凉果中二氧化硫的快速高效检测方法探究

本文利用凯氏定氮仪对凉果及其制品进行蒸馏处理,并利用电位滴定仪中的电位突跃替代淀粉指示剂对滴定终点进行判定,建立了自动电位滴定仪滴定二氧化硫含量的快速高效检测方法。     

凯氏定氮法测定半固态复合调味料蛋白质含量

借助自动凯氏定氮仪,建立一种测定半固态复合调味料中蛋白质含量的方法,考察取样、消化、蒸馏等关键步骤对结果的影响。结果表明,利用凯氏定氮法测定(NH₄)₂SO₄标准品中氮的回收率高于97%,测定3种典型半固态复合调味料蛋白质含量相对标准偏差均小于0.5%。此方法具有误差小、准确度高、能耗低等优点,是半固态复合调味料蛋白质检测的优选方法。     

KDN型定氮仪测定粮食中粗蛋白质含量的相关问题探讨

目前测定蛋白质的方法和仪器很多,为了提高蛋白质含量检测结果的准确性和检测效率,依据GB/T 5511-2008《谷物和豆类氮含量测定和粗蛋白质含量计算凯氏法》要求,常用定氮仪来测定粮食中粗蛋白质含量。对此方法中化学试剂硫酸的选择及实际操作进行了探讨。     

粗脂肪自动测定仪与残余法快速测定菜籽含油量

比较索氏抽提法、残余法、粗脂肪自动测定仪法、近红外法与粗脂肪自动测定仪残余法5种测定方法,检测油菜籽含油量的准确性与效率。研究不同条件下,粗脂肪自动测定仪残余法测定油菜籽含油的最佳条件,以达到简化操作、节省时间提高效率的目的。对2014年全国208份油菜籽样品测定,粗脂肪自动测定仪残余法检测油菜籽含油量结果与标准方法测定结果一致。粗脂肪测定仪残余法仪器条件为:加热功率90%、每个抽提管放入5个样品包、抽提时间5 h、淋洗时间0.5 h、溶剂回收15 min。完成一批样品处理,能达到单个样品提取时间11.5 min与国标法相比,为索氏抽提法时间的18.2%,残余法的54.5%,能极大地提高工作效率,自动化程度高,具有较大的适用性。     

干百合中二氧化硫含量测定的不确定度分析

本文依据国家标准GB 5009.34—2022中充氮-蒸馏酸碱滴定法对市场上采购的干百合样品中的二氧化硫含量进行测定,通过建立数学模型,对不确定度来源进行分析、评定和合成,以保障测定结果的可信度,提高实验室检验检测能力。结果表明,干百合样品中二氧化硫含量为(0.690±0.014)g·kg^-1,k=2,不确定度的主要来源为样品重复测量引入,其次是实际消耗氢氧化钠标准滴定液的体积。     

酱腌菜中二氧化硫残留量的检测方法探讨

本文基于标准GB 5009.34—2022《食品安全国家标准食品中二氧化硫的测定》,根据标准适用范围,分别采用该标准第一法（酸碱滴定法）和第三法（离子色谱法）对酱腌菜中二氧化硫含量进行测定。结果发现,采用酸碱滴定法测定的结果高于离子色谱法测定的结果。通过研究酱腌菜产品的配料及开展单因子变量实验,发现酱腌菜产品中较高冰乙酸等添加剂会影响酸碱滴定法测定的二氧化硫的结果,而对采用离子色谱测定二氧化硫的结果没有影响。对离子色谱法测定酱腌菜中的二氧化硫进行方法验证实验,加标回收率在90.0%～93.2%范围内,相对标准偏差RSD为0.60%～1.3%,因此,标准GB 5009.34—2022第三法（离子色谱法）更适合酱腌菜产品中二氧化硫含量的检测。     

全自动定氮仪-液相色谱测定食品中丙酸

目的：建立操作简单、准确稳定、快速高效测定食品中丙酸的方法。方法：利用全自动定氮仪快速蒸馏的特点,对样品前处理过程中蒸馏试样初始体积、磷酸加入体积、馏出液是否补加磷酸等可能影响测定结果的因素进行逐一验证核实,优化高效液相色谱的样品前处理方法,并用于实际样品的测试。结果：面包和豆腐的方法检出限可以达到0.1 g·kg^-1,当加标浓度为2 g·kg^-1时,面包的加标回收率为76.08%～83.98%,相对极差约为4.9%;豆腐的加标回收率为76.75%～83.24%,相对极差约为4.1%。结论：该方法操作简单快速、结果准确稳定,可以用于面包和豆腐等食品中丙酸的测定。     

