共查询到20条相似文献,搜索用时 93 毫秒
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采用毛细管气相色谱法测定了几种油脂的脂肪酸含量。对测定条件进行了选择,色谱柱为SE-30弹性石英毛细管柱(25m×0.22mm×0.2μm),柱温为190℃,载气流速为1mL/min,分流比为1∶100。对棉籽油、花生油、大豆油、小米乳芽油、猪油中所含脂肪酸进行了分析,结果表明,所测油脂中不饱和脂肪酸的含量普遍高于饱和脂肪酸,其中大豆油中亚油酸的质量分数(下同)最高,达60.02%;植物油中不饱和脂肪酸的含量高于猪油,其中小米乳芽油的最高,达84.33%,而猪油只有50.43%。 相似文献
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反式脂肪酸的含量过多会对人体健康带来巨大危害,成为了大家关注的焦点,根据调查发现,检测的食品中发现有百分之八十以上的食品,里面含有反式脂肪酸.反式脂肪酸含量不同,带给人们身体的影响也不同,制定食品中可以存在的含量标准也存在一定的缺陷.提高检测的技术,研究消解的方法都是目前急切需要解决的问题. 相似文献
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采用气相色谱-FID技术建立了一种测定化妆品中乌洛托品含量的方法。样品经过甲醇超声提取后,气相色谱分离,外标法定量测定。实验结果表明:乌洛托品质量浓度在2~200 mg/L范围内,线性方程为Y=0.715 8X-0.433 2,相关系数r=0.999 5,方法定量限为20μg/g,回收率为85.0%~106.8%,相对标准偏差小于5%(n=6)。该方法操作简单,重复性好,回收率高,是一种快速测定化妆品中乌洛托品含量的方法。 相似文献
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Malnutrition of micronutrients (vitamins and minerals) affects more than two billion people worldwide, especially in developing countries, largely due to low concentrations or poor bioavailability of these nutrients in the diet. In contrast, over-consumption, particularly of over-refined cereal-based foods, has contributed to the development of an “epidemic” of metabolic diseases in some developed countries. This review highlights recent progress in modifying crops and agronomic practice to increase health benefits. Mineral concentrations or bioavailability in crop edible parts can be increased by fertilisation, breeding or biotechnology. It is also possible to modify crops using transgenic technology to enable or increase the biosynthesis of vitamins and long chain omega-3 polyunsaturated fatty acids, or to modify the composition of starch or dietary fibre. Although technologically feasible now or in the near future, the development of micronutrient biofortified or composition-modified crops would also depend on other factors such as consumer acceptance, cost, regulations and national or international intervention. 相似文献
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《Food Policy》2014
There have been serious questions about whether lower-yielding farmers in developing countries, who are typically poor smallholders, benefit from genetically-modified crops like Bacillus thuringensis (Bt) corn. This article examines this issue by estimating the heterogeneous impacts of Bt corn adoption at different points of the yield distribution using farm-level survey data from the Philippines. A recently developed estimation technique called instrumental variable quantile regression (IVQR) is used to assess the heterogeneous yield effects of Bt corn adoption and at the same time address potential selection bias that usually plague impact assessment of agricultural technologies. We find that the positive yield impact of Bt corn in the Philippines tend to be more strongly felt by farmers at the lower end of the yield distribution. This result suggests that Bt corn could be a “pro-poor” technology since most of the lower-yielding farmers in the Philippines are poor smallholders with low incomes. 相似文献
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The study analyzes ex ante the adoption of insect-resistant Bt eggplant technology in India. Farmers’ willingness to pay (WTP) is estimated using the contingent valuation method. Given the economic importance of insect pests in eggplant cultivation, the average WTP for Bt hybrids is more than four times the current price of conventional hybrid seeds. Since the private innovating firm has also shared its technology with the public sector, proprietary hybrids will likely get competition through public open-pollinated Bt varieties after a small time lag. This will reduce farmers’ WTP for Bt hybrids by about 35%, thus decreasing the scope for corporate pricing policies. Nonetheless, ample private profit potential remains. Analysis of factors influencing farmers’ adoption decisions demonstrates that public Bt varieties will particularly improve technology access for resource-poor eggplant producers. The results suggest that public–private partnership can be beneficial for all parties involved. 相似文献
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在对原棉含杂率测试时,结果会因风耗的存在产生很大误差。通过实验,分析了原棉含杂实验过程中,产生测试误差的原因,并通过实验来证明了原棉回潮率直接影响风耗的关系,证明了杂质含量与风耗的大小没有直接相关,而易飘散细小颗粒的多少影响风耗,对原棉含杂测试数值产生影响。 相似文献
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分离苏云金芽孢杆菌(Bt)晶体蛋白常用的方法有液体双相法、密度梯度法、沉淀法、生物-物理分离法等,但这几种方法各有优缺点。从分离成本、仪器设备、纯度、产量、活性等方面考虑,在超声波处理、悬液制备和紫外线辐射3个方面进行了改进,提出了一种新的分离Bt晶体蛋白的方法,产品纯度可达90%以上,产率从原来的20%提高到28%。... 相似文献
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为加强对棉花质量的监督管理,推动棉花市场稳定发展,保护棉花交易各方的合法权益,国务院颁布并多次修订了《棉花质量监督管理条例》。棉花检验结果直接影响到棉花最终的交易价格,关乎各方经济利益。因此,对棉花检验数据的准确性提出了更高要求。基于此,文章通过阐述相关概念,剖析棉花杂质的类型及形成原因,并提出加强检验质量的保障措施,以期能够提高检验质量。 相似文献
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近几年,我国棉花价格一直处于波动状态,在市场的调节和政府的干预下,我国棉花产业的发展呈现出许多问题。通过对我国棉花生产的地域、棉花价格的变动、棉花品牌的建立、农户的行为等的多方面思考,总结了我国棉花发展面对的一系列问题,并提出解决问题的思路。 相似文献