光度滴定仪法测定稻米脂肪酸值的研究

论述了测定稻米脂肪酸值的光度滴定仪法和基于光度滴定仪法的脂肪酸值测定仪的原理和特点,分析了脂肪酸值测定仪的准确度、稳定性、测定范围等使用性能,指出了仪器对滴定终点反应敏锐、准确,检测结果稳定,方便快捷,易学易用等特点。     

对微量凯氏定氮法测定蛋白质含量的改进

以经典的微量凯氏定氮法为基础,对消化装置进行了一定的研究和改进,使消化时间大大缩短;并针对混合指示剂必须现用现配且滴定终点不易判断的不足,选用酸度计代替混合指示剂判断滴定的终点,使测定结果的准确度提高。实验表明,改良后的蛋白质含量测定方法不仅操作简便,而且污染减少,结果更加准确。     

影响食盐中碘含量检测结果准确性的主要因素

碘是食盐重要的监测指标,研究了影响食盐中碘含量检测结果准确性的主要因素及试验过程中注意的事项。结果表明,对于加碘食盐而言,为保证检验结果的准确性,检测过程中应注意:(1)将碘盐研磨粉碎后均匀取样;(2)有效氯含量应适度过量,含量为3%较为适宜;(3)滴定过程中试样溶液滴定至浅黄色后再加入淀粉指示剂;(4)滴定终点以样液蓝色消失为终点,切勿直接滴定到澄清透明。     

介绍一台新型全自动化布奇(BUCHI)定氮仪

布奇定氮仪(瑞士进口)具有快速、准确、简便等优点。该仪器由三部分组成:BUCHI—430消煮器,322(蒸馏—滴定器),343(自动控制器)。消煮器可快速升温,仅一小时可完成整个消化过程,消化中的烟雾可直接导出室外或排入水中。蒸馏和滴定偶合在一起     

生物纳米材料在粮油食品检测中的应用

由于食品安全事件的频繁曝光,人们对于食品安全与品质的关注程度与日俱增。传统的实验室检测方法,虽然具有灵敏度高、检测结果准确可靠等优点,但是同样存在着检测周期长,样品前处理过程复杂繁琐,检测通量较低,仪器设备维护成本高,需要专业人员操作等不足,已无法满足目前食品安全与品质的检测需求。基于生物纳米材料的粮油食品检测方法具有成本低廉、方便、易于操作、仪器易于自动化和小型化、灵敏度高、选择性好等特点,本文就生物纳米材料在粮油食品中重金属离子、硝酸盐、纳米病原微生物的研究和应用进行概述,进一步了解生物纳米材料在粮油检测中的进展和作用。     

全自动脂肪酸值测定仪的研制

针对粮食脂肪酸值检测的过程自动化、批量检测、信息化的需要,设计了全自动脂肪酸值测定仪,运用自动控制技术实现进样、移液、加液、滴定和清洗的连续作业自动化,达到脂肪酸值的快速批量检测。该仪器的开发将减少整个检测过程中检验人员的工作量和劳动强度,提高检测效率,并采用射频技术满足实验室管理信息化的需求,具有广阔的市场应用前景。     

粮油中真菌毒素检测技术及其应用

综述了真菌毒素检测技术的发展及其在粮油检测中的应用,比较了目前正快速发展的新兴检测技术,通过分析经典仪器分析方法和以免疫反应为基础的现代快速检测方法的优缺点,探讨了真菌毒素检测技术今后的发展思路,并为真菌毒素快速检测技术在粮油检测中的选择和应用提供了参考。     

JZSG-Ⅱ型脂肪酸值测定仪的研究开发

1 概述 我国《稻谷储存品质判定规则》中将脂肪酸值作为判定粮食品质状态的重要指标。针对实际工作中脂肪酸值测定存在的手工滴定终点颜色变化不明显,操作人员的个体差异影响测定结果的一致性等问题,在我所开发的谷物脂肪酸值测定仪的基础上,为提高仪器的稳定性和测定数据的准确性,     