进口大豆不同水分检测方法应用研究与分析

本文根据化验室仪器配置实际情况,选取谷物快速水分测定仪、定温定时烘干法、近红外检测仪和卤素快速水分测定仪检测进口大豆水分含量,以国家标准105℃烘箱法为标准比对4种不同仪器方法检测结果,选出适合粮库不同检测需要的检测方法。依据大量比对试验的数据结果选择出准确度最高的快检方法为卤素快速水分测定仪法,设计3因素2水平正交试验,比较3因素对水分结果的影响大小及各因素下准确性高的最优水平,对试验结果进行方差分析,从精密度和准确性两方面确定使用卤素快速水分测定仪检测进口大豆的最佳条件为设定温度120℃、称样量6 g和粉碎粒度20目,从而指导企业生产应用。     

全自动蒸馏-甘油浴法测定配制酒中的氰化物

将全自动蒸馏与甘油加热方式相结合,建立了一种快速测定配制酒中氰化物含量的方法。研究蒸馏过程中的功率、加水量、吸收液的浓度、蒸馏时间、去除高沸点有机物的加热方式和温度对配制酒中氰化物测定的影响,并与国家标准方法 GB 5009.36—2016第一法进行比对,对百香果配制酒、鹿鞭酒、人参酒3种样品中的氰化物含量进行检测分析。结果表明,全自动蒸馏-甘油浴法的回收率为82.4%～85.7%,标准偏差为2.6%～3.2%,国标方法回收率为70.9%～81.8%,标准偏差为10.8%～13.9%。与国家标准方法相比,该方法所使用的时间较短,步骤简单,结果测定准确可靠,可实现配制酒的高通量准确检测。     

200袖珍式谷物水分测定仪

美国马里兰州Ｔｒｅｂｅｒ工业公司研制出一种袖珍谷物水分快速测定仪 ,其精确度为±０．５% ,达合于测定大豆、玉米和其它谷物。因在测定过程中采用了绝缘措施 ,故能保证其测值的精确性。所测含水量范围为 :大豆１０%～３０ % ,玉米为１０%～２４%。测出的数字在数字显示器上即可读出。这种谷物水分测定仪操作简单 ,只要将测试样装入仪器上部的样品室 ,并按一下按钮即可。该仪器由４节“ＡＡ”型电池供电 ,仅需定期更换电池 ,不需要任何其它的维护和保养。译自 :美国《ＦｏｏｄＥｎｇｉｎｅｅｒｉｎｇ》200袖珍式谷物水分测定仪…     

碱水解-分光光度法测定食品中的色氨酸含量

本研究通过碱水解-分光光度法,建立了小米、面粉、鸡蛋、大豆、牛肉、蘑菇（干）、鱿鱼、紫菜、葵花籽和全脂乳粉中色氨酸含量的测定方法。结果表明,回收率在93.6%～97.0%,RSD <5.0%,该方法准确度好,灵敏度高,满足GB/T 27404—2008中对方法回收率和精密度的要求,并且为了验证方法的可行性,本试验通过购买了各类产品进行验证,将该方法应用于实际各类食品中色氨酸含量的检测,且结果表明不同产品的样品之间,色氨酸的总量差异较大。该方法为市面上可接触到的食品的安全性监察提供了技术支持和指导。     

2018—2020年榆阳区食品中铝元素残留量调查

目的:了解榆阳区食品中铝含量超标的状况,为加强食品化学污染物的监督和控制管理提供科学依据。方法:分析汇总2018—2020年榆林市榆阳区食品安全监督抽检结果,对铝残留量不合格项目等信息进行分析。按GB 5009.182—2017的方法检测,按GB 2762—2017、GB 2760—2014和《国家卫生计生委关于批准β-半乳糖苷酶为食品添加剂新品种等的公告》(2015年第1号)进行评价。结果:从3年总体抽检情况来看,铝残留量不合格问题主要集中在淀粉及淀粉制品(粉丝、粉条类、凉粉)、油炸面制品、其他粮食加工品(包子、馒头类)以及糕点。从不合格项目来看,主要是含铝食品添加剂的“两超”(超范围、超限量)。结论:榆阳区粉类制中的铝残留量较高,主要与传统工艺中使用含铝食品添加剂有关,当地监管部门需重视,加强高风险食品靶向性抽检。     

The effects of food sales taxes on household food spending: An application of a censored cluster model

This study proposes a model of household food spending that accounts for zero censoring and can be applied to data collected through a clustered survey design to investigate the impact of food sales taxes on three groups: households who are eligible for and participate in the Supplemental Nutrition Assistance Program (SNAP), households who are eligible but do not participate in the program, and households who are not eligible for the program. We find that SNAP participating households are largely insensitive to grocery taxes and respond to restaurant taxes by shifting more of their food dollars towards at-home foods. Among households who are eligible for SNAP but do not participate in the program, grocery taxes reduce spending on foods purchased for at-home consumption, and thereby increase the amount of the total food budget allocated to away from home foods. This is concerning from a nutrition and health standpoint since away from home foods tend to be more calorie dense and nutritionally poorer than at home foods.     

