90), which replaced sucrose at a rate of 25%, 50%, 75% and 100%. The focus of the investigation was to determine the synergistic effects of these two ingredients on the physical properties in a low‐fat muffin. Results indicated that maltodextrin and HFCS‐90 were effective in maintaining moisture and water activity (a_w) levels similar (P > 0.05) to the full‐fat muffin. Texture profiles indicated that the low‐fat variations were firmer (P < 0.05) than the full‐fat counterpart. Increased levels of HFCS‐90 had a significant effect (P < 0.05) on crust and crumb darkening. Maltodextrin alone significantly (P < 0.05) impeded the staling rate during storage. However, when maltodextrin was combined with increased levels of HFCS‐90, the staling rate accelerated. The two ingredients were found to be effective in maintaining product quality, but HFCS‐90 could only be used up to a 50% replacement before any adverse effects in product quality were observed.     

不同系统粉黏度特性比较研究

小麦系统粉因为出粉部位不同导致不同系统粉的品质具有一定的差异。RVA粘度特性主要反映了小麦粉淀粉的糊化特性,还可以从一定程度上反映样品的α-淀粉酶活性,所以对面粉品质影响较大。通过实验表明：系统粉RVA糊化温度的顺序为2M〉总粉〉1B〉2B〉1M;峰值粘度、最低粘度、最终粘度和稀懈值的顺序1B〉2B〉1M〉总粉〉2M;回生值的顺序为：1B〉1M〉2B〉总粉〉2M。     

The Impact of Service Characteristics on the Switching Costs–Customer Loyalty Link

This research investigates the interrelationship between service characteristics and switching costs and makes two contributions to the service retailing literature: (1) As a means of better understanding the effectiveness of switching costs, the study suggests a two-dimensional typology of switching costs, including internal and external switching costs and (2) it reveals that the effect of these switching costs on customer loyalty is contingent upon four service characteristics (the IHIP characteristics of service). We carried out a meta-analytic review of the literature on the switching costs–customer loyalty link and created a hierarchical linear model using a sample of 1,694 customers from 51 service industries. Results reveal that external switching costs have a stronger average effect on customer loyalty than do internal switching costs. Moreover, we find that IHIP characteristics moderate the links between switching costs and customer loyalty. Thus, the link between external switching costs and customer loyalty is weaker in industries higher in the four service characteristics (as compared to industries lower in these characteristics), while the opposite moderating effect of service characteristics for the internal switching costs–loyalty link is noted.     

Critical innovation characteristics influencing the acceptability of a new pharmaceutical product format

This paper investigates the Critical innovation characteristics that influence the acceptability of a new pharmaceutical product format as perceived by medical service providers. Professional service providers act as "surrogate adopters" as they decide about the adoption of a product intended for their clients' use. We employ a qualitative research approach to explore which product related characteristics physicians evaluate when assessing the acceptability of a new product format in the pharmaceutical market. The main results concern (1) the distinct nature of a distributed adoption decision-making, (2) the refinement of relevant innovation attributes in a medical service context, and (3) the contextuality of innovation adoption. The research results show that innovation characteristics cannot be feasibly studied without taking into account the adoption context, here the medical service encounter and its institutional environment. Managerial implications of these findings are discussed.     

Comparative study of properties and acceptability of Haitian and US honey‐roasted peanuts

A honey‐roasted peanut product, flavoured with ginger and anise, was recently developed in Haiti in an effort to increase the consumption of locally grown peanuts. The objective of this study was to compare quality and consumer acceptability of the Haiti product with a traditional US‐manufactured brand. Haitian panellists (199) evaluated colour, appearance (dry/oily), crunchiness, peanut flavour and sweetness of the products using five‐point just‐about‐right scales. Colour (Minolta chromameter), hardness (TA.XT2i texture analyser fitted with a TA42 knife blade) and moisture (Denver IR‐30 moisture analyser), lipid (ethyl ether extraction) and sugar (Dionex DX‐500 high pressure liquid chromatography system) contents of the products were also determined. The Haiti product was significantly (P < 0.05) darker brown, harder and contained more (P < 0.05) sucrose and glucose but less (P < 0.05) lipid and fructose than the US product. Panellists indicated that crunchiness, peanut flavour and sweetness of both products were just right. The US product had acceptable appearance but was rated too light (hue angle = 69.6 ± 0.70, L‐value = 58.2 ± 0.47) in colour, whereas the Haiti product appeared too dry and dark (hue angle = 62.6 ± 2.79, L‐value = 44.6 ± 2.22). The Haiti peanuts were not deskinned, and their testae may have decreased the acceptability of the product's appearance and colour. The Haiti product was significantly (P < 0.05) just right to the female panellists and to the 21‐year plus panellists from all income groups. Deskinning of the peanuts and increased oil addition during roasting may improve the acceptability of the Haiti product, especially to 14–20 year olds. Decrease in sugar content may also make the Haiti product more appealing to this age group and to male Haitians.     

Cross-border mergers and acquisitions vs. greenfield foreign direct investment: The role of firm heterogeneity

We develop a general equilibrium model with heterogeneous firms to address two sets of questions: (1) what are the characteristics of firms that choose the various modes of foreign market access (exporting, greenfield FDI, and cross-border M&A), and (2) how does the international organization of production vary across industries and country-pairs? We show that the answers to these questions depend on the nature of firm heterogeneity. Depending on whether firms differ in their mobile or immobile capabilities, cross-border mergers involve the most or the least efficient active firms. The comparative statics on industry and country characteristics display a similar dichotomy.     

Successor characteristics,organisational slack,and change in the degree of firm internationalisation

In this paper, we use chief executive officer (CEO) succession events to explore the effects of successor characteristics, including outside succession and differences between a new CEO/existing chairman on changes in the degree of firm internationalisation. In addition, we examine the moderating effect of organisational slack on the relationship between successor characteristics and change in the degree of firm internationalisation. We test our hypotheses using a sample of 2000–2005 data from 160 successive observations of listed companies in Taiwan. The results show that a firm will opt for higher levels of change on an international scale when it is characterized by the following: (1) outside succession and (2) differences between the CEO successor and the existing chairman. Further, we find that organisational slack will positively moderate the relationship between successor characteristics and the change in the degree of firm internationalisation.     

A COMPARISON OF ACTUAL AND INTENDED CONSUMER BEHAVIOR IN RESPONSE TO RETAIL STOCKOUTS

Studies of consumer response to stockouts typically capture intended behavior. After a stockout experience, consumers are asked what they intend to do. In contrast, this research measured both intended and actual behavior. Consumers were interviewed twice; once immediately following the stockout experience to gauge intended behavior and a second time 30 days later to ask what they had actually done in response to the stockout. Accordingly, the goals of this research are to (1) compare consumer actual and intended behavior in response to stockouts and (2) examine product characteristics, consumer characteristics and situational variables that may explain the consumer's response. Key results suggest that indicated behavior is a good indicator of actual behavior in situations where the consumer intends to quit the search and a rather poor indicator when the consumer intends to delay the search. Finally, of the several product characteristics, consumer characteristics and situational variables examined, store loyalty, pre‐visit agenda and product uniqueness have shown most promise to help managers understand consumer actual and intended response to stockouts.