用双波长薄层扫描仪测定粮油中的黄曲霉毒素B_1

前言本文中就 CS—910双波长薄层扫描仪测定粮油中的黄曲霉毒素 B_1进行了详细的描述。这种方法就我国目前通用的常规方法中目视测定部份改为用仪器检测,具有灵敏度高、方法准确的特点。仪器测定的标准偏差为0～±5.96,测定浓度为0.2—20ng 时,方法偏差为±10.7。玉米中黄曲霉毒素 B_1的回收率为83—88.6,花生油中为66—133,花生仁中为78.9—144。一、仪器和药品仪器:CS—910双波长扫描仪;氙灯光源μ—235双笔记录仪;G-RIA 数字处理机。试剂:本文中所用的试剂同于《粮油食品卫生检测方法》一书中所述,全部为分析纯。     

面筋吸水量品质指标检测探讨

实施粮油品质检测，对于掌握储备粮油的品质变化，适时推陈储新，减少粮油损失起到了重大作用。但在具体实践中，不同化验室之间对同一样品所检测结果有时基本一致，有时相差很大；即使同一样品，同一化验室，不同的操作人员检测的结果误差也很大，使品质检测结论出现许多认识上的分歧，不能提供准确的决策依据。     

粮食酸度回收率测定方法的首次探讨

首次探讨了粮食酸度回收率的测定方法,为评价粮食酸度测定结果的准确性提供了依据。采用2台JDDY型自动滴定分析仪分别测定面粉酸度的回收率,实验结果表明,回收率在97.4%~109.7%之间,测试值与理论添加值之间具有较好的相关性,线性相关系数分别为r=0.9986、r=0.9992,能够满足目前粮食酸度指标的品质检验要求。     

JDDY型粮油滴定分析仪在稻谷玉米脂肪酸值测定中的应用

采用基于机器视觉技术的JDDY型粮油滴定分析仪代替人工滴定进行稻谷、玉米脂肪酸值的测定.通过添加亚油酸标准溶液测定稻谷、玉米脂肪酸值的回收率,验证采用滴定仪测定稻谷、玉米脂肪酸值的准确性.实验结果表明,稻谷回收率在99.5％～107.3％之间,玉米回收率在96.1％～105.7％之间,滴定仪对稻谷、玉米的测试值与理论添加值之间具有较好的相关性,线性相关系数分别为r=0.9993,r=1.0000,具有较宽的测量范围,能够满足目前稻谷、玉米试样脂肪酸值指标的品质检验要求.     

如何提高奥氏气体分析仪检测粮堆中CO_2和O_2浓度的准确度

介绍了检测粮堆中CO_2和O_2气体浓度所用奥氏气体分析仪的构造、原理、操作,提出了提高奥氏气体分析仪检测准确度的方法建议。     

粮食脂肪酸值测定方法的研究进展

脂肪酸值是粮食储存品质的重要指标。本文简要介绍提取粮食游离脂肪酸的各种溶剂,对滴定法、比色法和色谱法等粮食脂肪酸值测定方法的优缺点及其研究进展也作了探讨。     

我国粮油储藏标准体系的发展状况与研究

通过调研发达国家粮油储藏技术标准体系状况,依照我国有关政策、法规和标准,研究了我国粮油储藏标准体系构建的原则和目标,运用系统科学的理论和方法,制定了我国粮油储藏标准体系的框架,编制了粮油储藏标准体系表。     

2种裸燕麦籽粒硬度测定方法比较

裸燕麦（Avena nuda L.）籽粒硬度与其在收获、清洗和加工过程中籽粒的破损程度密切相关,也对其加工品质和食用品质有重要影响。确定裸燕麦籽粒硬度检测方法是全面了解其籽粒硬度形成机制的基础。利用单粒谷物特性测定仪（single kernel characterization system,SKCS）和质构仪（texture analyzer,TA）检测10份在仓储含水量条件下裸燕麦籽粒的硬度。结果表明,SKCS法测得硬度值为负值,变幅为-47.69~-15.81,且数据准确性较差;经过对籽粒形变量、压缩位移和上样量的统计分析,TA法是随机选取100颗籽粒,在籽粒形变35%时获得压缩至籽粒0.30mm位移处的硬度值,变幅为13.87’33.59N,数据能准确代表该材料的硬度值。籽粒硬度值受籽粒物理结构的影响,SKCS法测得硬度值与籽粒长呈正相关,TA法测得硬度值与籽粒宽呈正相关,相关系数分别为0.64和0.65。在籽粒物理特性和硬度值准确度等因素的综合评价下,质构仪更适合用于检测裸燕麦籽粒硬度。     