Consumption Trends of Edible Mushrooms in Developing Countries

Abstract

Mushrooms are an important commodity worldwide. However, a thorough understanding of consumption trends is not yet available. In developing countries, the importance of edible mushrooms within consumer preferences and perceptions has not been studied. We carried out a study (2000-2003) to understand the patterns of mushroom consumption in central Mexico, where most wild/cultivated mushrooms are produced and/or marketed. About one-half (49.4%) of urban consumers bought mushrooms, independently of their social level [fresh or canned: white button mushroom (Agaricus), oyster mushroom (Pleurotus), shiitake (Lentinula). Preferences and perceptions from Mexican consumers depended on the social level. Mushroom prices were considered very or moderately expensive. Mushrooms were markedly more expensive than foods widely consumed. The variation of mushroom prices was a major factor influencing consumption. Basic data to carry out further marketing research are discussed, as well as an integral strategy considering social levels and regions to increase mushroom consumption.     

Dietary Globalization in Chinese Breakfasts

Demand for nontraditional foods is on the rise in China. Data from household surveys and consumer food diaries in Beijing, Nanjing, and Chengdu are examined to measure the effects of demographics on consumption of nontraditional food products. We focus on bakery and dairy products, two categories of foods that are rarely consumed in traditional Chinese breakfasts. We find that income, time constraints, and education positively affect the inclusion of nontraditional foods in the breakfast meal. Our results suggest that younger consumers are leading the transition to new global consumption patterns that integrate nontraditional foods into urban Chinese breakfasts. The implications of these findings for wheat and milk production and processing industries are discussed.     

动物源性食品中抗生素残留的快速检测方法研究

畜牧业养殖中存在滥用抗生素的情况,导致动物源性食品内的抗生素残留严重超标,对人体健康产生威胁.分析抗生素残留种类,科学采用前处理技术,开发出关于动物源性食品抗生素残留检测的有效方法,有助于保障食品质量安全.本文对抗生素残留的危害进行详细分析,介绍了动物源性食品中抗生素残留的种类及检测方法,为相关研究提供参考.     

Food Consumption Trends in the Pacific Rim

The growing affluence of the Pacific Rim countries has changed food consumption patterns. Diets in the region have become more diverse and well-balanced nutritionally. Western-style foods are becoming increasingly popular and available to people in the region. The rapid growth of fast-food chains and supermarkets present U.S. agricultural exporters with a myriad of opportunities for exporting food products to the Pacific Rim. Food producers who are willing to modify their products to the tastes of Pacific Rim consumers will have the most success. By reformulating food products and developing new packaging technologies more high-value foods can be sold in the Pacific Rim. U.S. food processors must also develop improved methods of processing traditional foods eaten by people in the region into more convenient forms. Finally, it is important for U.S. agricultural exporters to keep a close watch on the changing trends in food consumption in the region in order to stay competitive and increase their opportunities for entering new markets.     

Food Consumption Patterns and Nutrition in Urban Java Households: The Discriminatory Power of some Socioeconomic Variables

Food consumption patterns are undergoing substantial change in many countries as economic development proceeds. The trend is a move away from traditional cereals towards higher-value and higher-protein foods. Explaining such changes only in terms of traditional economic variables can lead to biased estimates of income effects and perhaps biased projections of food demand. Household survey data from Indonesia are used to measure the importance of several socioeconomic variables in explaining differences in household food consumption patterns and nutrition. Household expenditure and the level of women's education are shown to be the most influential in this explanation.     

超高效液相色谱-串联质谱法在食品安全检测中的应用

目的:探究超高效相色谱-串联质谱法在动物源性食品检测中的应用。方法:样品采用乙酸乙酯提取、氮气吹干,经ACQUITYUPLC BEH C18柱超高效液相色谱分离后电喷雾串联质谱法检测,采用负离子方式多反应模式监测,内标法定量。结果:目标化合物在1.0~100 ng·m L^-1呈现良好的线性关系,相关系数r≥0.9929;氯霉素类药物检出值为0.3μg·kg^-1,低于标准方法检测低限、检测限;精密度测定,相对标准偏差为0.4%~2.3%,说明方法精密度良好。结论:超高效相色谱-串联质谱法简单、快捷、灵敏度高,满足食品及保健食品市场监管及检验需求。