二十一世纪来我国粮食储藏技术新进展

综述了十来年国内粮食储藏技术研究进展和推广应用情况,分析了当前粮食储藏技术发展中存在的问题,提出了解决问题的对策,并展望了储藏技术未来发展趋势,旨在为更好地促进我国粮食储藏技术的健康发展,既实现粮食绿色安全储藏又保持粮食新鲜度提供一定参考.     

玉米群体光分布特征及其对产量和品质的影响

通过测定不同种植密度玉米群体的光能分布,研究了群体光能分布特征对玉米产量和品质的影响,结果显示,只有光照条件适宜的群体,才能充分利用光能,并可获得高产优质的玉米子粒。     

Can Mediterranean durum wheat landraces contribute to improved grain quality attributes in modern cultivars?

The variability for quality attributes existing in a collection of 154 durum landraces from 20 Mediterranean countries and 18 modern cultivars was determined with the ultimate goal of identifying potential quality-enhancing genotypes for use in breeding programs. Field experiments were conducted during 3 years under rainfed conditions in northeastern Spain. Environmental effects were the most important in determining protein content, grain yield and yellow color index of the endosperm (grain flour), and the least important in determining EU quality index (QI), gluten strength and grain filling rate. QI is a weighed composite index determined from protein content, gluten strength, yellow color index and thousand kernel weight. Multivariate analysis detected four groups; three including landraces and one comprising modern cultivars. Landraces from the eastern Mediterranean countries had the highest mean QI and the widest variability for individual quality traits, but were characterized by relatively small grains. Landraces from the western Mediterranean countries had greater grain filling rates and heavier grains. Protein content, gluten strength and yellow color index were similar between eastern and western groups. The low QI and reduced variability characterizing the landrace group from the north Balkan Peninsula support the hypothesis of a different origin for this group. Modern cultivars, as a group, were the most productive and showed high QI, but they had the lowest grain protein content and phenotypic variability. Landraces that could be used as sources of quality-improving attributes and/or those that could be used in breeding programs without substantial quality handicaps were identified from different groups. Landraces can be particularly useful in breeding programs to improve gluten strength, grain weight and accelerate grain filling rate.     

Dynamics of oil and tocopherol accumulation in sunflower grains and its impact on final oil quality

Tocopherols are one of the most important bioactive compounds in vegetable oils. It is known that these antioxidants present a dilution like relationship with oil weight per grain but the mechanism underlying this relationship are unknown. The aim of this work was to analyze the dynamics of tocopherol accumulation in sunflower grains, its relationship with oil accumulation and its effects on final oil quality in genotypes with different fatty acid composition. Three field experiments were conducted with genotypes with different potential fatty acid composition (a traditional, a high oleic and a high stearic−high oleic) and treatments with different source (intercepted solar radiation) or sink (grains) during grain filling to obtain varied grain filling conditions and grains with different oil concentration and oil unsaturation. Intercepted solar radiation modified oil per grain but did not affect tocopherol per grain. The rate of accumulation explained 79% and 74% of the oil and tocopherol per grain variation, respectively. When intercepted solar radiation increased, the duration of the period of oil and tocopherols accumulation increased, being the first the most responsive. These differences in the duration of accumulation periods are reflected in a larger relative increase in oil than tocopherols per grain and thus a dilution of the latter in the oil. These differences in the dynamics of oil and tocopherol accumulation are common to genotypes with different level of unsaturation. These results help to understand the mechanism associated with the dilution curve of oil tocopherol concentration reported in the literature.